rvin bse g S O ys th t r e a m E
THE EARTH OBSERVER May/June 2003, Vol. 15, No. 3
In this issue ... EDITOR’S CORNER
Meeting/Workshop Summaries Michael King Minutes of the March 2003 Aura Science EOS Senior Project Scientist Team Meeting ...... 3 CERES Science Team Meeting ...... 9 CloudSat/CALIPSO Science Team I’m proud to announce that the International Academy of the Digital Arts Meeting Summary ...... 14 and Sciences has selected two NASA Web sites for top honors in their ASTER Users Workshop ...... 17 respective categories. The NASA Home Page (at www.nasa.gov), managed SEEDS Update ...... 23 by Brian Dunbar and his team at NASA Headquarters in Washington, D.C., Other Items of Interest won the Webby in the “Government & Law” category. And NASA’s Earth Observatory (at earthobservatory.nasa.gov), managed by David Herring and CCSDS Lossless Data Compression to be Available in HDF-4 and 5 ...... 19 his team at Goddard Space Flight Center in Greenbelt, MD, won the Webby Aqua Mission Sponsors 2003 Engineer- in the “Education” category. ing Competition ...... 21 Additionally, both sites won “People’s Voice Awards” for their respective Kudos ...... 24 Earth’s Hidden Waters Tracked by categories. In keeping with the spirit of the Web’s capacity for global GRACE ...... 25 interactivity, the People’s Voice Award is determined by a popular vote in NASA’s ESE Sponsors Creative Problem which anyone in the world can vote for their favorites in each of the Solving competition ...... 30 Webby’s thirty categories.
Regular Features The Webby is the most coveted award by the on-line community (visit Earth Science Education Program www.webbyawards.com for details). Congratulations to the development Update ...... 31 teams for these two outstanding internet resources, and be sure to check EOS Scientists in the News ...... 32 them regularly for new informative and stimulating content. Science Calendars ...... 33 On a somewhat less celebratory note, the Landsat 7 mission is experiencing The Earth Observer Information/ Inquiries ...... Back Cover a problem with the Enhanced Thematic Mapper + (ETM+) multi-spectral scanning instrument. On May 31 the scan line corrector for the instrument encountered an anomaly, and operations have been halted pending a resolution. The scan line corrector adjusts the line-of-sight of the ETM+, tracing contiguous scan lines orthogonal to the satellite’s path. Without the scan line corrector, the ETM+ scan mirror traces a zig-zag pattern across the field-of-view resulting in gaps between scan lines.
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An anomaly tiger team, comprised of instrument, with greater spatial and Maryland, the MODIS Rapid Response engineers from NASA, USGS, and the spectral resolution than MSS. ETM+ Team, members of U.S. Forest Service ETM+ manufacturer, Santa Barbara was launched on Landsat 7, and is and NASA will participate in this Remote Sensing, is investigating the capable of even greater resolution. As a “Meet the Press” event. The animation cause before taking any action to restart result, the Landsat series of satellites on wildfires produced by the Scientific the scan line corrector. has produced an extremely valuable Visualization Studio at Goddard Space continuous data record of the Earth’s Flight Center will be featured at this The Landsat series of satellites has been land surface and coastal regions for event. This is just one of several Earth a keystone in land remote sensing since over 30 years. science applications programs devel- the original Earth Resources Technol- oped within the Enterprise, and ogy Satellite (ERTS-1) was launched in There will be a special Earth Showcase demonstrates the real socio-economic July of 1972. The second generation of press conference in July that will focus benefits of NASA’s Earth science Landsat satellites began with the on wildfire monitoring by NASA Earth program. launch of Landsat 4 in 1982, which observing satellites. EOS investigator carried the new Thematic Mapper (TM) Chris Justice at the University of
This image of Mt. Everest (center, circled) was acquired by Landsat 7’s Enhanced Thematic Mapper plus (ETM+) sensor on January 5, 2002. On May 29, 1953, Edmund Hillary, from New Zealand, and Tenzing Norgay, from Nepal, became the first humans to successfully climb to the peak of Mt. Everest, the tallest mountain in the world. Data for this image was provided by the Landsat 7 Team at NASA’s Goddard Space Flight Center.
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Minutes of the March 2003 Aura Science Team Meeting
— Anne Douglass, [email protected], Deputy Aura Project Scientist, NASA Goddard Space Flight Center
An Aura Science Team meeting was HIRDLS calibration was completed in (GOME) instrument to test the process- held March 18 – 21, 2003 in Greenbelt, December 2002. The signal-to-noise in ing system. The OMI team recognizes
MD. Four of the working groups the instrument exceeds requirements, that the NO2 retrieval relies on the a (validation, data systems, aerosols, and and it may be possible to include an priori information, and plans to develop education and outreach) met on March additional vertical scan (7 instead of 6) retrieval methods using constituent 18, and the full science team convened in the across-track direction within 4° assimilation. March 19-21. The Aura Project of latitude along track. With such low Mike Gunson, deputy to Reinhard Manager, Rick Pickering, provided an noise it is possible to complete the Beer (TES Principal Investigator), gave overview of the status of Aura, scans more rapidly. a time history for performance and stressing that Aura integration contin- Joe Waters (MLS Principal Investiga- modifications of TES during recent ues to benefit from experience with tor) reported that MLS noise is also tests that revealed problems with the Aqua. The project remains focused on lower than specifications. The preci- beam-splitter alignment. TES was in a launch date in January 2004. As of sion estimates provided so far are calibration at the time of the science the March meeting, three of the four based on maximum allowable noise, team meeting. TES signal-to-noise instruments, the Ozone Monitoring thus performance on orbit may be needs improvement, and options such Instrument (OMI), High Resolution better than presently advertised. as bandpass filtering are being investi- Dynamics Limb Sounder (HIRDLS), Changes to the MLS instrument, gated. and the Microwave Limb Sounder including replacement of a whisker (MLS)) had been delivered. Modifica- diode tripler with a planar diode Reports from Working Groups tions to the schedule will accommodate tripler, will be coordinated with late April delivery of the Tropospheric The Data System Working Group activities involving TES to minimize Emission Spectrometer (TES). Carolyn (DSWG), chaired by Scott Lewicki impact on the spacecraft schedule. Dent summarized results and plans for ,addressed issues that are common to spacecraft interface testing. The first Bert van den Oord represented all of the Aura Instrument Teams tests have included a collection of Pieternel Levelt (OMI Principal including data product formats, science simulated data. Future tests will Investigator). Synthetic OMI data are system interfaces and testing, quality simulate normal daily activities being produced using data from the assessment, tools, and end-user (including ground system contacts and Global Ozone Monitoring Experiment interests. At the last meeting, the team Tracking and Data Relay Satellite [TDRS] contacts) and contingency operations in case of emergency. Glen Iona provided a brief summary of the Mission Planning Review that was held in February for the Earth Science Data and Information System (ESDIS) project.
John Gille and John Barnett, HIRDLS co-Principal Investigators, reported that an improved retrieval procedure will take into account the line-of-sight Figure 1: The Aura Satellite temperature gradient along the limb.
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expanded on the current HDF-EOS concerning aerosols that are common Validation Aura File Format Guidelines to specify among the Aura instruments. The MLS The science team has paid great data types and field names and laid the cloud-ice retrieval will generate ice attention to the development of the groundwork for comparison of Level 2 water content values greater than 0.005 validation plan for Aura. The chal- 3 Aura products, including the use of a gm/m at 100 hPa (report by Dong Wu lenge from the Snowmass (1999) Dataset Validator tool. They also heard presented by Steven Massie). If meeting to the Aura Science Team is reports from the Earth Science Data HIRDLS performs as expected it will that validation data beyond routine and Information System (ESDIS) on retrieve ice water content on the order observations be obtained within the 3 science-system interfaces, secure data of 0.0001 gm/m . This leaves a data context of science missions. transfer, and ground-system tests gap for cirrus sizes that will not be Mark Schoeberl presented an over- (Mission Operations Science System measured by HIRDLS or MLS. Omar view of Aura validation and its [MOSS]). Additional topics included Torres gave an overview of the Total implementation plan including the the development of an EOSDIS Core Ozone Mapping Spectrometer (TOMS) development of ACDC and a trailer System (ECS) Metadata editor and the data record and aerosol detection facility. This overview illustrated the use of IDL and other tools for examin- capabilities, including detection of contributions of data from ground- ing products in HDF-EOS5. desert dust over bright reflective desert based networks, other satellites, and regions. These same capabilities are The Education and Public Outreach special observations. These special expected for OMI. Data from the Working Group (Ernest Hilsenrath, observations include data from balloon TOMS and OMI instruments should be chair) reported on recent activities with instruments and from aircraft missions. combined to produce a continuous its partners in getting the word out record of tropospheric aerosol over the Lucien Froidevaux presented a about Aura to peers, students and the past 25 years. Alyn Lambert presented summary of the March 18 Validation general public. The American Chemi- an overview of the development of the Working Group meeting. This meeting cal Society’s ChemMatters magazine, HIRDLS aerosol retrieval. The retrieval emphasized the routine datasets that which goes to 30,000 high school has been applied to sulfate aerosol will be used in Aura validation, teachers, has started on its 3rd dedi- loading for conditions in which the including meteorological datasets, cated issue on Aura and atmospheric aerosol amount is minimal (current sonde data, ground-based data, data chemistry. This issue will be released conditions). Finally, Steve Massie is from airborne instruments that are in conjunction with “Chemistry Week.” contacting those in the volcanology flown on commercial aircraft, and data The Smithsonian National Museum of community to find out how the Aura from other satellites. Plans were Natural History is working with NGST teams can be contacted within hours of presented (B. Bojkov) for a central to display a half-scale model of the a major volcanic eruption. location for correlative data as part of Aura spacecraft as part of the Atmo- the ACDC. The correlative datasets, spheric Chemistry exhibit to open in B. Bojkov and E. Hilsenrath presented liaisons who assure that the data is Summer 2004. a proposal for an Aura Correlative Data available, and any issues associated Center (ACDC) to the Aura Validation A Global Learning and Observations to with the datasets are summarized in Working Group on Tuesday and to the Benefit the Environment (GLOBE) tables that can be found at eos- entire Aura Science Team on Wednes- workshop was held to familiarize aura.gsfc.nasa.gov/index.html. Several day. The data center’s planned func- teachers with Earth science and how airborne missions have been identified tions and implementation were measurements tropospheric ozone and between 2004 and 2006 that are discussed. Agreement was reached on aerosols, made by students as part of expected to play an important role in the role of the ACDC, the correlative GLOBE, could provide results for the validation of Aura data. These data format (HDF-4 and HDF-EOS5) science and validation. Visit include INTEX/E (midlatitudes, that will be implemented, and the set of earthobservatory.nasa.gov for recent summer 2004), Tropical Composition tools that will be made available to the 3 articles on atmospheric chemistry. and Climate Coupling (TC )/Cirrus validation teams. A formal proposal for Regional Study of Tropical Anvils and The Aerosol Working Group (Steven the ACDC has been submitted to HQ Cirrus Layers (CRYSTAL — tropics, Massie, chair) considers issues for funding. NH winter 2004/5, NH summer 2005),
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INTEX/W (midlatitudes, spring 2006), develops the conceptual framework for profiles (MLS, TES), and cirrus clouds and the Polar Auroral Plasma Physics improved collaboration between the (MLS, HIRDLS) — along with observa- Spacecraft (POLAR — high northern airborne missions with each other and tions from other A-Train participants — latitudes, winter 2006). The instrument with spaceborne platforms including will form a much more comprehensive teams are asked to clarify their needs Aura. Jim talked about the missing picture of clouds, aerosols, and water for aircraft mission data. This two-part components of the document and the vapor than is possible using observa- action item requires the teams to progress being made. The importance tions from any single platform. There specify the types of measurements that of developing this conceptual frame- are many challenges to using this data would be most useful (e.g., MLS and work was underscored during discus- in concert. For example, the nadir HIRDLS both desire along-track sions of the proposed Tropical Compo- footprints from the various instruments profiles for 800 – 1000 km), and also to sition, Cloud, and Climate Coupling vary drastically. To foster creative identify any needs for aircraft data that Experiment (TC4) (see below for thinking and to raise awareness of the are not met by these missions. summaries of presentations given by complementary observations expected Paul Wennburg and Ross Salawitch). from other platforms, one session of the Daniel Jacob reported briefly on a field There are multiple questions concern- Aura science team meeting featured experience during TRACE-P to provide ing processes in the tropics and presentations about the A-Train and the CO profiles for validation of observa- subtropics that will be addressed by the instruments that comprise it. Chip tions by Measurements Of Pollution In two phases of this mission. The flights Trepte presented an overview of The Troposphere (MOPITT) on Terra. that are proposed will provide unique CALIPSO, which will provide observa- Validation was not a priority for any and useful information; however, tions of the vertical distribution and flight, but fortunately 50% of the common sense and analyses show that extinction for clouds and aerosols, planned flights provided an opportu- the information that can be obtained by emissivity of clouds, and single- nity for coincidence with Terra over- aircraft is limited. The satellite data scattering albedo for aerosols. Charles passes, and flight plans were designed have the potential to provide both Miller described the measurements of to obtain correlative profiles on two- context for interpretation of aircraft CO expected from OCO. Mark thirds of these flights. For measure- 2 observations and some quantitative Schoeberl presented an overview of ments made in clear sky, agreement information to understand the pro- the A-Train and reviewed some of the between the in situ profiles and cesses on the global scale (see summary measurement capabilities of its remotely sensed profiles is excellent. of presentation by Dessler). This on- component missions. These include Profiles were obtained in the presence going dialogue promotes the coordi- infrared cloud properties, temperature, of cirrus, but the MOPITT team has not nated application of data from satellite and water from instruments on Aqua; yet produced retrievals for this and aircraft to complex science vertical distribution of clouds by condition. These in situ profiles will questions. CloudSat; and measurements of aerosol provide essential information once the and cloud polarization from a French retrieval issues have been dealt with The A-Train Centre National d’Etudes Spatiales satisfactorily. One problem with the The scope of scientific applications for (CNES) mission called Polariazation flight-of-opportunity approach to data from Aura and several other and Anisotropy of Reflectances for validation is that no effort was made to satellites will be broadened by launch- Atomspheric Science copuled with obtain profiles for a range of atmo- ing Aura and three Earth System observations from a lidar (PARASOL), spheric conditions. Luck did not Science Pathfinder (ESSP) missions — which will also be part of the forma- provide a range, and the actual CloudSay, Cloud-Aerosol Lidar and tion. It will also be possible to combine measurements vary by only about 10%. Infrared Pathfinder Satellite Observa- data from multiple missions to produce This experience underscores the need tions (CALIPSO), and the Orbiting such quantities as observation-based for the Aura investigators to specify the Carbon Observatory (OCO) — to fly in assessments of the radiative effects of types of measurements that are formation with Aqua, in orbit since aerosol and clouds that will greatly required for successful validation. May 4, 2002. Aura observations of improve our ability to predict future Jim Anderson led a discussion on the cloud heights (OMI), aerosols (OMI, climate change.
Union of Missions, a document that HIRDLS), H2O and temperature
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Science Presentations emphasizing dedicated ground-based Joan Alexander showed examples of measurements. This project will momentum flux estimates using Presentations on topics of interest to provide a set of exclusive ground-based measurements made by the Cryogenic the Aura community were solicited for measurements, such as the NO lidar Infrared Spectrometers and Telescopes this science team meeting and are 2 data for polluted areas in the Nether- for the Atmosphere (CRISTA). The summarized below. lands, Multi-Axis Differential Optical temperature amplitude, vertical Laura Pan presented an overview of Absorption Spectroscopy-Method wavelength, and horizontal wave- the National Center for Atmospheric (MAXDOAS) measurements of NO2 in length must be determined simulta- Research (NCAR) Upper Troposphere Paramaribo, and aerosol data. This data neously to determine momentum flux
Lower Stratosphere Initiative. This set will be used both to validate NO2 and this has been a daunting analysis initiative will bring together a critical and aerosol products and to improve task for satellite observations. These mass of collaborators in a focused the retrieval algorithms. It will also results are relevant to HIRDLS observ- program of observations and analysis. provide insight into the relationships ing strategies, particularly if the
Measurements that are part of this between aerosol properties and NO2 in instrument performs as expected and it initiative during 2005 may be useful for polluted regions. is possible to include an additional validation of Aura data; and, once scan. validated, Aura data will play a role in Dorian Abbot presented seven years (1995-2001) of HCHO column data for A presentation was given by Ross this initiative. 3 North America from the Global Ozone Salawitch on the combination of TC Paul Wennberg spoke of two closely Monitoring Experiment (GOME), and and CRYSTAL-TWP complemented the related campaigns, the Tropical showed that the general seasonal and talk given by Paul Wennburg, and Composition and Climate Coupling interannual variability of these data is emphasized the synergistic science that 3 4 (TC ) Experiment and the Tropical consistent with that produced using the would result from the creation of TC . Western Pacific component of CRYS- GEOS-CHEM 3D tropospheric chemis- The importance of measurements of 3 TAL (CRYSTAL-TWP). Both TC and try and transport model, and isoprene isotopes of water vapor (to study the CRYSTAL-TWP emphasize the from current emission models. Re- processes which dehydrate air entering processes that maintain observed gional discrepancies with the seasonal the stratosphere) and measurements of humidity levels in the upper tropo- patterns predicted from these simula- very short-lived organic species and sphere and lower stratosphere. This tions may reflect flaws in the emission their products (to determine the budget talk revealed a strategy for a mission models. of chlorine- and bromine-containing TC4 that combines the objective of TC3 species entering the stratosphere) was and CRYSTAL-TWP and also meets Collette Heald presented results from stressed. Aura validation requirements. the GEOS-CHEM 3-D tropospheric Pepijn Veefkind showed trends in the chemistry and transport model along Ken Jucks provided an overview of the aerosol optical thickness calculated with satellite observations of carbon Far-Infrared Spectroscopy of the from the global dataset derived from monoxide (CO) from MOPITT and Troposphere (FIRST) instrument that is TOMS observations for 1979 to 2001. aircraft measurements from the being developed to fly on a balloon During this time period the emissions TRACE-P aircraft mission. MOPITT payload. FIRST spectra can be inverted of aerosol precursors SO2 and NO2 have observed four episodes of trans-Pacific to yield profiles of upper tropospheric been drastically reduced. Because most transport of Asian pollution during and lower stratospheric temperature of the aerosols over Europe are spring 2001 that are simulated by the and water vapor. Once validated, composed of sulfates and nitrates, it is GEOS-CHEM model. The February 26- FIRST measurements can contribute to expected that the reduction in emission 27 episode was sampled as a succession the validation measurements from will be manifest by a decrease in of pollution layers at 15-40º N by the HIRDLS and MLS on Aura and also aerosol optical thickness and accompa- TRACE-P aircraft over the northeast AIRS, CERES, and MODIS measure- nied by regional warming. Pacific. The layers originate from the ments on Aqua and Terra. February 22 event of Asian outflow to Steve Massie discussed development Mark Kroon presented the OMI the Pacific along a warm conveyor belt of a cirrus cloud field that can be used in future tests of the HIRDLS retrieval validation plan for aerosols and NO2, ahead of a cold front.
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algorithm. The cloud field is based carbon monoxide, and water vapor. profiles from SBUV. Assimilation of upon 1994 observations from LITE These analyses indicate that mixing of additional data, improved forecast (Lidar-in-Space Technology Experi- stratospheric and tropospheric air error covariance models, and incorpo- ment, a forerunner of CALIPSO), and masses forms a transition layer in the ration of chemistry models each lead to extinction was normalized to values vicinity of the thermal tropopause. incremental improvements in the measured by the Halogen Occultation The results also indicate that a Pres- assimilated ozone fields. Experiment (HALOE) on the Upper sure-Volume (PV) based tropopause Atmosphere Research Satellite (UARS). definition does not work well in Krzysztof Wargan demonstrated the These studies clarify the expected locating the transition layer. impact of changing the forecast error performance for HIRDLS constituent covariance model from a version Mark Olsen used Lagrangian trajecto- retrievals in the presence of cirrus assuming static correlations to a flow- ries to show that a significant fraction layers. following scheme that captures the of the air in the tropical upper tropo- Lagrangian short-term horizontal Hiroo Hayashi used observations from sphere/lower stratosphere during the evolution of those correlations. The the Southern Hemispheric ADditional wet/warm phase of the tape recorder ozone fields produced from the OZonesondes (SHADOZ) network to originates from the extratropical Asian assimilation system using the flow- investigate tropical tropospheric ozone monsoon. Air reaches tropopause following covariance compares better from the NASA GSFC ozone assimila- levels through convection within the with independent observations within tion system. The shape of the annual monsoon and is transported the regions where data were not mean vertical profile from assimilated equatorward. Data from Aura and assimilated, particularly at high ozone, produced using wind fields Aqua instruments should clarify the latitudes in both hemispheres. from a prototype version of the relative contributions of air that have Goddard Earth Observing System Data passed through the cold tropical David Lary used an assimilation Assimilation System (GEOS–4), tropopause and moist monsoon air to scheme including a photochemical compares better with observations than the observed tape recorder signal. model constrained by multiple that produced using winds from a coincident observations to reconstruct Pepijn Veefkind presented different previous operational system (GEOS-2). full diurnal cycles from limited aspects of a new algorithm to improve observations and to check their Andrew Dessler showed satellite and the total ozone product from the chemical self-consistency. This ap- in situ evidence that the effects of GOME instrument by combining the proach propagates sunrise and sunset convection on the Upper Troposphere / GOME experience with the new insight information obtained through solar Lower Stratosphere (UT/LS) were gained from development of OMI occultation for validation of measure- dependent on the relative humidity of algorithms. The proposed algorithm ments made at other times of day. the UT/LS where the convection includes an accurate method to derive occurred. If convection injects mass and use the cloud fraction and height, a Gloria Manney showed process-based into a region of high humidity, the tool that recalibrates the GOME Level 1 diagnostics for meteorological fields convection can dehydrate that region, data and the main features of the OMI from a number of data assimilation while convection into regions of low Differential Optical Absorption systems, including versions 3 and 4 of humidity hydrates that region. He also Spectroscopy (DOAS) total ozone the Goddard Earth Observing System emphasized the importance of satellite algorithm. Data Assimilation System (GEOS DAS), data for the problem; the pervasive Ivanka Stajner showed how the ozone the European Centre for Medium- undersampling of aircraft data make data assimilation system at NASA’s Range Weather Forecasting (ECMWF), those data virtually impossible to Data Assimilation Office (DAO) is the MetO (formerly known as UKMO), interpret on their own. preparing for Aura with a series of NCEP, and the NCEP reanalysis. Laura Pan explored the utility of experiments investigating the use of Modeling studies, particularly those conceptual definitions of the extratropi- column ozone from either the Total involving transport or temperature- cal tropopause as a material surface or Ozone Mapping Spectrometer (TOMS) dependent threshold phenomena, can as a mixing layer using fine scale in situ or the Solar Backscatter UltraViolet be highly sensitive to the choice of measurements of temperature, ozone, (SBUV) instrument, and vertical ozone meteorological analysis used.
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A few posters were displayed through- optical depth and single-scattering processes. Results were found to differ out the meeting. Nathan Winslow albedo derived from near-UV observa- depending on the source of meteoro- presented a poster detailing improve- tions by the Earth Probe Total Ozone logical fields used in the analysis. He ments in the NASA GSFC ozone Mapping Spectrometer with observa- also found that there was a net adia- assimilation product relative to ozone tions made at AERONET stations in batic flux of mass into the middle sondes when MLS profiles are assimi- Africa and in the United States. TOMS world. lated along with TOMS columns and and AERONET single-scattering albedo The next Aura Science Team meeting SBUV profiles. A poster by Alexander agree within 0.03. Mark Schoeberl will be held in Pasadena, CA, the week Sinyuk presented a method for used diabatic heating rates to calculate of September 30, 2003. This meeting retrieval of the imaginary part of the the flux of mass from the stratosphere will include a field trip to visit the Aura refractive index of desert dust aerosol to the troposphere, and attributed the spacecraft before its January 2004 at near-UV wavelengths. Omar Torres mass change in the lowermost strato- launch. showed comparisons of the aerosol sphere to diabatic and adiabatic
A silver swath of sunglint surrounds half of the Hawaiian islands in this true-color Terra MODIS image acquired on May 27, 2003. Sunglint reveals turbulence in the surface waters of the Pacific Ocean. If the surface of the water were as smooth as a mirror, we would see the circle of the Sun as a perfect reflection. But because the surface of the water is ruffled with waves, each wave acts like a mirror and the Sun’s reflection gets softened into a broader silver swath, called the sunglint region. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC.
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CERES Science Team Meeting
— Gary G. Gibson, [email protected], NASA Langley Research Center — Shashi K. Gupta, [email protected], NASA Langley Research Center
The 28th Clouds and the Earth’s Radiation Budget (GERB) success, Niño event are large, up to 80 W/m-2. Radiant Energy System (CERES) launch dates, and mission lifetimes. A comparison of ERBE-like and Science Team meeting was held in CERES on NPP reduces the gap risk to SRBAVG results for March 2000 Norfolk, VA, on May 6-8, 2003. The 6%. showed a large clear-sky bias away meeting focused on the new Monthly CERES Instruments on Terra and from the Tropics, small LW differences Top-of-Atmosphere/Surface Averages Aqua in most zones, and a large latitudinal (SRBAVG) products, early results from Kory Priestley (LaRC) gave the dependence in all-sky SW and net flux Terra Angular Distribution Model instrument calibration/validation biases. (ADM) development, cloud accuracy report. The Terra Deep Space Calibra- TRMM and Terra Time-Averaged results from Terra, Terra Edition2 tion sequence executed flawlessly and Products instrument and ERBE-like (ERBE is the science data analysis is continuing. Earth Radiation Budget Experiment) David Young (LaRC) reported that the Initial results indicate minimal changes results with calibration refinement, Terra gridded geostationary (GGEO) from pre-launch measurements of scan Aqua Instrument and ERBE-like products are now being run for the first angle dependent offsets. Terra Edition2 product status, and performance of year of data. Improvements related to bi-directional scan (BDS) and ERBE-like Terra surface fluxes. The next CERES surface emissivity, sun angle, and time- products are available through Decem- Science Team Meeting is planned for dependent calibrations were incorpo- ber 2002. A factor of five improvement September 23-25, 2003 in, Hampton, rated. Other enhancements involving has been achieved in stability and bias VA. geostationary satellite navigation, for shortwave (SW) and daytime surface albedo, and bringing in new CERES on NPOESS and NPP longwave (LW) Edition2 products. satellites are in progress. Validation is Terra has unprecedented stability levels Bruce Wielicki (Langley Research continuing for the archived Tropical of ~0.1%/yr for the CERES climate Center [LaRC]) noted that a clear Rainfall Measuring Mission (TRMM) record. Aqua Edition1 BDS products picture of CERES on the National Polar SRBAVG product. A beta version of the are now available. Intercalibrations Orbiting Environmental Satellite Terra SRBAVG marks the first of a new between Terra and Aqua allow the System (NPOESS) is not expected to generation of global monthly mean instruments to be placed on the same emerge until next year. The Earth products. The Terra beta Monthly radiometric scale: The SW and LW/ Science Enterprise has directed that Gridded TOA/Surface Fluxes and night agreement is within 0.4%; LW/ provisions be made to accommodate a Clouds (SFC) product is in the archive, day agreement is better than 0.7%; and CERES instrument on the NPOESS and the Aqua beta SFC product has window channel (WN) agreement is Preparatory Project (NPP) spacecraft to been delivered. within 1.0%. fill the anticipated gap in the radiation TRMM/Terra Clouds and Radiative Terra Edition2 ERBE-Like Flux budget data record between Aqua and Swath (CRS) Results NPOESS. This leaves the door open to Takmeng Wong (LaRC) examined the fly CERES on NPP, but a final decision time series of CERES/Terra Edition2 Tom Charlock (LaRC) reported that has not been made. Aqua and Terra tropical-mean and global-mean top-of- TRMM CRS Edition2C was produced, will not be de-orbited; the latest atmosphere (TOA) radiation budgets but still neglects organic carbon estimate of risk of a gap in broadband and found no statistically significant aerosols and has a few other known radiation budget data without CERES trends during the first 34 months of errors. The LaRC Fu-Liou radiative on NPP is 16 to 42% through 2012, data. His analyses also revealed that transfer code is being modified to: 1) depending on Geostationary Earth regional radiative effects of the 2002 El
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produce multiple-sky condition 2000 to January 2002, and Aqua Beta1 is Grant Matthews (Imperial College, outputs including clear-sky with and now available for September and London) presented the status of the without aerosol, and all-sky with and October 2002. Overall, validation GERB instrument which was launched without aerosol for multiple-cloud results are encouraging and a roadmap in August 2002 aboard the Meteosat conditions; and 2) include a new for improving known deficiencies is in Second Generation (MSG) satellite. inhomogeneous cloud optical depth place. The GERB experiment is a cooperative solver. Code structural modifications project between U.K., Belgian, and have been introduced which reduce Data Management Italian scientific institutions and was execution time for Surface and Atmo- built and calibrated in the U.K. It is the sphere Radiation Budget (SARB) by Mike Little (LaRC) reported on the first instrument to measure the about 40%. status of science data products, broadband SW and LW radiation processing environment, and technol- budget from a geostationary platform. Angular Distribution Models ogy advances. TRMM data processing GERB produces a radiation budget is complete until the next major map every 15 minutes at a spatial Norman Loeb (Hampton University) reprocessing. Terra Edition2 is com- resolution of 40 km x 40 km which will presented results of TOA radiative-flux plete through the end of 2002. A be enhanced to 10 km x 10 km using estimation from CERES ADMs. Early combined Terra/Aqua Edition1 data from Spin Enhanced Visible results from Terra ADMs show product is planned. Several hardware InfraRed Imager (SEVIRI), a high improvement over those from TRMM, changes are underway to improve the spatial resolution imaging instrument especially outside the Tropics. Final environment for development and also flying aboard the MSG. GERB Terra ADMs based on 2 years of testing of science codes and provide processing is using many of the data CERES/Terra rotating azimuth plane computing capacity for unscheduled reduction procedures developed for (RAP) measurements will be completed requirements. In the longer term, CERES. Design lifetime of a GERB in September 2003. More work is software may be converted to operate instrument is 3-5 years. needed to evaluate the quality of 1°- in an open source (LINUX) environ- resolution SW clear land ADMs and fits Takmeng Wong (LaRC) and Zachary ment to improve efficiency. James for ocean LW ADMs. SW and LW Eitzen (Colorado State University) Koziana (SAIC) briefed the team on ADMs are not yet developed for clouds presented results from a study of cloud ordering data from the Atmospheric over land and desert. Part I of a journal systems motivated by the desire to Sciences Data Center (ASDC) and on paper describing CERES/TRMM SW, better understand cloud-radiative subsetting CERES data products. LW, and WN ADMs was published, feedbacks in the climate system and Michelle Ferebee (LaRC) reported on and Part II summarizing TRMM ADM reduce uncertainties in the simulation the status of the ERBE Digital Library validation results was accepted. of cloud-radiation interactions in the being developed at the ASDC. Another paper on the use of neural global climate models (GCMs). This networks for TOA flux estimation was study involved analysis of the subgrid- Educational Outreach also accepted. scale characteristics of clouds obtained from the CERES cloud processing Lin Chambers (LaRC) reported that the Cloud Algorithms and Results system and comparing them with CERES Students’ Cloud Observations results of simulations from models Patrick Minnis (LaRC) summarized On-Line (S’COOL) project now has driven by meteorological input data cloud system results and validation for 1450 participating schools in 62 from the European Centre for Medium- Terra, and algorithm improvements countries. The 5th annual S’COOL Range Weather Forecasts (ECMWF). and initial results for Aqua, and teacher workshop will be held in June. CERES/TRMM cloud retrievals for required algorithm enhancements for The latest S’COOL newsletter was March 1998 (strong El Niño) and March handling multi-layer clouds, polar distributed in March in English, 2000 (weak La Niña) were analyzed. clouds, and partly-cloudy pixels. French, and Spanish. Probability density functions and other TRMM Visible-InfraRed Scanner (VIRS) statistics were derived for TOA SW Edition2 processing is complete, Terra Invited Presentations flux, outgoing LW, TOA albedo, cloud Edition1a has been run for February
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optical depth, liquid water path (LWP), basis using surface-measured fluxes showed that a threshold method ice water path (IWP), and other cloud from a number of different climate generally overestimated the cloud parameters. Cloud-height distributions regimes. Kratz concluded that clear- cover, underestimated the optical for tropical deep convective systems sky and all-sky LW fluxes meet the depth, and overestimated the droplet were found to be very different for El stated accuracy goal of ±20 Wm-2 radius. Niño and La Niña conditions. Cloud considered desirable for climate Bing Lin (LaRC) presented results from top height and LW distributions were research applications. Clear-sky SW a study of liquid/ice water paths and found to be insensitive to sea surface fluxes showed good agreement, but all- the vertical structure of clouds as temperature changes above 301 K. sky fluxes showed a large scatter observed from instruments aboard the caused by cloud spatial variability. Xiquan Dong (University of North TRMM satellite by comparing cloud Efforts are underway to improve the Dakota) presented validation of cloud properties retrieved from VIRS and all-sky SW comparisons. properties derived by the LaRC cloud TRMM Microwave Imager (TMI) data. group from Terra Moderate Resolution Gerald (Jay) Mace (University of Utah) VIRS-based retrievals came from Imaging Spectroradiometer (MODIS) presented results from a case study of CERES processing; Lin’s microwave data against ground-based measure- the evolution of a cirrus anvil based on radiative transfer model was used to ments from the Atmospheric Radiation satellite, aircraft, and surface-based analyze the TMI data. For comparison, Measurement (ARM) Southern Great observations on July 16, 2002, during VIRS cloud products were convoluted Plains (SGP) and North Slope of Alaska the Cirrus Regional Study of Tropical to match the larger TMI fields-of-view. (NSA) sites. Comparisons at the SGP Anvils and Cirrus Layers - Florida Area CERES/VIRS and TMI LWP retrievals site were presented for the period from Cirrus Experiment (CRYSTAL-FACE). for warm clouds were found to be in November 2000 to December 2001. Geostationary Operational Environ- very good agreement. VIRS overesti- Two methods were used for averaging mental Satellite (GOES) data provided mation of IWP for high clouds was satellite retrievals. For the first the temporal context while aircraft and attributed to the presence of low clouds method, data were averaged over a 30- surface data provided vertical cross underneath the cirrus layers. km x 30-km area centered on the site. sections. Mace concluded that com- Robert Cess (State University of New For the second method, data were bined observations like these should be York, Stony Brook) analyzed the impact averaged along a 3-km wide wind strip used to derive cloud properties and to of clouds on the radiation budgets of 19 over one hour centered on the time of examine the statistics of the empirical atmospheric GCMs. He expressed satellite overpass. Wind speed and relationships for different cloud types concern that a dozen years ago the direction were obtained from the and events. estimated temperature response to CO ECMWF data. Dong found that the 2 James Coakley (Oregon State Univer- wind strip method was more successful doubling among the models varied by sity) presented results of a new method at detecting clouds. Cloud heights a factor of 3, and the situation has not for retrieving cloud properties from showed good agreement for solid changed much since then. He com- partially cloud-filled pixels. He stated cirrus and mid-level clouds. For pared the effects of clouds in 19 GCMs that partially cloud-filled pixels occur stratus clouds, wind strip average against results from multi-year 3- even at the highest spatial resolution values of particle size agreed well with month averages of SW, LW, and net (including 1-km MODIS data). Cloud surface data, but optical depth and cloud radiative forcing (CRF) from properties derived from these pixels LWP values were much lower. ERBE observations. For zonal aver- with a clear/overcast threshold method ages, most models underestimated SW Investigator Presentation Highlights are subject to significant errors. The CRF while LW CRF compared better. David Kratz (LaRC) presented valida- partially cloudy method is based on Averages of net CRF over a 60N-60S tion of Terra Single Scanner Footprint adjusting the cloud amount, optical domain agreed well for some models (SSF) surface-only SW and LW fluxes depth, and droplet radius to ensure a but not for others. Comparisons of net derived using TOA-to-surface transfer match between computed and ob- CRF over the Pacific Ocean showed algorithms and fast radiation served radiances at 0.64, 3.7, and 11 µm. that some models compared better over parameterizations. Validation was Coakley’s results for several scenes of the eastern region while others did done on an instantaneous/footprint VIRS 2-km data and MODIS 1-km data better over the western region. Com-
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parisons of clear-sky reflected SW flux tions. early February 2003 and became fully and outgoing LW showed disturbingly operational in April. Viollier also large differences between the models Ron Welch (University of Alabama in discussed the status of Megha- and relative to ERBE values. Huntsville/UAH) presented compari- Tropiques, a cooperative Indo-French sons of CERES- and MODIS-derived mission which will carry two passive Anand Inamdar (Scripps Institution of cloud masks over the ARM/NSA site microwave instruments and a radiation Oceanography) presented a study of with various ground-based measure- budget instrument in a low-inclination the atmospheric LW cooling over ments. Large differences were found orbit for studying tropical water and tropical oceans inferred from CERES/ between CERES mask and surface energy cycles. TRMM data. He analyzed TRMM/SSF estimates, particularly for high, thin data to demonstrate the magnitudes of clouds. The MODIS algorithm gener- Nicolas Clerbaux (Royal Meteorologi- LW cooling separately for the WN and ally detected more high, thin clouds cal Institute of Belgium, RMIB) non-window regions. Specifically, than the CERES algorithm but some- reported on the status of activities at imager-based surface skin temperature, times found clouds where surface data the RMIB where high spatial and microwave precipitable water vapor indicated clear skies. temporal resolution TOA radiative over oceans, outgoing LW, outgoing fluxes will be produced using observa- WN flux, and downward broadband Qingyuan Han (UAH) identified two tions from a geostationary platform. and WN fluxes were analyzed. important sources of uncertainty in the This will be accomplished with a Corresponding non-window quantities retrieval of ice cloud properties. The coordinated use of data acquired by the were computed from the broadband first is the use of empirical particle size GERB and SEVIRI instruments aboard and WN values. Inamdar presented distributions. He suggested that the the MSG satellite. A resolution plots of WN and non-window surface use of theoretical size distributions enhancement technique will be used to and atmospheric cooling effects as greatly reduces the large uncertainties connect the broadband GERB flux functions of sea surface temperature in single scattering properties. The retrievals to 10 km x 10 km blocks of and column precipitable water vapor. second source of uncertainty was the SEVIRI pixels. use of a single crystal habit (shape) by Shi-Keng Yang (NOAA National Thomas Charlock (LaRC) presented an many retrieval algorithms. For Centers for Environmental Prediction, assessment of the direct aerosol forcing example, the CERES algorithm NCEP) presented an analysis of the (DAF) of TOA, surface, and atmo- assumes ice particles to be hexagonal trends in tropospheric humidity in the spheric radiative fluxes for clear- and columns, ISCCP algorithm assumes NCEP/National Center for Atmo- all-sky conditions. Clear-sky results them to be polycrystal, and MODIS spheric Research (NCAR) reanalysis were presented for a month (April algorithm assumes a combination of during the pre-satellite period (1949- 1998) and all-sky results for a day (June three shapes. These assumptions lead 1978). He showed that TOA LW CRF in 17, 1998). He found good agreement to large uncertainties in effective the reanalysis continually decreased for April 1998 between DAF values at particle size, single scattering proper- during this period and was related to the TOA for tuned clear-sky fluxes and ties, as well as cloud emissivity and the decrease in 500 hPa relative for CERES observations. Charlock albedo. Han suggested that more humidity. Yang also analyzed TOA and used Global Aerosol Climatology realistic habits could be derived using surface radiative fluxes from the latest Project data to show the distribution of CERES RAP observations. Atmospheric Model Intercomparison aerosol optical thickness (AOT) Project (AMIP) simulations at NCEP, Michel Viollier (Laboratoire de differences between April 1998 and that used the current global forecast Meteorologie Dynamique, France) April 1989 to contrast an El Niño year model. He concluded that the current compared CERES/Terra and early (1998) with a non-El Niño the Southern NCEP global forecast model was not GERB measurements with broadband Hemisphere (SH) and lower AOT in the able to simulate the ERBE and CERES fluxes derived from POLarization and Northern Hemisphere (NH) during observations well. Like many other Directionality of Earth’s Reflectances April 1998, and suggested that the El GCMs, it did not reproduce the decadal (POLDER) data by using narrowband- Niño may be causing a decrease variability of TOA radiation shown by to-broadband conversion algorithms. (increase) of AOT over the NH (SH) Wielicki et al. from satellite observa- POLDER-2 began providing data in oceans. Also, since most of the aerosol
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heating of the atmosphere occurs in the Radiometer, AVHRR) algorithms while Aerosol Robotic Network (AERONET) NH, the April 1998 El Niño may be MODIS retrievals were made with a observations for March 2001. He found suppressing that atmospheric heating. multi-channel algorithm. Several that the differences of AOT at both comparisons of both Terra and Aqua wavelengths (0.659 and 1.64 µm) were Alexander Ignatov (NOAA National retrievals for AOT at 0.659 and 1.64 µm, caused primarily by cloud contamina- Environmental Satellite, Data, and and the Angstrom exponent, Å, were tion of the clear footprints used in Information Service, NESDIS) com- shown. The two products showed retrievals. Reducing the effects of pared aerosol optical properties good agreement. cloud contamination on the retrievals retrieved over the oceans as a part of brought the results of the two algo- CERES processing with corresponding T. Zhao (NOAA/NESDIS) examined rithms close to each other and to the MODIS retrievals. CERES retrievals the differences of AOT and Å, retrieved AERONET observations. were made with single channel (like the with AVHRR-like and MODIS algo- Advanced Very High Resolution rithms, and also compared them with
CERES measured the thermal energy or heat emitted from the United States, as shown in this image from May 2001. The record-setting high temperatures experienced in Southern California and Nevada on May 9 are visible in the light areas where great amounts of thermal energy are escaping to space. This example illustrates one of the most basic stabilizing forces in the Earth's climate system: clear hot regions lose more energy to space than cold areas. The regions of low thermal emission over the northern U.S. are cold cloud tops. CERES data will be used to verify the ability of climate models to accurately predict this emission as our world experiences changes in surface reflectivity, clouds, atmospheric temperatures, and key greenhouse gases such as water vapor.
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Summary of the Joint CloudSat/CALIPSO Science Team Meeting
— Debra Krumm, [email protected], Colorado State University — Kim Cannon, [email protected], NASA Langley Research Center — Deobrah Vane, [email protected], Jet Propulsion Laboratory — Pat McCormick, [email protected], Hampton University, something
A joint CloudSat/Cloud Aerosol Lidar mission. The five satellites mentioned State University (CSU), Jet Propulsion and Infrared Pathfinder Satellite above will eventually be joined by a Laboratory (JPL), Canadian Space Observations (CALIPSO) Science Team sixth, the ESSP-sponsored Orbiting Agency, the U.S. Air Force, U.S. meeting was held March 3-6, 2003, in Carbon Observatory (OCO). Department of Energy, Goddard Space Broomfield, CO, and was chaired by Flight Center and scientists from CloudSat Mission the respective Principal Investigators France, United Kingdom, Germany, (PIs), Graeme Stephens (Colorado State CloudSat will carry a special type of Japan and Canada. For additional University) and Dave Winker (NASA- high frequency radar (94 GHz). This information, the CloudSat website is: Langley Research Center). The cloud-profiling radar (CPR) will cloudsat.atmos.colostate.edu/. CALIPSO and CloudSat satellites are provide the vertical distribution of CALIPSO Mission co-manifested on a Delta II, scheduled cloud physical properties including for launch in November 2004. Many of liquid water content, ice content, and CALIPSO will carry a two-wavelength, the science team members belong to cloud optical depth [Stephens et al., polarization lidar and two passive both missions, and much of the science 2002]. The CloudSat mission is a instruments to provide an opportunity return and many of the scientific cooperative effort that includes its for more comprehensive atmospheric operations are of interest to both international partner, Canada, and its data collection on aerosols and opti- groups. The meeting was well attended industry partner, Ball Aerospace and cally thin cirrus. Lidar is similar to and participant feedback indicates the Technologies Corporation. Among radar but sends pulses of light gener- meeting was very successful. Another CloudSat’s other partners are Colorado ated by a laser through the atmosphere, joint Science Team meeting will be planned as the missions near launch.
Afternoon Constellation (‘A-Train’)
CALIPSO and CloudSat are NASA Earth System Science Pathfinder (ESSP) missions and will become part of the Afternoon Constellation (known informally as the “A-Train” after the famous jazz tune “Take the A-Train,” by Billy Strayhorn—See NASA Facts, FS-2003-1-053-GSFC for additional information). The other satellites in the polar-orbiting constellation are Aqua, Aura, and Polarization and Anisotropy of Reflectances for Atmospheric Science Coupled with Observations from a Lidar (PARASOL), a French Centre National d’Etudes Spatiales (CNES) Figure 1: The Cloud Aerosol Lidar and Infrared Pathfinder Sallite Observations (CALIPSO) Satellite
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where a fraction is then scattered by aerosols and cloud particles back to the instrument . The CALIPSO satellite will provide vertical profiles of aerosols and clouds using the first satellite lidar dedicated to atmospheric sensing [Winker et al., 2003]. The lidar will observe the vertical distribution of aerosols and clouds and the passive instruments will provide additional information on particle properties, improving our understanding of the role aerosols play in Earth’s climate Figure 2: The A-Train satellite constellation. system. The CALIPSO mission is a Tuesday, March 4 competitions, checkers was chosen as cooperative effort led by NASA’s the ‘sport event.’ Traditionally, the Langley Research Center (LaRC) and Tuesday morning kicked off three days CloudSat Cup pits the engineers includes the French space agency of joint CloudSat/CALIPSO sessions against the scientists and traditionally, CNES, Hampton University, Ball with a welcome from the Mission PIs the scientists led by Graeme Stephens Aerospace and Technologies Corpora- and opening remarks from Don have won. Congratulations to the tion (Ball), and the French Institut Anderson. Tuesday’s joint session engineers, led by Tom Livermore, who Pierre Simon Laplace. For additional included project status reports by emerged victorious for the first time in information, the CALIPSO website is: CALIPSO and CloudSat project four years—unfortunately the coveted www-calipso.larc.nasa.gov. management. John Rogers (LaRC), the CloudSat cup disappeared during the CALIPSO Project Manager, highlighted evening. Joint CloudSat/CALIPSO Science the recently approved project replan. Team Meeting Mark LaPole (Ball), the CALIPSO Wednesday, March 5 Monday, March 3 Payload Manager presented the status of the payload, highlighting progress in Wednesday morning, Joint Session IV, The first day of the meeting was a each of the payload components. Tom addressed the progress in global focused CALIPSO Science Team Livermore (JPL), the CloudSat Project climate modeling and data assimilation session, which included presentations Manager, gave an overview of project and took advantage of the local on recent characterization test results status and Randy Coffey (Ball), the expertise at NCAR and CSU, as well as for the lidar detector and the status of CloudSat Spacecraft Manager, pre- the international mission participation Level 2 lidar algorithms. This session sented an overview of the spacecraft, from CloudSat and CALIPSO. This was adjourned for a tour of CALIPSO highlighting recent progress in devel- theme continued during the afternoon and CloudSat hardware at the nearby opment. John Stadler (LaRC), the in Joint Session V that consisted of Ball facility in Boulder. The meeting CALIPSO Systems Engineer, discussed special reports on other missions. reconvened that evening with a joint changes to the on-orbit formation to Didier Tanre (Laboratoire d’Optique CloudSat/CALIPSO town hall session minimize impacts of sun glint on the Atmospherique/Centre National de la to discuss strategy for a NASA Re- overall science objectives. The rest of Recherche Scientifique), PI on PARA- search Announcement (NRA) as well as the morning and afternoon were SOL, brought everyone up to date on concepts for the next mission. The dedicated to updates of the science PARASOL and its instrument, Polariza- Mission PIs, Graeme Stephens (CSU) algorithms and descriptions of data tion and Directionality of Earth and Dave Winker (LaRC), and Earth products (Joint Session III). A reception Reflectances (POLDER 2). Pedro Science Enterprise (ESE) Program held Tuesday night at the Omni was Baptista (ESA/ESTEC) discussed Manager for Radiation Science, Don the site of the now infamous CloudSat EarthCare simulation, and Francisco Anderson (NASA Headquarters—Code Cup Competition. Because of the Valero (Scripps Institution of Oceanog- YS) led the discussion. number of injuries during previous raphy/UCSD) gave an overview of
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Learning and Observations to Benefit the Environment (GLOBE) program.
The final day returned to the validation theme with several more presentations, and the meeting concluded with a session on one of the groundbreaking aspects of these two missions, combin- ing multi-sensor data (Joint Session VIII). Combining sensors achieves synergy, meaning more information about the Earth will be obtained from the combined observations of the different satellites and their instru- ments as a formation, than would be possible from the sum of the observa- tions taken independently. Achieving synergy between the missions will also be one of the most difficult engineering aspects of the two missions and the remaining presentations highlighted the promise and potential of these synergistic observations.
References Figure 3: The CloudSat Satellite Stephens, Graeme L., Deborah G. Vane, Deep Space Climate Observatory Thursday, March 6 Ronald J. Boain, Gerald G. Mace, (DSCOVR—formerly Triana). Kenneth Sassen, Zhien Wang, Anthony Validation is a topic of extreme The final day of the meeting began J. Illingworth, Ewan J. O’Connor, importance to any mission, and the with CALIPSO taking credit for the William B. Rossow, Stephen L. Durden, Validation Activities session was the CloudSat “cupnapping.” A ransom Steven B. Miller, Richard T. Austin, focus for the remainder of this meeting. note was delivered shortly after the Angela Benedetti, Cristian Mitrescu, Among the current and future cam- meeting and it is believed that the and the CloudSat Science Team. 2002. paigns and field experiments that were CloudSat Cup is currently on a world- The CloudSat Mission and the A-Train: A discussed and offer potential benefit to wide tour until those demands are met. New Dimension of Space-Based Observa- CloudSat and CALIPSO were the The morning presentations began with tions of Clouds and Precipitation. Bulletin Cirrus Regional Study of Tropical a break from validation. The CALIPSO of the American Meteorological Anvils and Cirrus Layers Florida Area Co-PI, Pat McCormick (Hampton Society, vol. 83, number 12, pp. 1771- Cirrus Experiment (CRYSTAL-FACE), University), teamed with Debra 1790. December. the Tropical Western Pacific Campaign, Krumm (CSU), director of education Winker, David M., Jacques Pelon, and the Atmospheric Radiation Measure- and public outreach for CloudSat, to M. Patrick McCormick, 2003: The ment Program (ARM), MIRAI, Re- describe the cooperative plans that the CALIPSO mission: Spaceborne lidar for gional East Atmospheric Lidar Mesonet two missions have for reaching out to observation of aerosols and clouds. Proc. (REALM), and others. The validation the public and to students around the SPIE, vol 4893, pp. 1-11. activities of other satellite missions world in Joint Session VII. Students including Aura (another A-Train will be organized to collect data to member) and Terra were also pre- provide ground-based observations sented. through the NASA-sponsored Global
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ASTER Users Workshop
— Mike Abrams, [email protected], Jet Propulsion Laboratory
The Advanced Spaceborne Thermal (University of Arizona) and Simon Emission and Reflection Radiometer Hook (JPL). They described how (ASTER) Users Workshop was held calibration and validation of the ASTER April 28-29, 2003, in Arcadia, California instruments is done through analysis of data. They also described two ASTER- near the Jet Propulsion Laboratory on-board calibration lamps and their specific tools: the Global Visualization (JPL). Over 100 participants attended response; and through regular, inten- Viewer (GLOVIS), a tool for browsing the two-day workshop dedicated to sive field validation campaigns. Field images; and Data Pool, a tool to teaching users about ASTER data. The work involves selecting large, homoge- download data only over the US. first day of the workshop was devoted neous ground targets, such as dry to descriptions of the instrument, lakes, sand dunes, and lakes. The sites Larry Rowan (US Geological Survey calibration, data products, and data are occupied during instrument [USGS]) opened the second day of ordering tools. The second day was overpasses, and thoroughly instru- applications discussions, and talked devoted to presentations of scientific mented to measure surface radiative about using ASTER data for mineral applications. Speakers came from the characteristics, solar radiance, meteoro- mapping. He showed how to use U.S. ASTER Science Team, the Land logical conditions, etc. The measured shortwave infrared data with visible Processes Distributed Active Archive surface parameters are convolved with and thermal data to extract mineral Center (LPDAAC), the Japanese models, and the values are compared to spectral signatures, and described the Ground Data System, and the Univer- the instrument -measured values. limitations of the ASTER discrete sity of California Davis. Throughout bands. Tom Schmugge, U.S. Depart- the two days, participants had access to The next presentation was by Michael ment of Agriculture, described his internet-enabled workstations. With the Abrams, covering the ASTER data research into extracting surface energy- assistance of LPDAAC staff, they were products. ASTER provides 14 standard balance parameters by combining able to learn how to search and order data products; some are geophysical, ASTER data, field measurements, and ASTER data through the U.S. and Japan derived products, such as reflectance at analytical models. Simon Hook, JPL, data systems, explore the data through the surface. Each product is periodi- talked about lake studies using ASTER the Global Visualization (GLOVIS) tool, cally validated to verify performance of thermal data. His study site at Lake and order U.S. data through the Data the algorithms, and to look for instru- Tahoe illustrated using the data for Pool tool. ment anomalies. temperature monitoring, and lake circulation studies. Alan Gillespie, Michael Abrams, JPL, Associate The remainder of the afternoon was University of Washington, presented ASTER Science Team Leader, wel- devoted to descriptions of data several environmental applications, comed the participants and presented ordering and browsing tools available including determining ages of clear the agenda for the two-day workshop. online. Hiroshi Watanabe discussed cuts and forest regrowth, climatological Anne Kahle, JPL, ASTER Science Team the Japanese Ground Data System and studies in Tibet, and stream-tempera- Leader, presented an overview of the the browse and order capabilities ture determinations. Susan Ustin, ASTER instrument, the history of the offered through web sites. In addition, (University of California, Davis), ASTER project, and described the he described the scheduling and data described vegetation studies, focusing collaboration between the U.S. and processing done in Japan. Bryan Bailey, on agricultural crop monitoring and Japan. Bhaskar Rhamachandran, and Zheng classification using ASTER data in the Zhang from the Land Processes DAAC California Central Valley. Jeff Kargel, Radiometric calibration was covered by described the EOS Data Gateway web (USGS), presented a talk on the Global Stuart Biggar and Kurt Thome tool used in the U.S. to access all EOS Land Ice Measurements from Space
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(GLIMS) project, that is using ASTER Environmental Monitoring project he data to monitor thousands of glaciers leads. The goal of the project is to worldwide. The project is a collabora- characterize and monitor 100 cities tion between 24 international organiza- around the world using a variety of tions. Dave Pieri (JPL) spoke on data types. volcano monitoring using ASTER. Several unique capabilities were The workshop presentations are highlighted, including mapping SO2 available on CD. Please send your emissions, determining lava-dome request to [email protected] physical characteristics, and hot-spot mapping. Mike Ramsey (University of Pittsburgh) described the Urban
This image of Mt. Usu volcano is dominated by Lake Doya, an ancient volcanic caldera. On the south shore is the active Usu volcano. Friday, March 31, 2000, more than 11,000 people were evacuated by helicopter, truck, and boat from the foot of Usu. The volcano began erupting from the northwest flank, shooting debris and plumes of smoke streaked with blue lightning as high as 2,700 meters (8,850 feet) into the air. Although no lava flowed from the mountain, rocks and ash continued fo fall after the eruption. This was the seventh major eruption of Mount Usu in the past 300 years. Fifty people died when the volcano erupted in 1822, its worst known eruption.
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CCSDS Lossless Data Compression to be Available in HDF-4 and HDF-5
— Wei Xia-Serafino, [email protected], NASA Goddard Space Flight Center / GST — Ben Kobler, [email protected], NASA Goddard Space Flight Center —Pen-shu Yeh, [email protected], NASA Goddard Space Flight Center
EOSDIS manages data from NASA’s compression standard for international tion running the Unix operating past and current Earth science research space applications. This technique was system. The prototype study results satellites and field measurement developed specifically for science demonstrated that CCSDS lossless data programs, providing data archiving, instrument data through a joint effort compression was superior to the other distribution, and information manage- between NASA GSFC and the Jet techniques in compression ratio and ment services. Over two terabytes of Propulsion Laboratory (JPL), based on compression speed. Table 1 shows the data are being produced by the EOS requirements for high speed real time summary comparison results. Values in project each day. The transmission and processing, low complexity, and quick the table represent the averages over all archiving of such an unprecedented adaptation to statistics. It has been the science data products tested. amount of data requires tremendous implemented for many space missions processing time, computer storage, and in both instruments and data systems Between 1999 and 2001, a further study I/O bandwidth. One technique that can and base-lined for many future on the feasibility of using CCSDS reduce data storage and network satellites as well. compression for real-time processing of requirements without compromising EOS data was performed. Gigabytes of data fidelity is lossless data compres- In 1998, the Earch Science Technology MODIS real sensor data were tested on sion. Office (ESTO) / Earth Science Data and an EOS Core System (ECS) operational Information System (ESDIS) supported machine. The results showed that the The most commonly used lossless data a prototype study to evaluate the Sz compression time on the ECS compression techniques are based on performance of these different data production machine for a typical set of the Lempel-Ziv-77 (LZ77) algorithm compression techniques applied to EOS MODIS products (one granule includ- (e.g., gzip or its variations). This data. The performance of different ing 1-km, 500-m and 250-m resolution technique, however, generally yields lossless data compression techniques data) was about 3 minutes. In compari- poor compression ratios on data was compared on typical EOSDIS son, it took almost one hour to com- originating from spacecraft instru- HDF-EOS data files. Two measure- press the same data sets using Gzip. ments. A second well-established ments, speed and compression ratio Only the Sz compression speed was technique is arithmetic coding (e.g., (CR), were used as the comparison suitable for the ECS operations, since JPEG arithmetic coding). This tech- criteria. The algorithms evaluated were the compression time per granule nique works on most types of data, but the CCSDS lossless data compression would be relatively small (~10%) exhibits relatively slow speed due to (Sz), Gzip (Gz), Unix compress (Cz), compared to the time required to the need to update statistics during the and JPEG Arithmetic coding (Az). They generate one granule of Level-1B data process. The Consultative Committee were tested on a Sun Sparc20 worksta- from Level 0 data. A scalability analysis on Space Data Systems Table 1. Phase I Result Summary (CCSDS) has adopted the Sz Gz Cz Az extended-Rice CR 3.24 2.44 2.06 2.38 algorithm as the Compress (seconds) 353 8112 1973 10516 recommended Decompress (seconds) 394 1264 790 7341
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model was established by Daniel After two years of collaboration Menasce (George Washington Univer- between NASA, NCSA, and the sity) to assess the cost savings of using University of Idaho (the current license CCSDS lossless data compression in the holder of the Sz license), CCSDS ECS operational system. The analysis lossless data compression will now be was done based on the data volumes incorporated into HDF. HDF-5 Release archived and distributed at the GSFC 1.6, to be released in June, 2003, will DAAC. The scalability model was include support for CCSDS lossless used to assess cost savings of using Sz data compression (Sz), along with the as a data compression algorithm in two supporting utility programs. The next scenarios: (1) SZDC - compress before release of HDF-4, to be released in storing and distribute in compressed summer 2003, will also include support form; and (2) SZDU - compress before for Sz. storing and uncompress before distributing. SZDC saves bandwidth Pre-configured and pre-compiled HDF and network transmission time over binaries will have Sz enabled, and will SZDU but requires users to decompress support data sets with 1-24 bits/pixel, files. It was determined that substantial 32 bits/pixel, and 64 bits/pixel. Sz cost savings could result from the use source code and Sz binaries will also be of hardware tape compression (1.5:1 available for download from NCSA. compression) for Level 0 data products, Applications will enable Sz by setting and Sz compression for Level 1 and an optional filter when a dataset is higher data products. created. Once enabled, data will be automatically compressed and decom- Based on the results, ESDIS recom- pressed with Sz during I/O. Sz mended implementing the lossless data distributed with HDF products will be compression algorithm, Sz into the free for non-commercial use, to both National Center for Supercomputing encode (compress) and decode Applications (NCSA) Hierarchical Data (uncompress) data. Commercial users, Format (HDF) library. EOSDIS uses however, may use the software only to HDF-EOS, an extension to HDF, for decode data, and will need to acquire archiving and distributing EOS data. commercial licenses to distribute an Sz- HDF includes I/O libraries and tools based encoding software product. for analyzing, visualizing, and convert- ing scientific data. The current version Further details on Sz usage will be of HDF-4 already supports lossless data available from the NCSA HDF web site. compression algorithms – Run Length Encoding (RLE), Skipping Huffman (SKPHUFF), and Gzip compression (Lempel/Ziv-77 dictionary coder, named Deflate). The current version of HDF-5 supports Gzip compression only. Implementing the CCSDS lossless data compression into the HDF library provides a transparent method for users to capitalize on reduced data volumes since the HDF library contains an interface for storing and retrieving compressed or uncompressed data.
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Aqua Mission Sponsors 2003 Engineering Competition
— Steve Graham, [email protected], Aqua Outreach Coordinator, Goddard Space Flight Center — Claire Parkinson, [email protected], Aqua Project Scientist
On April 26, 2003, the Aqua Project analyzed, sorted, and crunched data very impressive teams. In addition to Science Office, along with the NASA using their problem-solving skills, then the first and second place awards, Palm Goddard Space Flight Center Educa- used a laptop to make a final Pilots, shirts, and well-deserved tion Programs Office, EOS Mission PowerPoint presentation to the judging trophies were given to all members of Operations Office, Morgan State panel. all five finalist teams. University, DuVal High School, and the Baltimore Museum of Industry, After the presentations were made, all NASA congratulates all the teams for sponsored the Aqua Engineering the teams, parents, judges and facilita- impressive performances during an Competition for High School students. tors made their way across the street to enjoyable day of competition and The competition consisted of two the Goddard Visitor Center where education. Many thanks to the follow- rounds of problem solving, a qualifying everyone was treated to lunch and ing key contributors for all their hard long-term problem where teams had 10 presentations by the sponsoring work: Claire Parkinson, Aqua Project weeks to solve a real-world Aqua agencies. Meanwhile, the judges were Scientist; Ken Anderson, Aqua Engi- problem, and a short-term hypothetical hidden away to tally up the round two neer; Steve Graham, Aqua Outreach problem that had to be solved in 90 scores and ultimately determine the Coordinator; Ron Erwin, Goddard minutes. winners. At the end of the day, all the Education Programs Office; Ana teams and parents were treated to a Swamy, Morgan State University; In the competition’s first round, teams personal tour of the EOS Mission Eugene Hoffman, Morgan State from within Goddard’s service region Operations Center, hosted by Paul University; Dereje Seifu, Morgan State (Washington D.C. to Maine) were asked Ondrus, the EOS Mission Operations University; Susan Maule, Baltimore to determine the likely cause of a Director. Museum of Industry; Lynn Hardin, sudden increase and decrease that DuVal High School; and finally Paul occurred in Aqua’s solar array current The Grand Prize, a state-of-the-art PC Ondrus, EOS Mission Operations and resulted in the spacecraft entering or Apple Macintosh computer system Director, for graciously providing the into “safe mode” during its first month complete with a large assortment of funding for the competition. of operation. A total of 12 entries were supporting software, was awarded to received and evaluated and the top five the six-member team of Perry Hall teams were selected as finalists. These High School in Baltimore, Maryland. finalists were then invited to DuVal The First Runner-Up team, from the High School for the second and final Applications and Research Laboratory round of the competition, which High School (Red Team) of Ellicott City, occurred on April 26. Four high school Maryland, was also awarded a PC or teams from Maryland and one team Apple Macintosh system with software. from Connecticut were the five finalists and were tasked with determining how Tourtellotte Memorial High School of best to operate a supposed malfunc- Grosvenordale, Connecticut, placed a tioning Solid State Recorder (SSR), very impressive third, and Chopticon including calculations for data loss High School of Morganza, Maryland, based on specific SSR temperatures and and DuVal High School of Lanham, bit error rates. The five finalist teams Maryland, rounded out the field of
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SEEDS Update
— Kathy Fontaine, [email protected], NASA Goddard Space Flight Center
The Strategic Evolution of Earth (ESIP) Federation were involved in William Johnston, senior scientist at Science Enterprise Data Systems every study team, and contributed Lawrence Berkeley National Labora- (SEEDS) group held its third public greatly to the development of the tory, who spoke about the Global Grid workshop in Annapolis, Maryland, on recommendations. While the formal Forum standards development process; March 18–20, 2003. With nearly 100 in comment period has expired, the draft Cheryl Craig from the HIRDLS project, attendance, from government agencies, is still available via the SEEDS who spoke from the science team private industry, and universities, this homepage (lennier.gsfc.nasa.gov/seeds/ perspective about lessons learned in was our most well-attended and index.html), and comments are always developing standards; and Joseph successful workshop to date. The two welcome. Coughlan from NASA Ames Research primary goals of this workshop were Center, who talked about technology to: Eighty-nine items were sent in over the infusion efforts in his organization. All course of the four months that the presentations from this workshop are 1) give the data provider and recommendations were officially open available via the link to the third science user communities the for comment. Comments ranged from workshop. opportunity to respond in general agreement or disagreement person to the draft set of with certain points to specific wording For the Formulation Team, work recommendations prepared suggestions. All comments are continues. After completing the Draft by the SEEDS Formulation currently being processed, and answers Recommendations Document, the team Team; to each comment will be sent back to will be busy welcoming the Research, 2) and to begin dialog on the the originator. Education, and Applications Solutions next phase of formulation: Network Cooperative Agreement preparation for implementa- Notice (REASoN CAN) awardees to the Mary Cleave, Deputy Associate tion of a SEEDS Program working groups, finalizing their Administrator for Earth Science Office. charters, and beginning their work. We (Advanced Planning), opened the are also planning for a workshop in the meeting with a presentation about The draft set of recommendations was fall to welcome the REASoN winners Code Y’s plans for the next decade. reported in the November / December and bring them up to speed on SEEDS. 2002 Earth Observer, and stems from the Martha Maiden, Program Executive, work of seven study teams who were presented the status of the data tasked to look at a specific aspect of roadmap being created by Code Y as a data systems in a distributed, heteroge- way to link data activities to research, neous environment (namely, levels of applications, missions, and other Code service, standards for near-term and Y activities. Then Stephen Wharton, longer-term missions, data lifecycle and SEEDS Formulation Manager, pre- long-term archive, reuse, and reference sented his goals for the workshop. architectures, technology infusion, and Other invited speakers included Dave metrics planning and reporting). Each Jones, President of the ESIP Federation, study team had a set of objectives and who spoke about Federation goals and assembled a team representative of areas for cooperation with SEEDS; data-service providers, users, and other David Etter from the Bay Area Shared data-systems experts. Members of the Information Consortium (BASIC), who Earth Science Information Partner presented his work on standards;
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Kudos
Glaciers and a Stream Named for EOS Scientists
Feature Name: Bindschadler Glacier Latitude: 77º58´S; Longitude: 162º09´E Description: A glacier in the Northwest part of Royal Society Range, Victoria Land, flowing north between Table Moun- tain and Platform Spur to join Emmanuel Glacier. Named by US-ACAN in 1992 after glaciologist Robert A. Bindschadler of the NASA Goddard Space Flight Center; from 1983 a principal investigator for the United States Antarctic Research Program (USARP) studies of the West Antarctic Ice Sheet, including dynamics of ice streams in the Siple Coast area, their interaction with the Ross Ice Shelf, and the role of polar ice sheets in global climate change. Bindschadler is a member of the Landsat TM Instrument Team.
Feature Name: Bindschadler Ice Stream Latitude: 81º00´S; Longitude: 142º00´W Description: An ice stream between Siple Dome and MacAyeal Ice Stream. It is one of several major ice streams draining from Marie Byrd Land into the Ross Ice Shelf. The ice streams were investigated and mapped by USARP personnel in a number of field seasons from 1983-84 and named Ice Stream A, B, C, etc., according to their position from south to north. The name was changed by US-ACAN in 2002 to honor Robert A. Bindschadler.
Feature Name: Shuman Glacier Latitude: 75:154S; Longitude: 139:304W Description: Glacier about 6 miles long draining through the Ruppert Coast north of Strauss Glacier. Named by US- ACAN after Christopher A. Shuman, NASA Goddard Space Flight Center, Greenbelt, MD, a field and theoretical researcher in the West Antarctic Ice Stream area from the 1990s to present. Shuman is a member of the IceSAT Instru- ment Team.
The Earth Observer staff and the entire science community wish to congratulate Drs. Bindschadler and Shuman for these outstanding accomplishments.
National Academy of Sciences Election
The National Academy of Sciences recently announced the election of 72 new members and 18 foreign associates from 11 countries in recognition of their distinguished and continuing achievements in original research. Among those honored was Judith L. Lean, a research physicist in the space science division of the Naval Research Laboratory, Washington, DC. Lean is a member of the SORCE Science Team.
The Earth Observer staff wishes to congratulate Dr. Lean on this outstanding accomplishment.
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Earth’s Hidden Waters Tracked by GRACE
— Alan Ward, [email protected], EOS Project Science Office, NASA Goddard Space Flight Center / SSAI
The Gravity Recovery and Climate availability, quality, and conservation also depend on soil moisture and Experiment (GRACE) mission, the first issues impact every nation on Earth surface water. Furthermore, groundwa- Earth System Science Project (ESSP) and are becoming ever more important ter sustains streams between episodes mission launched by NASA in March of as population increases and other of surface runoff, and snowmelt 2002, will produce extremely accurate natural and manmade changes place recharges the other stocks of water. maps of the Earth’s gravity field. This more and more demand on these information may be used to track changes precious resources. Surface water Since water availability is such a vital in continental water storage on a global includes both flowing water in streams societal need, it is very important to scale. GRACE is able to sense changes in and rivers, and impounded water in better quantify water storage changes the Earth’s gravity field over a given time soil (soil moisture), natural lakes, polar over the continents, particularly period. Changes in the Earth’s gravity field ice caps, and manmade reservoirs. It changes in groundwater storage. For arise in response to changes in the mass also includes important seasonal example, it is well documented that the distribution both on and beneath the variations caused by annual snowfall. water level of the High Plains aquifer, Earth’s surface. It turns out that water Groundwater is the other component of which encompasses a large portion of movement (both of surface water and total water storage and includes the the Midwestern U.S., has been steadily groundwater) is one of the major causes of large amounts of water stored beneath declining for the past few decades and fluctuations in mass on the Earth’s surface. the Earth’s surface in aquifers. Besides it is believed that similar scenarios are Thus, if the effects of other causes of mass supplying water for drinking and other playing out all over the world. The change (the atmosphere, the oceans, and domestic uses, surface and aquifer culprit is overuse; more water is taken rebound from the weight of glaciers) can be waters are essential for power genera- out each year to meet the growing removed, one should be able to deduce tion and irrigation. Plants and animals needs of society than is replenished by water storage changes over the continents from a gravity measurement. Introducing additional model information on soil moisture and other components of the total water storage may allow for the portion of the total water storage change attributable to groundwater (aquifer) changes to be isolated, which could be extremely useful in places where monitoring networks are sporadic or nonexistent and be a very powerful new tool for applications such as water resource planning.
Introduction
Viewed from above, our home planet is a “blue marble” with an abundance of water on its surface. Yet, only a small amount of this water is fresh and Figure 1: The pie graph shows that only a very small portion of the Earth's water is fresh. The closeup suitable for consumption by plants, shows the breakdown of the fresh water supply. Almost a third of the world's fresh water is groundwater — stored in underground aquifers. Hence, GRACE's expected ability to monitor changes animals, and humans. Potable water in these unseen water reserves from space is very significant.
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atmosphere, oceans, continents, glaciers, and polar ice caps. GRACE will reveal the broad features of the Earth’s gravitational field over land and sea; it will also allow for these smaller scale features to be identified and studied with unprecedented accuracy and it will show how the Earth’s gravity field varies with time. The unique design of the GRACE mission is expected to lead to an improvement of several orders of magnitude in these gravity measure- Figure 2: This graph shows that agriculture places the largest demand on the world's available water ments and allow much improved resources. Many agricultural applications draw their water from underground supplies. The continued viability of agriculture in some areas of the world critically dependent on these aquifers. resolution of the broad to finer-scale features of Earth’s gravitational field nature. To date, however, the influence moisture from orbit and will result in over both land and sea. of climate and meteorological phenom- improved representation of surface soil The Earth’s gravity field consists of two ena on water storage changes is not water storage in models. However, it is components: a mean (or long term well understood, and as a result unable to penetrate beyond the top few average) component and a time models still do a poor job of represent- centimeters to sense deeper soil variable component. The mean ing water storage changes. In large moisture or groundwater. component of the gravity field is that part, this is due to a lack of reliable Researchers will soon have a new tool portion of the total gravity field information. Historically, it has proven to study subsurface water storage resulting from mass distributions that very difficult to develop networks for fluctuations in their arsenal. Their new remain virtually unchanged over gathering terrestrial water storage data. weapon comes from what might at first millions of years like the mass of the And even the data that do exist are not seem like an unlikely source. In March Earth or the locations of continents — really sufficient. Current ground-based of 2002, NASA launched GRACE — the phenomena that are more or less water storage measurement techniques first of the ESSP missions. Its five-year constant for purposes of computing the are labor intensive and provide only mission is to map the Earth’s gravity gravitational field. In contrast, the time point estimates of water storage. As a field with unprecedented accuracy variable component of the gravity field result, most of the world’s aquifer every 30 days. is that portion of the gravity signal systems are not surveyed regularly and caused by mass fluctuations that occur methodically, which renders assessing Gravity 101 on much shorter time scales including regional changes in groundwater levels changes in groundwater, ocean surface If Earth were a smooth sphere com- tedious or impossible. height, and atmospheric mass. Al- posed of similar elements or ingredi- though the mean gravity field is of Remote sensing has been touted as a ents, there would be no need for a considerable value in understanding possible solution to this problem. The GRACE mission. The assumption made the structure of the Earth and helping vantage point of space allows for in most introductory physics courses to reveal aspects of ocean circulation, it global- and synoptic-scale measure- that the acceleration due to Earth’s is the time variations in the gravity ments to be obtained, and makes it gravitational field has a constant value field, in particular those caused by more practical to track water storage would indeed be correct — end of water storage changes, that are of changes on a larger scale. The Ad- story. The reality, however, is that Earth interest in this study. vanced Microwave Scanning Radiom- is anything but smooth and uniform, eter for EOS (AMSR-E) onboard the and the gravity field is continually The workings of GRACE Aqua spacecraft, for example, has the changing, mostly due to variations in GRACE is different from most Earth capability to examine surface soil water content as it cycles between the observing satellite missions — Terra
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and Aqua for example — because it many scientific measurements related encouraging and indicated that doesn’t carry a suite of independent to climate change—hence, GRACE is GRACE should be able to detect scientific instruments on board. It does also a climate experiment as its name monthly water storage changes over not make measurements of the electro- implies. Accurate gravitational areas larger than 200,000 km2. Rodell magnetic spectrum like many of the measurements are a critical input to and Famiglietti are excited to see instruments currently flying in space. many scientific models used in GRACE data begin to flow this Instead, the two GRACE satellites oceanography, hydrology, geology, and summer, so that they can verify their themselves act in unison as the primary related disciplines and, for this reason, findings with actual data. instrument. Changes in the distance the Earth Science community is excited GRACE measurements by themselves, between the twin satellites are used to about potential applications for however, are not able to distinguish make an extremely precise gravita- GRACE data. One of the most intrigu- whether a change in gravity results tional field measurement. ing uses of data is expected to be using from a change in water mass, a change data from GRACE to track changes in in the mass of the overlying atmo- The two identical satellites orbit one water storage over terrestrial regions. behind the other in the same orbit sphere, or a change in the underlying plane at an approximate distance of 220 Matt Rodell at the Goddard Space solid Earth. Outside information is km (137 miles). As the pair circles the Flight Center and Jay Famiglietti at the needed to estimate the contribution of Earth, areas of slightly stronger gravity University of California at Irvine have the other components to the total (greater mass concentration) affect the done extensive work to prove this gravity measurement. To measure lead satellite first, pulling it away from concept, following up on work that had water storage changes using the the trailing satellite. The change in been done by John Wahr at the Univer- GRACE-technique, monthly average distance would certainly be impercep- sity of Colorado. Wahr demonstrated gravity fields are desired. Therefore, tible to our eyes, but an extremely the potential for using GRACE data to any gravity variations with a timescale precise microwave ranging system monitor water storage by deriving a of a month or less have to be removed onboard GRACE is able to detect these simulated GRACE gravity field and before the data is released for use, miniscule changes in the distance then separating out the water storage during the calculation of the original between the satellites. A highly component of the signal. Rodell and orbit and gravity solution. The GRACE accurate accelerometer, located at each Famiglietti’s work used 10 modeled science team uses a complex atmo- satellite mass center, measures the global time series of water storage to spheric model and an ocean model to non-gravitational accelerations (such as study water storage change for 20 river account for changes in gravity that those due to atmospheric drag) so that basins of varying size around the world arise from such phenomena as ocean only accelerations caused by gravity and determined how successful tides and the atmosphere-a technique are considered. Satellite GPS receivers GRACE will be in detecting the known as dealiasing. This can be determine the exact position of the variations. The findings indicate that thought of as "correcting" the raw satellite over the Earth to within a data from GRACE should be able to be gravity field for the effects of the daily centimeter or less. Scientists can take all used to decipher monthly water weather. this information, and use it to construct storage changes over continents for Now, the gravity measurement is ready 2 maps of the gravity field over the areas of approximately 200,000 km or for use in hydrological applications. Earth’s surface once every thirty days larger. They then conducted a study Any variations that remain have a during the planned five-year mission. over the state of Illinois. Illinois has an timescale of one month or larger (equal area of 145,800 km2 (below the mini- to or greater than the phenomena being Tracking water storage change over mum threshold for GRACE to detect observed) and can be dealt with by continents from space monthly water storage changes) but it scientists after they receive the data has the advantage of having a rather from the GRACE science team. Using GRACE data will do more than just extensive record of observed data. The various model simulations of the produce a more accurate gravitational results in Illinois had to be scaled up to atmosphere and the solid earth, the field plot, however. The measurements larger regions by assuming conditions effects not attributed to changes in from GRACE have important implica- in the surrounding area are similar to water storage can be removed and the tions for improving the accuracy of those in Illinois. Again, the results were "corrected" gravity field now represents
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only the portion that is attributed to the km2 and over shorter time scales. the size of the Mississippi River basin mass of water stored in a particular Atmospheric mass errors become (3,165,500 km2) will likely be able to region at a given time. This can then be dominant at larger scales, but aren’t have water storage change detected at converted to an equivalent water large enough to prevent the retrieval of monthly, seasonal, and annual time height. Two of these measurements meaningful water storage change intervals. As one might expect, the taken at different times can be used to measurements. method will be most effective when the study changes in water storage in a actual magnitude of the change being particular region. Limitations to the Technique observed is large. So, even in larger Sources of Error areas, the GRACE-technique will be Because it takes time for the GRACE most effective when there is a large But it’s not really as simple as subtract- satellites to fly over parts of the Earth, amount of variability in water storage ing the other components from the total the total magnitude of the water over the chosen time interval. In many gravity measurement. It would be as storage change at an instantaneous locations, changes between seasons simple as that if these models were time cannot be determined using this have the highest magnitude, and thus perfect representations of actual technique. Only the change in water seasonal water storage change may be conditions—but they aren’t. Each storage over a given region for a given easiest to detect using the GRACE- model used in this process is just a time interval is obtainable. So, as an technique. simulation of the actual conditions and example, one could use this technique thus less than perfect. There has to be to examine the change in water storage Honing in on groundwater some way to account for how much over the Mississippi River basin during these model imperfections impact the a chosen time interval, but one could When combined with still more outside final water storage measurement. So, not determine the height of the water information from other sources, the what the scientists have to do is devise table in the Mississippi River basin at GRACE-technique may be taken a step a way to look at how much error each the specific time the measurement was further and used to focus in on of the external models used in this obtained. In fact, in order to determine groundwater changes. This raises the calculation introduce to the final total water storage change over a region, very exciting possibility of allowing water storage estimate. A GRACE GRACE measurements from two changes in aquifer water storage to be water storage estimate could be distinct time periods must be used. tracked from space. Rodell and rendered useless if the total error Famiglietti have demonstrated this introduced by removing these other Rodell and Famiglietti’s two studies potential by examining data from the components is greater than the considered areas ranging in size from U.S. High Plains region. In order to magnitude of the actual water storage the state of Illinois up to entire river isolate the groundwater component of estimate. basins such as the Amazon and the total water storage change, the contri- Mississippi and looked at monthly, In addition to errors introduced by bution from all of the other compo- seasonal, and yearly time intervals for removing each of the other components nents to total water storage change all of these regions. They found that, of the total gravity measurement, the have to be determined and removed. generally speaking, the planned GRACE instrument itself introduces yet The main contributors to total water GRACE-technique will be more another source of error due to all of its storage change over continents are accurate for larger areas over longer various mechanical components. So to changes in soil moisture, snow water, time intervals. For example, an area the figure out the total error introduced to and reservoir storage (meaning, surface size of Illinois (145,800 km2) will the water storage estimate, one has to water that is restrained and well usually not be able to have month-to- account for the combined effects of the monitored). In the work they did in month water storage changes detected various model estimates and the Illinois, the two scientists found that using the GRACE-technique, but it is instrument itself. It turns out that, in the contributions to the total water more likely to have seasonal (three- general, the instrumental errors are the storage change resulting from reservoir month periods) changes detected, and primary impediment to using the storage (not including unregulated even more likely to have annual GRACE-technique to estimate water surface water flow as of yet) and snow changes detected. In contrast, an area storage in areas smaller than 200,000 water were usually insignificant
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relative to changes in soil moisture and accounted for when attempting to use models, the simulations produced will ground water. They make the assump- the GRACE-technique to isolate become more and more realistic and tion that the same is true of the High changes in groundwater from the total useful for predicting future conditions. Plains region. That leaves soil moisture water storage change. In actuality, over This will lead to forecasts with in- as the sole component that has to be an area the size of the High Plains, the creased accuracy and longer lead times, removed to get at elusive groundwater error in the soil moisture estimate turns so that by decade’s end water resource changes. It turns out that the U.S. High out to be the largest source of error— planners will have access to much more Plains, unlike most aquifers around the dominating atmospheric mass model detailed and dependable information world, has been well sampled and error and instrumental effects men- than they have at present. This will studied, meaning that lengthy time tioned above. However, the error does lead to improved ability to regulate series of soil moisture change exist. not appear large enough to render the water resources and make sure that This allows for soil moisture change GRACE-technique ineffective. sufficient quantity is present for the over time to be estimated fairly many needs of society—irrigation for accurately using models. The soil Conclusion agriculture, municipal supplies, and moisture contribution can be removed industry, just to name a few. It should From its satellite platform far above the and the remaining change in water also lead to rather substantial improve- Earth, GRACE will likely provide storage is that resulting from changes ments in our ability to predict, plan for, estimates of groundwater storage in groundwater. and respond to extreme events, such as changes all over the world. Preliminary floods and drought. Further refinements should allow for studies have shown that the GRACE- increasingly accurate estimates of technique will allow for estimates of groundwater storage using the annual groundwater change over the GRACE-technique. As time progresses, High Plains to within about 8.7 mm of soil moisture simulations will become their actual value. While there is some more and more realistic as data from question whether this represents a additional sources (such as AMSR-E major improvement for a densely and new surface observations) are monitored aquifer like the High Plains assimilated into the models. Future aquifer, as mentioned above, most efforts will also separate water stored aquifers around the world are not in the so-called intermediate zone nearly as well sampled as the High (between the lowest level of soil Plains aquifer. What’s more, even over moisture modeled and the top of the more extensively sampled areas, the water table), isolating the groundwater prospect of a technique that is less component even more accurately. labor intensive and does not require an Intermediate zone storage is still not extensive network of wells that is equal well understood and more work is to or perhaps slightly better than what needed to refine our understanding of is currently available is quite intrigu- this component of total water storage ing. GRACE may help to reveal so that it can be represented realisti- groundwater depletion in areas of the cally in models. Finally, the proposed world where it is not systematically follow-on mission to GRACE will documented or where it is not dis- replace the current microwave ranging closed for political reasons. Overall, the system with a laser interferometer, GRACE-technique seems to offer an greatly reducing instrumental errors, objective, unbiased method for and allowing viable measurements monitoring water storage changes on a over areas as small as 10,000 km2. global scale.
Using modeled soil moisture adds yet As this new information from GRACE another source of error that must be becomes assimilated into forecast
29 THE EARTH OBSERVER • May/June 2003 Vol. 15 No. 3
NASA’s Earth Science Enterprise Sponsors Creative Problem Solving Competition
— Charlotte Griner, [email protected], EOS Project Science Office — Steve Graham, [email protected], EOS Project Science Office
Over 13,000 students, coaches, parents, Division 1 3. Pennridge High School, Green and spectators gathered at the Univer- 1. Sharon Elementary School, Lane, Pennsylvania sity of Iowa in Ames, May 28-31 for the Team A, Charlotte, North Division 4 24th Annual Odyssey of the Mind World Carolina 1. Osrodek PsychoedukacjiI Finals, an international event where 2. McKinley School, Rydal, Damb, Gdansk, Poland teams come together to compete for the Pennsylvania 2 . Georgia Tech University, World Championship in their long- 3. Mantua Elementary School, Atlanta, Georgia term problem and division. Through a Team B, Fairfax, Virginia 3 . Lehigh University, grant, NASA’s Earth Science Enterprise Division 2 Bethlehem, Pennsylvania sponsored a problem titled “A Scene 1. Friendswood Junior High from Above,” one of the five long-term School, Friendswood, Texas The Odyssey of the Mind and NASA problems associated with this year’s 2. Churchville-Chili Interna- partnership is a natural collaboration. competitions. The students were tional School, Team A, Both organizations represent the best in challenged to design, build and run Spencerport, New York innovation, teamwork and creative three small vehicles to transport items 3. Shorecrest Preparatory School, problem solving. ESE hopes to inspire from an orbit area to an assembly Largo, Florida some of those students to become station in space. The vehicles were Division 3 future scientists and engineers. More added to a three-dimensional represen- 1. Myers Park High School, information on the Odyssey of the tation of a scene of the Earth as viewed Green Team, Charlotte, North Mind World Finals can be found at from space, and as the vehicles were Carolina www.odysseyofthemind.com/wf2003 added, the scene changed. The vehicles 2. Brien McMahon High School, were required to be powered in Norwalk, Connecticut different ways; one vehicle carrying its own energy source while the other two vehicles were powered by the momen- tum created by different sources.
During the 2002/03 school year millions of kids from across the world brainstormed, built, revised and perfected their solutions with the hopes of advancing from regional and state association tournaments to the World Finals. A total of 127 teams competed for the top awards in the NASA- sponsored problem. Following are the first, second and third place winners in each Division:
More than 13,000 students, coaches, parents, and spectators filled the Hilton Coliseum on Saturday evening, May 31 for the Odyssey of the Mind awards presentation and ceremonies.
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Earth Science Education Program Update
— Ming-Ying Wei, [email protected], NASA HQ — Theresa Schwerin, [email protected], IGES
New Investigator Program (NIP) information, please contact Dr. Ming- worldwide hands-on, primary and Proposals Due: August 15, 2003 Ying Wei, Manager, Education Pro- secondary school-based education and grams, Office of Earth Science, science program. It is a cooperative The New Investigator Program (NIP) in [email protected]. effort of schools, led in the U.S. by a Earth science was established in 1996 to Federal interagency program and encourage the integration of Earth NSF Program Announcement for supported by NASA, the National system science research and education EarthScope Proposals Science Foundation (NSF), the Environ- by scientists and engineers at the early mental Protection Agency (EPA), and stage of their professional careers. The Proposal Deadline: July 16, 2003 the U.S. State Department, in partner- program, designed for investigators in The National Science Foundation (NSF) ship with colleges and universities, Earth system science and applications has released a Program Announcement state, and local school systems, and at academic institutions and non-profit inviting proposals for EarthScope non-government organizations. organizations, emphasizes the early Science, Education and Related Internationally, GLOBE is a partnership development of professional careers of Activities. Full details are available at: between the United States and 102 these individuals as both researchers www.nsf.gov/pubs/2003/nsf03567/ other countries. For full position and educators. The program encour- nsf03567.htm. description, see www.fin.ucar.edu/hr/ ages scientists and engineers to careers/uco.cfm?do=jobDetailExt&job_ID= develop a broader sense of responsibil- The EarthScope facility (USArray, San 72. ity for effectively contributing to the Andreas Fault Observatory at Depth improvement of science education and [SAFOD]), and Plate Boundary U.S. Global Change Research Program the public science literacy; it provides Observatory (PBO) is a multi-purpose Website — New and Improved an opportunity for the investigators to array of instruments and observatories The U.S. Global Change Research develop partnerships and enhance their that will greatly expand the observa- Program has just updated its "New" skills, knowledge, and ability to tional capabilities of the Earth sciences page with a wide-ranging set of communicate the excitement, chal- and help advance understanding of the organized links to new online material. lenge, methods, and results of their structure, evolution, and dynamics of The page is usually updated monthly work to teachers, students, and the the North American continent. The and provides an easy way to monitor public. Of particular interest is the EarthScope observational facility important scientific developments investigators' ability to promote and provides a framework for broad, without having to dig around dozens increase the use of Earth remote integrated studies across the Earth of different web sites. See the additions sensing through the proposed research sciences. at www.usgcrp.gov/usgcrp/new.htm. and education projects. Director, The GLOBE Program NIP proposals are openly solicited DLESE K-12 Earth Science Listserves approximately every 18 months. The The University Corporation for awards range between $80,000-$120,000 Atmospheric Research (UCAR) has an This web site provides information per year for a period of up to three opening for the position of Director, about Earth science/Geoscience years, For more information, see Global Learning and Observations to education listservs in the United States. research.hq.nasa.gov under "Office of Benefit the Environment (GLOBE) See dlesecommunity.carleton.edu/k12/ Earth Science (Code Y)." For more Program. The GLOBE Program is a listservs.
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National Public Radio’s, “All Things Considered” - Joel Levine (NASA Langley) discusses the environmental impact of the burning Iraqi oil wells.
— Robert Gutro, [email protected], NASA Earth Science News Team
NASA’s Aqua Satellite Marks One NASA Research Helps Highlight Year, May 29, Spacedaily.com - Claire Lightning Safety Awareness Week, Parkinson, Aqua Project Scientist June 19, Aboutweather, Der Wissenschaft (NASA/GSFC) was quoted in this (Germany) - Steven Goodman, Dennis article on Aqua’s first year. Aqua Boccippio, Richard Blakeslee, Hugh provided views of fires, snowstorms, Christian, and William Koshak (all typhoons, a volcanic eruption and dust from NASA/Marshall) helped create a storms. high-resolution world map showing the frequency of lightning strikes. QuakeSim, May 27, KTVU-TV, CH 2 Oakland; May 22, KNBC-TV, Los Angeles, NASA Rainfall Measurement, June 15; CA — Walt Brooks and Creon Levit The Huntsville Times, (Ala.) - Gary (NASA Ames) were interviewed about Jedlovec (NASA MSFC) discusses the how JPL ‘QuakeSim’ program software Cooperative Huntsville Area Rainfall will run on the biggest parallel Measurements (CHARM), a local supercomputer of its kind in the world precipitation-measurement network. at NASA Ames.
Study Suggests Ancient Oceans Had Students at Ames, May 24 and 25, Low Levels of Oxygen, June 10, KCBS-AM, San Francisco - Jay Skiles Associated Press, quotes David Des (NASA/Ames) was interviewed about Marais (NASA/Ames) who is co- students who will study Earth Science author of a study included in the June 5 at Ames this summer. issue of the journal Nature.
Precipitation in the Southern U.S., Spotlight on Ames Researcher, June 3, May 20; WHNT-TV Channel 19, Chicago Tribune, column about NASA Huntsville Ala. - John Christy, Gary researcher Azadeh Tabazadeh (NASA/ Jedlovec and Bob Oglesby (NASA Ames) MSFC) discuss precipitation and drought in the Southern United States. Jet Writers in the Sky, June 2, Knoxville News Sentinel, knoxnews.com - Pat Potential Pollution Dangers of the Air Minnis (NASA Langley) speaks about In Baghdad Due to Burning Oil, Thick the contrail studies conducted during Smoke and Sandstorms, March 27, the 2001 air traffic shutdown.
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February 24-27, 2004 EOS Science Calendar Global Change Calendar 8th Specialist Meeting on Microwave Radiometry and Remote Sensing July 21 - 22, 2003 Robert.F.Cahalan@nasa. gov. Applications, Rome, Italy. URL: www.microrad04.org SEDAC User Working Group meeting, New 2003 York, NY. Contact: Robert Chen, July 21 - 25 [email protected]. IGARSS 2003, Toulouse, France. Email: [email protected], URL: www.igarss03.com. July 28 - August 1
“Earth Science for Safety” — 11th meeting August 30 - September 6 of the ESIP Federation, Boulder, Colorado. Second International Swiss NCCR Climate URL: www.esipfed.org, Contact: Dave Summer School: “Climate Change — Jones, [email protected] Impacts of Terrestrial Ecosystems.” Grindelwald, Switzerland. Contact: Kaspar September 23 - 25 Meuli, Email: [email protected], URL: www.nccr-climate.unibe.ch. HDF & HDF-EOS Workshop VII , Silver Spring, MD. Call for abstracts. Contact: Richard Ullman, Richard.E.Ullman@ September 8 - 10 nasa.gov. URL: hdfeos.gsfc.nasa.gov Sixth Baiona Workshop on Signal Processing in Communications, Baiona, Spain. Contact Carlos Mosquera, Email: September 23 - 25 [email protected], URL: CERES Science Team Meeting, Hampton, www.baionaworkshop.org Va. Contact: Gary Gibson, Gary.G.Gibson @nasa.gov. September 23 - 26 Oceans ‘03, San Diego, CA. Contact: Brock September 30 Rosenthal, Email: [email protected], Aura Science Team Meeting, Pasadena, CA. Tel: (858) 454 4044, URL: www.o- Contact: Anne Douglass, Anne.R. vations.com. [email protected]. November 10 - 14 October 15 30th International Symposium on Remote Sensing of Environment, Honolulu, HI. SEDAC User Working Group meeting, Email: [email protected], URL: Montreal, Canada. Contact: Robert Chen, www.symposia.org. [email protected].
December 4-6 December 9-12
SORCE Science Team Meeting, Sonoma, American Geophysical Union (AGU) San CA. Contact: Bob Cahalan, Francisco. E-mail: [email protected] URL: www.agu.org/meetings/fm03/ 2004
January 11-15
American Meteorological Society Annual Meeting, Seattle, Wa. URL: www.ametsoc.org.
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