EARTH OBSERVING SYSTEM

Earth Science Enterprise

To Understand and Protect Our Home Planet NASA EARTH SCIENCE ENTERPRISE

COLIN SEFTOR (RAYTHEON) AND CHRISTINA HSU (UMBC)

Earth Observing System Aura

Goddard Space Flight Center Greenbelt, Maryland 20771 NP-2004-4-626-GSFC

PHOTOS OF EARTH’S ATMOSPHERE COURTESY OF EARTH SCIENCES AND IMAGE ANALYSIS LABORATORY, NASA JOHNSON SPACE CENTER. AURA SATELLITE IMAGE BY JESSE ALLEN (SSAI) A Mission Dedicated to the Health of the Earth’s Atmosphere AURA INSTRUMENTS A Mission Dedicated to the Health of the Earth’s Atmosphere HIRDLS: USA, United Kingdom High Resolution Dynamics Limb Sounder

Stratospheric and upper tropospheric trace gases and aerosols measured by infrared limb emission

MLS: USA How is the Microwave Limb Sounder Earth changing Stratospheric and upper tropospheric trace gases measured by microwave limb emission and what Earth’s atmosphere provides sustenance to all living things are the OMI: Netherlands, Finland and protects life from the harsh space environment consequences for life on Ozone Monitoring Instrument The Earth’s Ozone Shield protects The Earth’s Climate is affected by Earth? Tropospheric and stratospheric ozone, aerosols, air quality and surface ultraviolet radiation measured by backscatter all life changes in atmospheric composition The Aura mission ultraviolet and visible radiation Stratospheric ozone has decreased 3% globally between It is undeniable that human activity is beginning to alter will explore the TES: USA 1980 and 2000 and thins by 50% over Antarctica in winter the climate. The global rise in surface temperatures since atmosphere’s and spring. Depletion of the ozone layer allows more the 1950’s is correlated with the increase in greenhouse natural variability Tropospheric Emission Spectrometer ultraviolet radiation to reach the surface. Increases in gases. Changes in carbon dioxide, methane, nitrous oxide, ultraviolet radiation are known to have harmful effects ozone, cloud cover, water vapor and aerosols all contribute and its response Tropospheric and lower stratospheric trace gases and aerosols to human activity on living things. The Montreal Protocol and its amend- to climate change. measured by nadir and limb infrared emission ments have banned the use of ozone destroying chemicals

so that we OF HIRDLS,PHOTOS MLS, OMI, BY INSTRUMENT TEAMS. AND TES INSTRUMENTS can better predict and the rate of ozone depletion seems to have slowed. changes in the Electromagnetic Spectrum Climate change will have an impact on how quickly Aura is designed to answer questions ozone recovers. Earth system. about changes in our life-sustaining atmosphere HIRDLS MLS MLS The Earth’s Air Quality is fundamental Aura’s four instruments will study the atmosphere’s to public health and ecosystems chemistry and dynamics. Aura’s measurements will enable us to investigate questions about ozone trends, air quality OMI TES The atmosphere has no political boundaries; air pollution changes and their linkage to climate change. moves great distances across oceans and continents. The UltravioletVisible InfraredSubmillimeter Microwave quality of air has degraded over certain parts of the world Aura’s measurements will provide accurate data for pre- −7 −6 −5 −4 −3 −2 and has become a health issue. Severe air pollution dictive models and provide useful information for local and 10 10 10 10 10 10 episodes increase mortality. national agency decision support systems. Wavelength (meters) Aura is the third in a series of large Earth observing plat- The various gases in the atmosphere absorb or emit radiation at specific wavelengths depending forms to be flown by the National Aeronautics and Space on their molecular structure. Aura’s instruments will measure atmospheric constituents by Administration (NASA) with international contributions. observing the Earth over a large range in the electromagnetic spectrum. Measurements will be Aura along with EOS Terra (launched December, 1999) and made of solar backscatter radiation in the ultraviolet and visible regions and of thermal Aqua (launched May, 2002) will provide an unprecedented emission in the infrared and microwave regions.

VISUALIZATION OF EARTH HORIZON BY JESSE ALLEN (SSAI) VISUALIZATION view of the global Earth system. SCIENCE QUESTIONS

Is the stratospheric ozone layer recovering? Polar Stratospheric Clouds

Ozone Facts he stratospheric ozone layer shields life ozone molecule combines with an oxygen atom Sources, Reservoirs on Earth from harmful solar ultraviolet to form two oxygen molecules, or through and Radicals T (UV) radiation (wavelengths shorter than catalytic cycles involving hydrogen, nitrogen, n In the present day 340 nm). Research has clearly shown that chlorine or bromine containing species. The Source gases – These gases stratosphere, the natu- excess exposure to UV radiation is harmful to atmosphere maintains a natural balance ral balance of ozone are nearly inert in the lower agriculture and causes skin cancer and eye between ozone formation and destruction. atmosphere, but they are chemistry has been problems. Excess UV radiation may suppress sources of ozone-destroying altered by man-made the human immune system. The natural balance of chemicals in the strato- radicals when broken apart chemicals, such as sphere has changed, particularly due to the by ultraviolet radiation, reactions with the hydroxyl chlorofluorocarbons Ozone is formed naturally in the stratosphere presence of man-made chlorofluorocarbons through break-up of oxygen molecules (O ) by (CFCs). CFCs are non-reactive and accumulate radical (OH), or reactions (CFCs). 2 with excited atomic oxygen solar UV radiation. Individual oxygen atoms in the atmosphere. They are destroyed in the (O1D). CFCs are sources of n Recent data show that can combine with O molecules to form ozone high stratosphere where they are no longer 2 chlorine radicals and N2O ozone is being depleted molecules (O3). Ozone is destroyed when an shielded from UV radiation by the ozone layer. is the source of nitrogen at a slower rate than a radicals. decade ago, but it is MARK SCHOEBERL (NASA GFSC) Stratospheric Chemical Processes Thin clouds made of ice, nitric acid, and sulfuric acid mixtures form in the polar stratosphere when tem- Reservoirs – These gases too soon to tell if this peratures drop below -88 C (-126 F). In such polar stratospheric clouds (PSCs) active forms of chlorine are less inert than source trend is a result of the are released from their reservoirs. This particular PSC appeared over Iceland at an altitude of 22 km on gases but do not destroy February 4, 2003. Its beautiful colors result from refraction of sunlight by its very small ice crystals. ozone themselves. Reservoir international protocols gases are formed when radi- restricting CFC produc- cals react with source gases, tion. for example, chlorine atoms Destruction of CFCs yields atomic chlorine, an Ozone Warms the Stratosphere (Cl) react with methane mol- n Aura’s instruments will efficient catalyst for ozone destruction. Other ecules (CH4) to produce the measure the total man-made gases such as nitrous oxide (N2O) reservoir hydrochloric acid and bromine compounds are broken down in From the surface, temperatures decrease with (HCl). Reservoirs are also ozone column, ozone altitude. Then, in the stratosphere, tempera- the stratosphere and also participate in ozone formed when radicals react profiles and gases tures begin to rise, because ozone absorbs destruction. with each other, for example, important in ozone solar UV energy, heating the stratosphere. OH reacts with nitrogen Above 50 km ozone heating falls off and the dioxide (NO2) to produce chemistry. Satellite observations of the ozone layer began temperatures decrease again. Above 80 km nitric acid (HNO3). in the 1970s when the possibility of ozone very high energy solar radiation begins to heat depletion was just becoming an environmental the atmosphere again. Radicals – These are the concern. NASA’s Total Ozone Mapping ozone destroying gases Spectrometer (TOMS) and Stratospheric such as chlorine monoxide (ClO) and nitric oxide (NO). Aerosol and Gas Experiment (SAGE) have Radicals are freed from their provided long-term records of ozone. In 1985 reservoir gases by photolysis BARBARA SUMMEY (SSAI) the British Antarctic Survey reported an unex- and by chemical reactions The stratospheric ozone layer shields us from cumulus clouds. These compounds are broken pectedly deep ozone depletion over Antarctica. involving reservoir gases and solar ultraviolet radiation. Chemicals that destroy down by the ultraviolet radiation in the strato- other radicals. ozone are formed by industrial and natural sphere. Byproducts of the breakdown of these The annual occurrence of this depletion, popu- larly known as the ozone hole, alarmed scien- processes. With the exception of volcanic injec- chemicals are radicals such as NO2 and ClO that tion and aircraft exhaust, these chemicals arrive catalyze ozone destruction. Aerosols and clouds tists. Specially equipped high-altitude NASA in the stratosphere through the tropical upwelling can accelerate ozone loss through reactions on aircraft established that the ozone hole was region. Methane (CH4), chlorofluorocarbons cloud surfaces. Thus volcanic clouds and polar due to man-made chlorine. TOMS and SAGE (CFCs), nitrous oxide (N2O) and water are injected stratospheric clouds can indirectly contribute to data also showed smaller but significant ozone into the stratosphere through towering tropical ozone loss. continues on page 4

2 AURA 3 AURA When we try to SCIENCE QUESTIONS pick out anything by itself, we find it is tied to losses outside the Antarctic region. In 1987 peratures fall below –88 C. Polar stratospheric apart, are leveling off as well (See Global HCl Winter Polar Ozone in the Northern/Southern Hemisphere an international agreement known as the clouds (PSCs) form at these low temperatures. figure). Recent studies have shown that the everything else Montreal Protocol restricted CFC production. The reservoir gases HCl and ClONO2 react on rate of ozone depletion is also decreasing. in the universe. In 1992, the Copenhagen amendments to the the surfaces of cloud particles and release chlorine. Montreal Protocol set a schedule to eliminate Recovery of the ozone layer may not be as sim- all production of CFCs. Ground-based data have shown that CFC ple as eliminating the manufacture of CFCs. John Muir amounts in the troposphere are leveling off, Climate change will alter ozone recovery (1838-1914) Severe ozone depletion occurs in winter and while data from the Halogen Occultation because greenhouse gas increases will cause U. S. naturalist, spring over both polar regions. The polar strat- Experiment (HALOE) on the Upper the stratosphere to cool. This cooling may explorer osphere becomes very cold in winter because of Atmosphere Research Satellite (UARS) have temporarily slow the recovery of the ozone the absence of sunlight and because strong shown that amounts of HCl, a chlorine reser- layer in the polar regions, but will accelerate winds isolate the polar air. Stratospheric tem- voir that is produced when CFCs are broken ozone recovery at low and middle latitudes.

What will Aura do? TOMS Global Ozone Compared with Model Northern Hemisphere Southern Hemisphere Aura’s instruments will observe the important At both polar regions, climate and chem- The Antarctic ozone hole of 2003 STUDIO) GREG SHIRA (NASA GSFC SCIENTIFIC VISUALIZATION sources, radicals, and reservoir gases active in istry combine to deplete ozone during (above, right) was the second largest Comparing models with observations allows spring months. Dark blue indicates low- ever observed. The dark blue indicates 310 us to check how accurately we can predict ozone chemistry. Aura data will improve our Nimbus 7 TOMS Eruption of Pinatubo 65N - 65S est ozone amounts. Arctic total ozone the region of maximum ozone depletion. stratospheric ozone trends. In the image to capability to predict ozone change. Aura data amounts seen by TOMS in March 2003 TOMS images (below) illustrate the the left, TOMS global ozone measurements will also help untangle the roles of transport (above, left) were among the lowest ever development of the ozone hole during 300 (Nimbus 7, Meteor 3, Earth Probe) show and chemistry in determining ozone trends. observed in the northern hemisphere. the 1980’s and 1990’s. Earth Probe TOMS that ozone has a strong annual cycle, and Recovery predicted by model decreases following a major volcanic erup- 290 tion. Global ozone has decreased overall by

OZONE (DU) about 3% since 1980. A model that calcu- lates annual mean ozone amounts com- 280 pares favorably with TOMS observations Meteor 3 TOMS and predicts ozone layer recovery after 2020. The model total ozone varies slowly 1980 1990 2000 2010 2020 due to the 11-year solar cycle. Aura’s OMI YEAR will continue the TOMS total ozone record. CHARLES JACKMAN AND RICHARD MCPETERS (BOTH NASA GSFC) CHARLES JACKMAN BARBARA SUMMEY (SSAI) Global HCl

UARS HALOE measurements of stratospheric chlorine (HCl) 3.7 The Upper Atmosphere at 55km show that internation- Research Satellite HALOE HCl al controls on CFCs are work- ing. HCl amounts have leveled 3.4 The first comprehensive satellite measurements off and are now decreasing. of stratospheric gases, solar particle and radia- tion fluxes and upper atmosphere winds were Aura’s MLS will continue the 3.1 HALOE HCl record. made by NASA’s Upper Atmosphere Research Satellite (UARS). UARS was deployed in 1991 HCl (ppbv) from the Space Shuttle Discovery and continues 2.8 to gather data from five of its 10 instruments. UARS was designed to study the chemistry and 2.5 dynamics of the middle and upper stratosphere 19901995 2000 2005 while Aura is designed to study the lower strato- YEAR sphere and upper troposphere. Aura will continue JAMES M. RUSSELL III (HAMPTON UNIVERSITY) many of the measurements pioneered by UARS. umpgal.gsfc.nasa.gov/uars-science.html JESSE ALLEN (SSAI)

4 AURA AURA 5 SCIENCE QUESTIONS

What are the processes controlling air quality? The Sources of Tropospheric Ozone

Air Quality Facts griculture and industrial activity have The U.S. Environmental Protection Agency grown dramatically along with the (EPA) has identified six criteria pollutants: A human population. Consequently, in carbon monoxide, nitrogen dioxide, sulfur Air quality is a continu- n parts of the world increased emissions of pollu- dioxide, ozone, lead, and particulates (aerosols). ing environmental con- tants have significantly degraded air quality. Of these six pollutants, ozone has proved cern because poor air Respiratory problems and even premature the most difficult to control. Ozone chemistry quality impacts human death due to air pollution occur in urban and is complex making it difficult to quantify health and agricultural some rural areas of both the industrialized and the contributions to poor local air quality. productivity. developing countries. Wide-spread burning for Pollutant emission inventories needed for pre- agricultural purposes (biomass burning) and dicting air quality are uncertain by as much as n Ozone precursors are forest fires also contribute to poor air quality, 50 percent. Also uncertain is the amount of pollutant gases such as particularly in the tropics. The list of culprits ozone that enters the troposphere from the carbon monoxide (CO), in the degradation of air quality includes tro- stratosphere. nitrogen dioxide (NO2), pospheric ozone, a toxic gas, and the chemicals methane (CH4) and that form ozone. These ozone precursors are For local governments struggling to meet other hydrocarbons that nitrogen oxides, carbon monoxide, methane, national air quality standards, knowing more BARBARA SUMMEY (SSAI) react in the troposphere and other hydrocarbons. Human activities such about the sources and transport of air pollu- Tropospheric ozone comes from several sources. industrial processes, biomass burning, automobile to produce ozone. as biomass burning, inefficient coal combus- tants has become an important issue. Most pol- Biomass burning and industrial activity produce CO exhaust and lightning also form tropospheric and volatile organic compounds (VOCs) which are ozone. A small amount of tropospheric ozone also Sulphur Dioxide (SO ) is tion, other industrial activities, and vehicular lution sources are local but satellite observa- 2 traffic all produce ozone precursors. tions show that winds can carry pollutants for oxidized to form ozone. Nitrogen oxides (NOx) from comes from the stratospheric ozone layer. a precursor for sulfate great distances, for example from the western aerosol. and mid-western states to SCIAMACHY Measurement n Worldwide emissions of the east coast of the United nitrogen dioxide, carbon States, and sometimes even Forecasting Severe Pollution Events from one continent to anoth- monoxide, volatile hydro- er. Observations and models carbons and aerosols NASA is working with the Environmental rough estimates of ozone and aerosols. Aura will show that pollutants from have increased consider- Protection Agency and the National Oceano- provide more detailed maps of pollutants such as graphic and Atmospheric Administration to exam- ozone and NO2 that can be combined with weath- Southeast Asia contribute to ably, but there is still ine how models will be used to forecast pollution er forecast models. These two images from the poor air quality in India. uncertainty in the emis- events. Models use satellite data to begin a fore- EPA AirNow website illustrate what these models Pollutants crossing from sion rates and distinc- cast. Satellites launched before Aura provide will be able to do. The images show that the area China to Japan reach the tions between anthro- of unhealthy surface west coast of the United ozone (red) moves from States. Pollutants originat- pogenic and natural Tennessee (left panel) sources of these emis- to eastern Pennsylvania ing in the United States can sions. and New Jersey (right reduce air quality in Europe. panel) in the course of Precursor gases for as much n Aura measures and three days. In addition as ten percent of ozone in maps five of the EPA’s to forecasting, satellite surface air in the United

data and models can ANDREAS RICHTER (UNIVERSITY OF BREMEN) six “criteria pollutants,” States may originate outside discriminate between the country. We have yet to SCIAMACHY is a German, Dutch and Belgian instrument on the helping to improve emis- locally produced European Space Agency Envisat satellite. SCIAMACHY is able to esti- pollution and pollution quantify the extent of inter- sions inventories and to mate the monthly average of tropospheric NO2 amounts over the United that is brought by regional and inter-continen- States. High levels of NO correspond to urban locations and special distinguish between AUG 9 AUG 12 2 transport. tal pollution transport. anthropogenic and natu- emission sites like power plants. OMI will make similar measurements U.S. ENVIRONMENTAL PROTECTION AGENCY (EPA) AND NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION (NOAA) with higher horizontal resolution and daily global coverage. ral sources. continues on page 8

6 AURA AURA 7 SCIENCE QUESTIONS Two Satellite Views of Pollution Transport

The strongest Long Range Pollution Transport above the surface layers. OMI will make simi- lar measurements with better spatial resolution arguments prove The atmosphere can transport pollutants long and will provide new information about distances from their source. Satellite measure- aerosol characteristics. nothing so long ments by EOS Terra’s MOPITT instrument as the conclusions have shown carbon monoxide streams extend- What will Aura do? ing almost 18,000 km from their source (this are not verified page). TOMS has tracked dust and smoke The Aura instruments are designed to study events from Northern China to the east coast tropospheric chemistry; together Aura’s instru- by experience. of the United States (see back cover). ments provide global monitoring of air pollu- Experimental science tion on a daily basis. They measure five of the On July 7, 2002, MODIS on EOS-Terra and six EPA criteria pollutants (all except lead). is the queen of TOMS captured smoke from Canadian forest Aura will provide data of suitable accuracy to sciences and the goal fires as the winds transported it southward (see improve industrial emission inventories, and page 9). This pollution event was responsible also to help distinguish between industrial and of all speculation. for elevated surface ozone levels along the east natural sources. Because of Aura, we will be coast. TOMS has high sensitivity to aerosols able to improve air quality forecast models. Roger Bacon like smoke and dust when they are elevated ORAM KAUFMAN (NASA GSFC) 13th Century English Y philosopher, scientist Carbon Monoxide ORAM KAUFMAN (NASA GSFC) Y

-150 -120 -90 -60 -30 030 60 90 120 150 MODIS July 7 ortho-rectified image shows smoke streaming southward from forest fires (red) in Canada. 60 60 30 30 60 30 30 60 0 0 -30 -30 0 -30 -30 0 -60 -60 -60 -60

-150 -120 -90 -60 -30 030 60 90 120 150 -150 -120 -90 -60 -30 030 60 90 120 150 ORAM KAUFMAN (NASA GSFC) Y 30 70 110 150 190 230 Upper image shows raw RGB MODIS view of July 7, 2002 CO (ppbv ) MOPITT TEAM smoke event. Lower image shows aerosol large mode particle South America and Africa produce plumes which fraction estimated using other MODIS data. Particles coagu- Biomass burning and urban pollution plumes can propagate into the South Atlantic. The African late with time, so the largest particles are seen farthest from be followed using measurements of CO from plume also propagates into the Indian Ocean. the fire. MOPITT on EOS Terra. Agricultural burning in Biomass. Burning in Southeast Asia produces a plume that extends across the Pacific. HERMAN (NASA GSFC) JAY TOMS July 7 image shows smoke streaming southward from forest fires in Canada.

8 AURA AURA 9 SCIENCE QUESTIONS

UARS MLS Upper Tropospheric Water Vapor and El Niño How is Earth’s climate changing?

Climate Change arbon dioxide and other gases trap Aerosols are an important but uncertain agent Increasing carbon dioxide also affects the cli- infrared radiation that would otherwise of climate change. Aerosols alter atmospheric mate of the upper atmosphere. Where the Facts Cescape to space. This phenomenon, the temperatures by absorbing and scattering atmosphere is thin, increasing CO2 emits greenhouse effect, makes the Earth habitable. radiation. Aerosols can either warm or cool more radiation to space, thus cooling the Sept 1996 normal year n Like carbon dioxide, Increased atmospheric emissions from industri- the troposphere. Therefore, aerosols also mod- environment. Observations show that over ozone, aerosols, and al and agricultural activities are causing cli- ify clouds and affect precipitation. Sulfate recent decades, the mid to upper stratosphere water vapor contribute mate change. Industry and agriculture produce aerosols can reduce cloud droplet size, making has cooled by 1 to 6 C (2 to 11 F) primarily to climate change. trace gases that trap infrared radiation. The clouds brighter so that they reflect more solar due to increases in CO2. This cooling will concentrations of many of these gases have energy. Black carbon aerosols strongly absorb produce circulation changes in the strato- n Gases such as carbon increased and thus have added to the green- solar radiation, warming the mid-troposphere sphere that will change how trace gases are dioxide (CO2), water house effect. Since the turn of the century, the and reducing cloud formation. Poor know- transported.

vapor (H2O) and ozone global mean lower tropospheric temperature ledge of the global distribution of aerosols WILLIAM READ (NASA JPL) heat the troposphere by has increased by more than 0.4 C. This contributes to a large uncertainty in climate Water vapor is the most important green- Sept 1997 developing El Niño Year trapping infrared radia- increase has been greater than during any other prediction. house gas. Some measurements suggest that century in the last 1000 years. water vapor is increasing in the stratosphere. -50-25 0 +25 +50 tion that would other- deviation (ppmv) Ozone absorbs solar radiation, warming the This increase may be due to changes in the wise escape to space. Water vapor measurements from MLS on UARS show the contrast Ozone plays multiple roles in climate change, stratosphere. Man-made chlorofluorocarbons transport of air between the troposphere and Trapping infrared radia- between 1996 (a “normal” year) and 1997 (an “El Niño” year). In because it absorbs both ultraviolet radiation from have caused ozone depletion, leading to lower the stratosphere caused by climate change, or tion is called “the 1996 the most convection and the highest mixing ratios for tropical the sun and infrared radiation from the Earth’s temperatures. Low temperatures, in turn, lead it could be due to changes in the microphysi- upper tropospheric water vapor (red) occur over Indonesia; the lowest greenhouse effect” and surface. Tropospheric ozone is as important as to more persistent polar stratospheric clouds cal processes within tropical clouds. More mixing ratios for tropical upper tropospheric water vapor (blue) occur the gases that absorb methane as a greenhouse gas contributor to cli- and cause further ozone depletion in polar measurements of upper tropospheric water in the eastern Pacific. In 1997 the sea surface temperatures in the this radiation are called mate change. An accurate measurement of the regions. vapor, trace gases and particles are needed to tropical eastern Pacific are much warmer than in 1996, and the distribution of tropospheric ozone will improve untangle the cause and effect relationships of region of intense convection shifts eastward away from Indonesia. “greenhouse gases.” The situation is reversed in 1997 from 1996 with the highest mixing climate modeling and climate predictions. these various agents of climate change. We Improved knowledge of ratios for upper tropospheric water vapor in the eastern Pacific, and n can verify climate models of the atmosphere very low mixing ratios over Indonesia. the sources, sinks and Global Climate Change only with global observations of the atmos- the distribution of phere and its changes over time. Earth Probe TOMS Aerosol Index greenhouse gases are The chart at right distin- guishes among various What will Aura Do? needed for accurate pre- human and natural agents dictions of climate of global climate change Aura will measure greenhouse gases such as change. between 1750 and 2000. methane, water vapor, and ozone in the upper Greenhouse gases have been the most influential troposphere and lower stratosphere. Aura also n Aura’s measurements of agents of warming, and sul- will measure both absorbing and reflecting ozone, water vapor and phate aerosols have been aerosols in the lower stratosphere and lower aerosols in the tropo- the most influential agents troposphere, water vapor measurements inside sphere and lower strato- of cooling. Aura measure- the high tropical clouds, and high vertical res- sphere will improve ments will help climate mod- olution measurements of some greenhouse els by measuring stratos-

climate prediction. pheric and tropospheric gases in a broad swath (down to the clouds) HERMAN (NASA GSFC) JAY ozone and aerosol amounts. across the tropical upwelling region. All of Aerosols affect climate both directly by reflecting and absorbing sun- Aura measurements will these measurements contribute key data for light and indirectly by modifying clouds. The TOMS aerosol index is an also help untangle climate climate modeling and prediction. indicator of smoke and dust absorption. The image shows aerosols feedbacks by measuring crossing the Atlantic and Pacific oceans. Dust from the Sahara upper tropospheric water

JAMES HANSEN (NASA GISS) desert is carried westward toward the Americas. Asian dust and vapor and cirrus clouds. pollution travel to the Pacific Northwest.

10 AURA AURA 11 AURA INSTRUMENTS

High Resolution Dynamics Limb Sounder Simulated HIRDLS Sampling HIRDLS

HIRDLS INSTRUMENT TEAM

HIRDLS Instrument IRDLS is an infrared limb-scanning HIRDLS Contributions to HIRDLS Contributions to radiometer measuring trace gases, Characteristics Understanding Stratospheric Ozone Understanding Air Quality Htemperature, and aerosols in the upper troposphere, stratosphere, and mesosphere. The largest ozone depletions occur in the polar HIRDLS will measure ozone, nitric acid, and n HIRDLS is an advanced, The instrument will provide critical informa- winter lower stratosphere. HIRDLS will water vapor in the upper troposphere and scanning 21-channel tion on atmospheric chemistry and climate. retrieve high vertical resolution daytime and lower stratosphere. With these measurements, infrared radiometer Using vertical and horizontal limb scanning nighttime ozone profiles in this region. scientists will be able to estimate the amount observing the 6-17 technology HIRDLS will provide accurate of stratospheric air that descends into the micron thermal emis- measurements with daily global coverage at HIRDLS will measure NO2, HNO3 and troposphere and will allow us to separate natu- CFCs, gases that play a role in stratospheric ral ozone pollution from man-made sources. sion of the Earth’s high vertical and horizontal resolution. The ozone depletion. Although international limb. University of Colorado, the National Center for Atmospheric Research (NCAR), Oxford agreements have banned their production, HIRDLS Contributions to 0N2O (ppbv) 450 CFCs are long-lived and will remain in the n Infrared instruments, University (UK) and Rutherford Appleton Understanding Climate Change LESLIE LAIT (SSAI) Laboratory (UK) designed the HIRDLS instru- stratosphere for several more decades. By without HIRDLS hori- HIRDLS will measure water vapor and ozone, The need for high horizontal resolution measurements ment. Lockheed Martin built and integrated measuring profiles of the long-lived gases at zontal scanning capa- both important greenhouse gases. The instru- of the stratosphere is illustrated above. Using a model, the instrument subsystems. The National 1.2 km vertical resolution, from the upper tro- bility, have flown on ment is also able to distinguish between aerosol the long-lived trace gas N2O is transported by observed Environmental Research Council funded the posphere into the stratosphere, HIRDLS will winds. The transport processes produce filamentary previous NASA atmos- types that absorb or reflect incoming solar radia- United Kingdom participation. make it possible to quantify the transport of structures that are predicted but have never been pheric research satel- air from the troposphere into the stratosphere. tion. HIRDLS will be able to map high thin observed globally. HIRDLS high horizontal resolution cirrus clouds that reflect solar radiation. lites such as Nimbus 7 HIRDLS makes key contributions to each of measurements will be able to observe these structures which are signatures of transport. and UARS. Aura’s three science questions. A summary of HIRDLS data products appears on page 29. n HIRDLS looks backward and scans both verti- Simulated HIRDLS Ozone Measurements Ozone Profile cally and horizontally IRDLS Co- across the satellite HPrincipal HIRDLS spatial track. Very precise Investigators Dr. coverage has John Gille (left), and gyroscopes provide been simulated Dr. John Barnett instrument pointing using an atmos- (right) hold a model information. To detect pheric chemistry of the Aura space- model. The the weak infrared radia- craft. Gille and HIRDLS instru- Barnett have led tion from the Earth’s ment team “flew” the development limb, HIRDLS detectors the spacecraft and application of have to be kept at tem- through the IR limb sounding. model to test the Gille and Barnett peratures below liquid retrieval algorithm JOHN GILLE (NCAR) and their team are responsible for the instrument calibration, develop- nitrogen. An advanced and demonstrate HIRDLS high vertical resolution measurements ment of the algorithms, monitoring instrument performance and data cryogenic refrigerator the ability of have been demonstrated using model data. processing. Dr. Gille is a senior researcher at the National Center for HIRDLS to map The solid line is the “true” profile taken from will keep the detectors Atmospheric Research and a professor at the University of Colorado. trace ozone. a model. The radiance that HIRDLS would Dr. Barnett is a Lecturer in atmospheric physics at Oxford University. cool. Colors represent observe is computed from this profile. The red ozone abundance horizontal lines show the ozone mixing ratio at 16 km altitude. measurement and error retrieved with the

HIRDLS SCIENCE TEAM HIRDLS algorithm.

12 AURA AURA 13 AURA INSTRUMENTS

Microwave Limb Sounder MLS

MLS INSTRUMENT TEAM

MLS Instrument LS is a limb scanning emission MLS Contributions to MLS Measurements of Water Vapor Characteristics microwave radiometer. MLS measures Understanding Stratospheric Ozone radiation in the GHz and THz fre- M UARS MLS has made unprecedented Aura’s MLS will continue the ClO and HCl quency ranges (millimeter and submillimeter measurements of water vapor in the n MLS is an advanced measurements made by UARS. These measure- 26 km wavelengths). Aura’s MLS is a major techno- lower stratosphere and upper tropo- microwave radiometer logical advance over the MLS flown on UARS. ments will inform us about the rate at which sphere. The tropical measurements that will measure MLS will measure important ozone-destroying stratospheric chlorine is destroying ozone. MLS indicate the year-to-year percentage microwave emission chemical species in the upper troposphere and will also provide the first global measurements variation in water vapor as a difference from the Earth’s limb in stratosphere. In addition, MLS has a unique of the stratospheric hydroxyl (OH) and from the mean value at each level. The upper tropospheric measurement five broad spectral ability to measure trace gases in the presence of hydroperoxy (HO2) radicals that are part of the hydrogen catalytic cycle for ozone destruction. 16 km is possible because MLS can make bands. These bands are ice clouds and volcanic aerosols. NASA’s Jet measurements in the presence of thin In addition, MLS will measure bromine centered at 118 GHz, Propulsion Laboratory (JPL) developed, built, clouds that block infrared measure- tested, and will operate MLS. monoxide (BrO), a powerful ozone-destroying 190 GHz, 240 GHz, 640 ments. Air ascends slowly into the radical. BrO has both natural and man-made stratosphere (above 16 km) carrying GHz, and 2.5 THz. MLS contributes to each of Aura’s three science sources. the water vapor signal from the tropi- questions. A summary of MLS data products cal tropopause upward. n MLS will measure trace appears on page 29. gases at lower altitudes 6 km and with better preci- Earth’s Lower Stratosphere in 1996 Northern and Southern Winters sion and accuracy than WILLIAM READ, “DEHYDRATION IN THE TROPICAL -20 0 +20 TROPOPAUSE LAYER: IMPLICATIONS FROM UARS MLS,” J. its predecessor on UARS. % deviation from mean GEOPHYS. RES., VOL. 109, NO. D6, DOI:10.1029/2003_JD004056, 2004.” MLS will obtain trace gas profiles with a verti- cal resolution of 3 km. MLS measurements of ClO and HCl will be MLS Contributions to especially important in the polar regions. The Understanding Climate Change n MLS pioneers the use HCl measurements tell scientists how stable of planar diodes and chlorine reservoirs are converted to the ozone MLS’s measurements of upper tropospheric monolithic-millimeter destroying radical, ClO. Since the Arctic strat- water vapor, ice content, and temperature wave integrated cir- osphere may now be at a threshold for more will be used to evaluate models and thus reduce the uncertainty in climate forcing. cuits to make the severe ozone loss, Aura’s MLS data will be especially important. MLS also measures greenhouse gases such as instrument more reli- ozone and N O in the upper troposphere. able and resilient to 2 MLS Contributions to launch vibration. MLS Understanding Air Quality looks outward from the oe Waters of the NASA’s Jet Propulsion JLaboratory is Principal Investigator for front of the spacecraft. MLS measures carbon monoxide (CO) and Aura MLS, as he was for UARS MLS. Dr. UKMO T (K) MLS HNO3 (ppbv) MLS ClO (ppbv) MLS O3 (ppmv) ozone in the upper troposphere. CO is an Waters has led the development and MICHELLE SANTEE, IN WATERS, ET AL. “THE UARS AND EOS MICROWAVE LIMB SOUNDER (MLS) EXPERIMENTS,” J. ATMOSPHERIC SCIENCES, VOL. 56, PP 194-218, 15 JAN 1999. important trace gas that can indicate the application of microwave limb sounding since UARS MLS simultaneously mapped key chemical tude range than UARS MLS. Together with exchange of air between the stratosphere and starting it in 1974. His team at NASA’s JPL, constituents nitric acid, chlorine monoxide, and HIRDLS, Aura MLS will measure an array of troposphere. CO is also a tropospheric ozone along with the MLS team at the University ozone over the winter polar regions in both source, radical and reservoir gases in the active precursor and its appearance in the upper tro- of Edinburgh (UK) led by Professor Robert Harwood, is responsible for development of Northern (upper) and Southern (lower) region of the polar stratosphere to give a com- posphere can indicate strong vertical transport the algorithms that generate MLS data prod- Hemispheres where the greatest ozone loss plete picture of the ozone depletion process and from pollution events. occurs. Aura MLS will map these and other predicted recovery. MLS will also make global ucts, monitoring instrument performance, NATHANIEL LIVESEY (NASA JPL) NATHANIEL data processing, validation, and analyses. chemicals with better coverage and larger alti- measurements of BrO, OH and HO2.

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Ozone Monitoring Instrument OMI

OMI INSTRUMENT TEAM

OMI Instrument MI is a nadir viewing spectrometer OMI’s contributes to each of Aura’s three tion from MLS and HIRDLS to produce maps Satellite Ozone Data and Forecast Predict Ozone Hole Breakup Characteristics that measures solar reflected and science questions. A summary of OMI data of tropospheric ozone and nitrogen dioxide. backscattered light in a selected range products appears on page 29. OMI will also measure the tropospheric ozone O KNMI (Royal Netherlands of the ultraviolet and visible spectrum. The precursor formaldehyde. Scientists will use Meteorological Institute) forecast- OMI is an advanced n instrument’s 2600 km viewing swath is per- OMI Contributions to Understanding OMI measurements of ozone and cloud cover ed the unusual splitting of the hyperspectral imaging pendicular to the orbit track, providing com- Stratospheric Ozone to derive the amount of ultraviolet radiation Antarctic ozone hole in spectrometer with a plete daily coverage of the sunlit portion of the (UV) reaching the Earth’s surface. The September 2002. This six-day 114º field of view. Its atmosphere. OMI is Aura’s primary instrument OMI will continue the 34-year satellite ozone National Weather Service will use OMI data to forecast for column ozone on September 25, 2002 used data nadir spatial resolution for tracking global ozone change and will con- record of SBUV and TOMS, mapping global forecast high UV index days for public health ozone change. OMI data will support from the European Space ranges from 13 x 24 tinue the high quality column ozone record awareness. Agency’s Global Ozone Monitoring Congressionally mandated and international km to 24 x 48 km. begun in 1970 by Nimbus-4 BUV. Because Experiment (GOME) with the wind ozone assessments. Using its broad wavelength OMI’s swaths almost OMI has a broader wavelength range and bet- OMI Contributions to Understanding fields obtained from a data ter spectral resolution, OMI will also measure range and spectral resolution, OMI scientists assimilation system. Subsequent touch at the equator so Climate Change column amounts of trace gases important to will be able to resolve the differences among satellite data verified the predic- OMI is able to ozone chemistry and air quality. OMI will map satellite and ground based ozone measure- OMI tracks dust, smoke and industrial aerosols tion. KNMI, NASA and NOAA will [DU] use similar assimilation tech- produce global maps aerosols and estimate ultraviolet radiation ments. OMI will also measure the atmospheric in the troposphere. OMI’s UV measurements column of radicals such as nitrogen dioxide allow scientists to distinguish reflecting and niques with OMI data to make each day. reaching the Earth’s surface. OMI’s horizontal regular forecasts of the amount 150 200 300 400 500 resolution is about four times greater than (NO2) and chlorine dioxide (OClO). absorbing aerosols and thus OMI measure- and distribution of total column n OMI contains two spec- ments will help improve climate models. (DU) TOMS. HENK ESKES (KNMI) ozone. OMI will deliver data three trometers; the first OMI Contributions to Understanding hours after observation. measures the UV in the The Netherlands Agency for Aerospace Pro- Air Quality wavelength range of grams (NIVR) and the Finnish Meteorological Aerosol Optical Depth Tropospheric ozone, nitrogen dioxide, sulfur MI Principal 270-365 nm, while the Institute (FMI) contributed the OMI instru- Investigator Pieternel dioxide, and aerosols are four of the U. S. O ment to the Aura mission. The Netherlands Levelt is a research other spectrometer Environmental Protection Agency’s six criteria measures the visible in companies, Dutch Space and TNO-TPD, scientist at the Royal pollutants. OMI will map tropospheric Netherlands Meteoro- the range of 365 to 500 together with Finnish companies, Patria, VTT 65 N 0.6 and SSF, built the instrument. columns of sulfur dioxide and aerosols. OMI logical Institute (KNMI). nm. Both spectrometers measurements will be combined with informa- Co-Principal Investigators have a bandpass of are Ernest Hilsenrath, Tropospheric Ozone Map from NASA Goddard about 0.5 nm with spec- 55 N 0.4 Space Flight Center

tral sampling ranging KNMI (GSFC), and Gilbert from 0.15 to 0.3 This monthly average map was Leppelmeier, from the made by subtracting the stratos- optical depth nm/pixel, depending Finnish Meteorological Institute. Pawan Bhartia leads pheric ozone column from TOMS 45 N 0.2 the US science team. Bhartia and Hilsenrath have led on wavelength. column ozone. The stratospheric the development and application of UV backscatter column is calculated using UARS techniques for measuring trace gases. These scientists n OMI uses a CCD solid MLS measurements. Higher quality and their teams have overseen OMI instrument develop- state detector array to tropospheric ozone maps on a 35 N 0 ment and are responsible for calibration, developing provide extended spec- daily basis will be produced from 10W 0E 10E 20E 30E algorithms, monitoring instrument performance, data OMI and HIRDLS data. processing, analysis and validation. tral coverage for each OMI will collect data on aerosol optical thickness in the ultraviolet pixel across the meas- with eight times better spatial resolution than TOMS instruments. urement swath. . VEEFKIND AND G. DE LEEUW, IN AUGUST EUROPE OPTICAL DEPTH OVER AEROSOL Optical thickness in the ultraviolet tells scientists whether the aerosols absorb or reflect radiation; this information is necessary 061218 24 30 36 42 48 for climate studies. The figure shows aerosol measurements DU (monthly average, August 1997) by ATSR-2 at an OMI resolution S. CHANDRA AND J. ZIEMKE (BOTH NASA GSFC) of 13 x 24 km. GONZALEZ, C.R., J.P DATA, ATSR-2 1997 DERIVED FROM GEOPHYS. RES. LETT., 27, 955-958, 2000

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Tropospheric Emission Spectrometer TES

TES INSTRUMENT TEAM

TES Instrument ES is an imaging Fourier Transform TES Contributions to Understanding TES Simulated Data Characteristics Spectrometer observing the thermal Stratospheric Ozone T emission of the Earth’s surface and atmosphere, night and day. TES will measure TES limb measurements extend from the Harvard University’s GEOS-CHEM model n TES is a high-resolution tropospheric ozone and of other gases impor- Earth’s surface to the middle stratosphere, and infrared-imaging the TES spectral range overlaps the spectral demonstrates that TES tant to tropospheric pollution. Satellite tropos- will observe the major range of HIRDLS. As a result, TES’s high Fourier Transform pheric chemical observations are difficult to features in tropospheric Spectrometer with make due to the presence of clouds. To over- resolution spectra will allow scientists to ozone on a single day. spectral coverage of come this problem TES was designed to make measurements of some additional The top panel shows 3.2 to 15.4 µm at a observe both downward (in the nadir) and hor- stratospheric constituents as well as improve the GEOS-CHEM simu- HIRDLS measurements of species common lated ozone field at spectral resolution of izontally (across the limb). This observation capability provides measurements of the entire to both instruments. 681 hPa (about 3.1 0.025 cm-1. The instru- km). The white areas lower atmosphere, from the surface to the ment can provide infor- are mountainous stratosphere. NASA’s JPL developed, built, TES Contributions to Understanding mation on essentially regions where the sur- tested, and will operate TES. Air Quality face pressure is below

almost all radiatively UNIVERSITY) (HARVARD ANIEL JACOB D 681 hPa. The ‘+’ signs TES will measure the distribution of gases in active gases in the The TES primary objective is to measure trace on the bottom panel the troposphere. TES will provide simultane- Earth’s lower atmos- gases associated with air quality. A summary indicate Aura’s flight ous measurements of tropospheric ozone and path and the locations of TES data products appears on page 29. phere. key gases involved in tropospheric ozone of TES nadir measure- ments. White areas are TES makes both limb chemistry, such as HNO3 and CO. TES data n found on the flight path and nadir observations. will be used to improve regional ozone pollu- tion models. where clouds obscure In the limb mode, TES the entire TES footprint. has a height resolution The map in the lower Ground Level Ozone panel is constructed of 2.3 km, with cover- from the simulated val- age from 0 to 34 km. In With its pointing capability ues at the ‘+’ loca- the nadir mode, TES has and smal pixel size (5 x 8 tions. The simulated a spatial resolution of km) TES can detect map reproduces many changes in ozone levels in of the features found in 5.3 x 8.5 km. The large urban locations such the original model field.

instrument can be as Los Angeles. The < 1.5150e-08 > 773.30e-08 Ozone Volume Mixing Ratio (ppbv) pointed to any target orange and red areas rep- Ozone Volume Mixing Ratio MINGZHAO LUO (NASA JPL) MINGZHAO within 45 degrees of resent regions of unhealthy ozone levels. The orange the local vertical. area indicates ozone levels einhard Beer of the NASA’s Jet greater than 80 parts per TES Contributions to In order to detect the RPropulsion Laboratory serves as the n billion by volume (ppbv) Understanding Climate Change infrared radiation from Principal Investigator for TES. Beer is a and the red area indicates pioneer in the development and applica- the Earth’s atmos- levels greater than 125 TES will measure tropospheric water vapor, tion of Fourier Transform technology for phere, TES’s detectors ppbv. methane, ozone and aerosols, all of which are remote sensing. Beer and his team are have to be kept at very relevant to climate change. Additional gases responsible for developing the atmospheric important to climate change can be retrieved constituent retrieval algorithms, monitoring cold temperatures. An instrument performance, calibration, data U.S. ENVIRONMENTAL PROTECTION AGENCY (EPA) AGENCY PROTECTION U.S. ENVIRONMENTAL from the TES spectra.

advanced cryogenic KAREN YUEN (NASA JPL) processing and analysis. refrigerator keeps the detectors cool.

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Mission Synergy: Maximizing Science Results

Mission Synergy he Aura instruments were selected and ice clouds. TES limb ozone measurements of Aura’s four instruments. TES provides a ozone directly. The second estimate of the total the satellite was designed to maximize overlap the measurements from HIRDLS and backup for HIRDLS. MLS and HIRDLS both tropospheric ozone amount can be obtained by Tscience impact. The four Aura instru- MLS up to the middle stratosphere. OMI can measure nitric acid and MLS measures HCl subtracting HIRDLS stratospheric ozone meas- Aura measures a full n ments have different fields of view and comple- also make broad ozone profile measurements and chlorine monoxide (ClO), two gases that urements from OMI’s total column ozone range of gases active mentary capabilities. The instruments all using a modified SBUV technique. are transformed by the chemical processes measurements. A similar procedure can be in ozone chemistry. observe the same air mass within about 13 involving aerosols. used to estimate the tropospheric amount of minutes, a short enough time so the chemical To establish the scientific basis for ozone NO , an important ozone precursor. n Aura measures five of 2 and dynamical changes between observations change, scientists must measure the global dis- Air Quality the six EPA criterion are small. tribution of the source, reservoir, and radical In the clear upper troposphere, Aura instru- air pollutants. chemicals in the nitrogen, chlorine, and hydro- Measuring tropospheric ozone and its precursor ments provide overlapping measurements of Stratospheric Ozone gen families. Together, the Aura instruments gases is a major goal for Aura. Aura’s instru- CO (MLS, TES), H O (MLS, TES, HIRDLS), n Aura measures upper ments provide two methods of tracking ozone 2 troposphere ozone and fill this requirement. For example, HIRDLS Understanding stratospheric ozone change measures the halocarbons (chlorine source pollution. First, TES measures tropospheric continues on page 22 water vapor, both impor- involves measurements of both the ozone pro- gases) and chlorine nitrate (one of the major tant contributors to file and the total column amount, as well as chlorine reservoir gases), while MLS measures climate change. the chemicals responsible for ozone change. the radical chlorine monoxide and hydrogen Aura Atmospheric Measurements chloride (the other major chlorine reservoir). All of Aura’s instruments make ozone profile HIRDLS: High Resolution Dynamics Limb Sounder MLS: Microwave Limb Sounder measurements. HIRDLS profiles have the Stratospheric aerosols influence ozone concen- OMI: Ozone Monitoring Instrument TES: Tropospheric Emission Spectrometer 100 highest vertical resolution and extend from trations through chemical processes that trans- 80 cloud tops to the upper stratosphere. MLS form ozone-destroying gases. HIRDLS meas- 50 measurements have lower vertical resolution ures stratospheric aerosols with the best hori- than HIRDLS, but MLS can measure ozone in zontal coverage and highest vertical resolution the presence of aerosols and upper tropospheric 40

30 OH ClONO2 HCl ClO aerosol Fields of View HNO extinction O HO2 CH3 CN 3 NO2 HOCl BrO 25 3 CF Cl volcanic temperature H2O CH4 HCN N2O5 2 2 polar SO2 strato- Fields of view for Aura’s 20 CO N2O CFCl3

Vertical Profiles spheric instruments appear in differ- cloud cloud clrrus geo- top 15 ice potential ent colors: HIRDLS in yellow, height content height OMI in blue, MLS in green, and TES in red. HIRDLS looks 10

backward through the limb 5

and scans the atmosphere’s ight above surface in km (note non-linear scale above 30 km) he vertical profiles across the 0 satellite track. MLS looks aerosol volcanic O3 HCHO NO2 OClO BrO forward through the limb and extinction SO2 Total

scans the atmosphere vertical Columns profiles along the satellite (NASA JPL) JOE WATERS track. OMI looks downward Each of Aura’s four instruments provides unique and cloud top height and coverage. The altitude and has a cross track swath and complementary capabilities to enable daily range for measurement appears as the vertical of 2600 km. TES looks both global observations of Earth's atmospheric ozone scale. In several cases instrument measurements in the nadir and limb and layer, air quality, and climate. The chart (above) overlap, which provides independent perspectives also has off nadir pointing summarizes the specific atmospheric physical and cross calibration. These measurements will capability. properties and chemical constituents measured result in the most comprehensive set of atmos- by each instrument. OMI also measures UVB flux pheric composition ever measured from space. JESSE ALLEN (SSAI)

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If the air is HNO3 (MLS, TES, HIRDLS). Carbon monox- Simulated Tropospheric Ozone Aura and the A-Train ide (CO) is an ozone precursor and HNO3 is a altered ever so reservoir gas for NO2. The combination of slightly, the state TES nadir measurements and MLS limb measurements through clouds will provide of the psychic important new information on the distribution y 2006, Aura will be a member of a aerosols. Aerosol height information obtained Satellite Constellation constellation of satellites flying in by CALIPSO can be combined with data on of CO and H2O. spirit will be Bformation. This formation is referred aerosol size distribution and composition from Aura will fly in a carefully- to as the “A-Train.” Flying with Aura in the PARASOL and Aqua’s MODIS. altered perceptibly. An emerging problem in air quality is the designed constellation of six increasing amount of aerosols in the air we A-Train are Aqua, CloudSat, CALIPSO, and OCO. The French space agency, Centre n What is the role of polar stratospheric Earth-observing satellites Maimonides, breathe. OMI measures aerosols, and distin- guishes between smoke, mineral dust, and National d’Etudes Spatiales (CNES), plans to clouds in ozone loss in the Antarctic that gather concurrent sci- 12th Century other aerosols. Both TES and HIRDLS meas- send a sixth satellite, PARASOL, to join the vortex? ence data in a virtual plat- philosopher ure aerosol characteristics in the upper tropo- A-Train. All six satellites will cross the equator form. Constellation flying sphere to help understand how aerosols are 0Tropospheric Ozone (DU) 100 within a few minutes of one another near 1:30 Aura’s MLS and HIRDLS will provide cloud increases mission capability

transported. ZIEMKE (NASA GSFC) SUSHIL CHANDRA AND JERRY p.m. local time and again in the early morn- height and temperature data, and ozone, nitric while it lowers total mission Atmospheric scientists derive tropospheric ing, about 1:30 a.m. acid and chlorine monoxide concentrations. risk and mission cost. Climate Change ozone amounts by combining measurements CALIPSO measures precise polar stratospheric from different satellites, such as subtracting While each satellite has an independent science cloud height and cloud type. Aura contributes to the Atmospheric chemistry and climate are inti- stratospheric amounts from NASA’s UARS mission, these complementary satellite obser- collective science mission, mately connected. Ozone, water vapor, and MLS or NOAA’s SBUV/2 instruments from vations will enable scientists to obtain more n What is the vertical distribution of cloud particularly with regard to TOMS column amounts. These show how tro- information than they could using the observa- water and ice in upper tropospheric pospheric ozone is transported across conti- questions about the role of tions of a single mission. cloud systems? Completing the Picture of Stratospheric Chemistry nents and oceans. Aura will provide more polar stratospheric clouds accurate tropospheric ozone by subtracting the HIRDLS stratospheric profiles from OMI The A-Train formation allows us to focus on Aura’s MLS will provide water vapor measure- in polar ozone loss, and the column amounts as simulated in this figure. new science questions. For example: ments in the presence of clouds while CloudSat vertical distribution of water The high spatial resolution of these two instru- will measure cloud height. PARASOL will and ice in cloud systems. ments will provide data necessary to quantify n What are the aerosol types and how do provide particle type information while Aqua’s chemical and dynamic processes controlling observations match global emission and MODIS will give particle size information. tropospheric ozone. transport models?

Data from Aura’s OMI will provide informa- N2O take part in tropospheric chemical tion on the global distribution of absorbing processes and are also greenhouse gases. Changes in these and other greenhouse gases can upset the atmosphere’s heat balance and

BARBARA SUMMEY (SSAI) The satellites of the A-Train. alter climate. Measurements of these gases, Chemical and transport processes have led to changes in the stratospheric ozone layer, and scientists need measurements of many different chemical their sources and sinks are essential if we are to species to puzzle out the causes for these observed changes. Measurements understand how the climate is changing as a of ozone-destroying radicals such as ClO, NO2, BrO and OH and reservoir gases result of human activity. All of the Aura CALIPSO Aqua such as N2O5, ClONO2 and HNO3 help solve the chemical part of the puzzle. instruments provide information on tropos- CloudSat Measurements of long-lived gases such as N O and CH tell scientists about 2 4 pheric ozone. PARASOL the puzzling effects of transport. Ozone and some other constituents are meas- ured by all the instruments; some constituents like hydrochloric acid are meas- Clouds and aerosols are also important contrib- ured by only one. New Aura measurements, such as OH, will help us complete OCO utors to climate change. HIRDLS and MLS the picture. The new measurements are shown as detached pieces. Aura will measure cirrus clouds. OMI will measure aerosol distributions and cloud distributions and their heights. ALEX MCCLUNG (SSAI)

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The Aura Spacecraft

Spacecraft Subsystems he Aura spacecraft provides the essential services for operating the four scientific n Structure—Graphite T epoxy composite over instruments over the life of the honeycomb core mission. The spacecraft, based on the EOS Common Spacecraft n Electrical Power— The deployable flat-panel design, was built by Northrop solar array with over Grumman Space Technology and 20,000 silicon solar adapted for the Aura instrument cells provides 4800 payload. watts of power in sunlight and charges a Building a complex spacecraft 24-cell nickel-hydrogen requires an engineering team battery for the night phase of the orbit with a diverse set of technical skills. The team has to translate n Command and Data the scientific requirements of the Spacecraft delivery Handling System—Stores mission into the technical over 100 gigabits of sci- requirements for the spacecraft to entific data on-board assure that when the subsystems n Communications— and instruments are brought X-band (high data rate) together to form the observatory for science data, S-band (spacecraft plus instruments), they (low data rate) for com- function as one cohesive mand and telemetry, via polar ground stations system. n Guidance, Navigation The spacecraft is made up of the and Control—Stellar- following subsystems: command inertial, and momentum wheel-based attitude and data handling; communica- controls tions; electrical power; electrical distribution; guidance, naviga- n Propulsion—System of tion and control; propulsion, four one-pound thrust software and thermal control. Each subsystem Spacecraft assembly hydrazine monopropel- lant rockets requires designers, engineers, analysts and technicians with specialized training. A team n Software—The satellite of integration and test specialists assembles the The Aura observatory will be launched on a systems are managed observatory and tests it as a system, simulating Delta II 7920 rocket from Vandenberg Air by a flight computer the launch and on-orbit environments as close- Force Base in California into a near polar, sun- that is responsible for the health and safety of ly as possible. For example, the spacecraft is synchronous orbit of 438 mi (705 km), with a all the instrument sub- exposed to vibrations similar to what it would period of approximately 100 minutes and a systems experience during launch. As the observatory 1:45 PM equator crossing time. The spacecraft comes together, the flight operations team repeats its ground track every 16 days. learns and practices how to operate the obser- vatory well before launch. Right, Spacecraft descending into thermal GES 24- 25. PHOTOS OF AURA SPACECRAFT COURTESY OF NORTHROP GRUMMAN SPACE TECHNOLOGY GRUMMAN SPACE COURTESY OF NORTHROP GES 24- 25. PHOTOS OF AURA SPACECRAFT

vacuum test chamber, October 2003. PA

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High altitude balloon measurements will provide trace gas profiles Aura Validation for Aura validation.

alidation is the process by which scien- The Aura validation program capitalizes on instruments will provide datasets that will tell for validation, because the UT/LS exhibits tists show that their space-based meas- routine sources of data such as the ozonesonde scientists whether or not the campaign obser- much more spatial and temporal variability Vurements have their expected accuracy. network and the Network for Detection of vations are truly representative of the atmos- (weather) than the middle and upper strato- Validation of Aura measurements involves Stratospheric Change (NDSC). Balloon-borne phere’s chemistry. sphere. The Aura validation program includes making similar atmospheric measurements instruments will measure profiles of stratospheric an instrument development program and field from airplanes, balloons or ground-based sites. constituents up to 25 miles (40 km). Smaller Aura’s focus on the upper troposphere and campaigns between October 2004 and Scientists compare Aura data with calibrated balloons will carry water vapor instruments in lower stratosphere (UT/LS) presents challenges Autumn 2007. measurements collected as the satellite passes the tropics to validate Aura’s measurements of overhead. this important gas. Aircraft flights provide tropospheric profiles of ozone, carbon monoxide, Ground-based radiometers and spectrometers and nitrogen species. Aircraft lidars will measure make column measurements similar to those fly- profiles of ozone and temperature for long ing on Aura. Lidars measure temperature and distances along the satellite track. Scientists some trace gas constituent profiles. Aircraft such will also compare profiles of stratospheric as the DC-8 (medium altitude) and the ER-2 constituents from Aura with those from other (high altitude) carry airborne spectrometers, satellites, including the NASA UARS, the ESA radiometers, and air samplers to measure upper Envisat, and the Canadian SCISAT, and use data atmospheric constituents. assimilation techniques to identify systematic differences among the data sets. Instruments on board the NASA DC-8 will measure tropospheric and lower stratospheric The Aura project has adopted a strategy to trace gases. increase the scientific return from the valida- tion program. Some of the validation activities will be embedded within focused science cam- paigns. These campaigns have been selected to obtain data needed to unravel complex science NASA DFRC questions that are linked to the three main NASA DFRC Aura science goals. Scientists will use the satel- High altitude aircraft will make in situ measurements of stratospher- Unpiloted aerial vehi- lite data to understand the overall chemical ic and tropospheric constituents. Above, the Proteus, and below, the cles (UAVs), such as and meteorological environment during the NASA ER-2 have been frequently used in satellite validation. NASA’s Altair shown campaigns. Aircraft measurements will be used above, will be used in Aura validation to to both validate Aura data and address the make measurements science by making additional measurements. along the satellite track. Aura is This strategy emphasizes the strengths of pioneering the both data sets. Campaign instruments make use of UAVs for constituent measurements that are more com- validation. plete than can be obtained from satellites. Campaign data are obtained for much smaller NOAA CLIMATE MONITORING AND DIAGNOSTICS LABORATORY spatial scales and with high temporal resolu- Ground-based measurements from sites like tion compared to satellite data. Aircraft mis- the one pictured above at Barrow, Alaska, will provide a long time series of constituent sions take place a few times each year at most measurements for validation. and are limited to a small portion of the globe, while the Aura instruments will make global NASA DFRC MARK SCHOEBERL (NASA GFSC) MKIV INTERFEROMETER LAUNCH (NASA JPL) MKIV INTERFEROMETER observations throughout the year. The Aura

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The EOS Aura Ground System NORTHROP GRUMMAN SPACE TECHNOLOGY GRUMMAN SPACE NORTHROP he EOS Aura ground system has two EOC. The data collected by the Aura instru- equally important functions: to operate ments will be recorded onboard the spacecraft Aura Instruments and Data Products T the Aura satellite, and to process, archive and relayed to ground stations in Alaska and and distribute the Aura data. NASA’s EOS Norway when the satellite passes overhead. ACRONYM NAME CONSTITUENT INSTRUMENT DESCRIPTION Data and Information System (EOSDIS) sup- ports both of these. Data Processing, Archive and HIRDLS High Resolution Profiles of T, O3,H2O, Limb IR filter radiometer Distribution Dynamics Limb CH4,N2O, NO2, HNO3, from 6.2 to 17.76 µm Operating the Aura Satellite Sounder N2O5,CF3Cl, CF2Cl2, 1.2 km vertical resolution The data will be transmitted from the ground ClONO2, aerosol up to 80 km Mission operations are based at the NASA stations to the EOS Data and Operations composition Goddard Space Flight Center in Greenbelt, System (EDOS). From there the data for Maryland. The Flight Operations Team at the HIRDLS, MLS and OMI will be sent to the MLS Microwave Limb Profiles of T, H2O, O3, ClO, Microwave limb sounder EOS Operations Center (EOC) will command Goddard Distributed Active Archive Center Sounder BrO, HCl, OH, HO2, HNO3, from 118 GHz to 2.5 THz, and control the Aura spacecraft and instru- (DAAC); data for TES will be sent to the HCN, N2O, CO, cloud ice with 1.5-3 km vertical ments, monitor their health and safety and Langley Research Center (LaRC) DAAC. Each HOCI, CH3CN resolution perform mission planning and scheduling. Science Investigator-led Processing System Instrument teams at NASA’s JPL, University (SIPS) will receive the data from the DAAC OMI Ozone Monitoring Column O3, aerosols, Hyperspectral nadir of Colorado and KNMI, Holland are responsi- for further processing. The SIPS will produce Instrument NO2,SO2, BrO, OClO, HCHO, imager, 114º FOV, ble for day-to-day planning, scheduling, and scientific data such as profiles and column UV-B, cloud top pressure, 270-500 nm, 13x24 km monitoring of their instruments through the amounts of ozone and other important atmos- O3 profiles footprint for ozone and pheric species. Each instrument team will aerosols monitor the data products to ensure that they

are of high quality. The data products will TES Tropospheric Profiles of T, O3,NO2,CO, Limb (to 34 km) and then be sent back to the DAACs where they Emission HNO3,CH4,H2O nadir IR Fourier transform will be archived. The DAACs are responsible Spectrometer spectrometer 3.2-15.4µm for distribution of data to scientists all over Nadir footprint 5.3x8.5 the world. km, limb 2.3 km

Getting the data Researchers, government agencies and educators will have unrestricted access to the Aura data via the EOS data gateway (eos.nasa.gov/imswelcome). Data seekers Man and Nature must work can search for and order data from any of the hand in hand. The throwing EOS DAACs. out of balance of the resources of nature, throws out of balance the lives of men.

F. D. Roosevelt, 1935, President of the United States ANGIE KELLY (NASA GSFC) ANGIE KELLY

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Aura Education and Public Outreach

ASA missions to study the Earth ic chemistry and transport; and the fourth and other planets continue to inspire issue (2005) will focus on Aura results. In asso- Nthe next generation of explorers. ciation with the National Chemistry Week Aura’s three areas of science investigation— theme The Earth’s Atmosphere and Beyond! ACS stratospheric ozone, climate change, and air and NASA have also collaborated to conduct quality—are issues of everyday concern. workshops for teachers at all of the regional Aura investigators have partnered with the National Science Teachers Association meet- Smithsonian Institution, the American ings from 2002 to 2004. Chemical Society, and the GLOBE Program to reach multiple audiences. The Aura team supports the GLOBE Program Students and teachers in Czechoslovakia investigate surface (Global Learning and Observations to Benefit ozone amounts through GLOBE, an international science and Hundreds of thousands of visitors to the the Environment) to involve young researchers education program. Trainers from the U.S. pose with them and Smithsonian Institution’s National Museum of in atmospheric chemistry. More than 13,000 their teacher. Natural History will have the opportunity to kindergarten through 12th grade schools in experience a new permanent exhibit based on 100 countries participate in the GLOBE pro- Aura science, The Atmosphere: Change Is In gram. Aura supported the development of inex- GLOBE students the Air. The new exhibit resides in the Forces pensive instruments to measure UV radiation, measure injury to of Change exhibit hall, where connections surface ozone, and aerosols. GLOBE develops plant leaves for among land, oceans and atmosphere are protocols for students to follow when making ozone air quality explored. Interactive displays immerse visitors measurements and reporting their data. Schools studies. in the early history, evolution, and structure of in the Netherlands are particularly active in the atmosphere. Northrop Grumman Space Aura science observations through a partnership Technology has contributed a one-eighth scale between GLOBE Netherlands and KNMI, the model of the Aura satellite to the exhibit, and OMI PI institute. About 20 Dutch schools plan MS. CERNOCHOVA STENCLOVA DANA the Smithsonian’s Department of Education to become part of the data validation program has developed learning activities for student for Aura. Website Addresses group visits. In association with the exhibit,

the Smithsonian Press will publish a book by The Aura team has published six articles about n See National Museum of Natural History online at: Nobel Prize Winner, Sherwood Rowland, atmospheric science on Earth Observatory, www.nmnh.si.edu/ Atmosphere. NASA’s award-winning website, earthobserva- tory.nasa.gov. The articles include “Ultraviolet n See Chem Matters online at: By the time the Aura satellite achieves orbit, Radiation: How It Affects Life on Earth”; www.acs.org/education/curriculum/chemmatt.html every high school chemistry teacher in the “Highways of a Global Traveler”; and United States will have received four special “Watching Our Ozone Weather”. About n See the GLOBE Program online at: issues of the high school magazine, Chem 300,000 individuals visit this website each www.globe.gov/fsl/welcome/welcomeobject.pl Matters, devoted to Aura mission science, month, and 36,000 subscribe to a weekly mathematics, engineering, and technology. update. More articles, including one on scien- n For current information on education opportunities, visit the Aura The American Chemical Society (ACS) and tist-teacher-student partnerships, are under website at: NASA collaborated in the production of these development. eos-aura.gsfc.nasa.gov magazines. The first issue (2001) introduces students to the Aura mission itself; the second For current information on education opportu-

issue (2002) portrays the professional and per- nities, visit the Aura website at: (KNMI) DEN BOVENKAMP JOKE VAN sonal lives of the people who make Aura possi- A GLOBE teacher and students learn how ble; the third issue (2003) explores atmospher- eos-aura.gsfc.nasa.gov to measure aerosols with a hand-held sun photometer.

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Acknowledgements

Goddard Project Office R. Pickering, J. Bolek, C. Dent, M. Domen, M. Fontaine, G. Jackson, J. Lohr, J. Loiacono, S. Manning, K. McIntyre, A. Razzaghi

NASA HQ Program Office

P. DeCola, D. Anderson , J. Gleason, M. Kurylo, M. Tanner JESSE ALLEN (SSAI)

Chemicals Project Science Office BrO Bromine monoxide ClONO2 Chlorine nitrate HNO3 Nitric acid NOx Nitrogen oxide M. Schoeberl, A. Douglass, and E. Hilsenrath CF2Cl2 Dichlorodifluoromethane CO Carbon monoxide HO2 Hydroperoxy radical O2 Oxygen This brochure is CFCl3 Trichlorofluoromethane CO2 Carbon dioxide HOCl Hypochlorous acid O3 Ozone CH CN Methyl cyanide H 0Water N ONitrous oxide OClO Chlorine dioxide dedicated to Science Teams 3 2 2 CH Methane HCl Hydrogen chloride N O Dinitrogen pentoxide OH Hydroxyl HIRDLS 4 2 5 the memory of Cl Chlorine HCHO Formaldehyde NO Nitric oxide SO2 Sulfur dioxide U. S. A. Team: L. Avallone, B. Boville, G. Brasseur, M. Coffey, T. Eden, D. Edwards , D. Kinneson, A. Lambert, ClO Chlorine monoxide HCN Hydrogen Cyanide NO Nitrogen dioxide Professor James Reed C. Leovy, B. Nardi , C. Randall, W. Randel , B. Toon 2 U. K. Team: D. Andrews, R. Harwood, M. McIntyre, H. Muller, C. Mutlow, A. O’Neill, J. Pyle, C. Rodgers, Acronyms Holton (1938-2004), F. Taylor, G. Vaughan, R. Wells, J. Whitney, E. Williamson ACS American Chemical Society NASA National Aeronautics and Space Administration an inspirational MLS ASTER Advanced Spaceborne Thermal Emission and Reflection Radiometer NCAR National Center for Atmospheric Research ASTR Along Track Scanning Radiometer NDSC Network for the Detection of Stratospheric Change U. S. A. Team: R. E. Cofield, L. Froidevaux, R. Jarnot, N. Livesey, G. Manney, H. Pickett, W. Read, M. Santee, atmospheric scientist BUV Backscatter Ultraviolet Instrument NGST Northrop Grumman Space Technology P. Siegel, J. Waters, D. Wu CALIPSO Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Nimbus 7 NASA satellite, operated from 1978-1994 carrying a and a member of the U. K. Team: M. J. Filipiak, R. Harwood, H. Pumphrey CCD Charge Coupled Device TOMS instrument UARS and Aura OMI CFC Chlorofluorocarbon Nimbus-4 NASA satellite,operated from 1970-1980 carrying the BUV instrument NOAA National Oceanic and Atmospheric Administration Dutch team: B. van den Oord, J. Claas, M. Dobber, M. Kroon, P. Veefkind, S. van Broekhoven, CNES Centre National d'Etudes Spatiales Science Teams. OCO Orbiting Carbon Observatory J. van den Bovenkamp, E. Brinksma, J. de Haan, R. Dirksen, R. Noordhoek, R. Voors DAAC Distributed Active Archive Center DFRC Dryden Flight Research Center OMI Ozone Monitoring Instrument (One of the four Aura instruments) Jim Holton made Finnish Team: G. Leppelmeier, A. Mälkki, E. Kyrö, A. Tanskanen DU Dobson Unit OMPS Ozone Mapping Profiler Suite U. S. A. Team: P. Bhartia, R. Cebula, K. Chance, D. Cunnold, J. Fishman, A. Fleig, L. Flynn, J. Gleason, countless EOC EOS Operations Center PARASOL Polarization and Anisotropy of Réflectances for Atmospheric Sciences D. Heath E. Hilsenrath, J. Joiner, A. Krueger, R. McPeters, G. Mount, S. Sander,I. Stajner, O. Torres, coupled with Observations from a Lidar EOS Earth Observing System contributions C. Trepte ppbv Parts per billion volume EOSDIS Earth Observing System Data and Information System International team: I. Isaksen, D. Hauglustaine, U. Platt, P. Simon, I. Aben, F. Denterer, H. Kelder, P. Stammes, SAGE Stratospheric Aerosol and Gas Experiment to atmospheric science EPA Environmental Protection Agency D. Swart, G. de Leeuw, F. Boersma, R. van Oss SBUV Solar Backscatter Ultraviolet ESA European Space Agency and enriched the lives SCIAMACHY Scanning Imaging Absorption Spectrometer for TES GISS Goddard Institute for Space Studies Atmospheric Cartography GLOBE Global Learning and Observations to Benefit the Environment of his students and U. S. A. Team: S. Clough, M. Gunson, D. Jacob, J. Logan, F. Murcray, D. Rider, C. Rinsland, , S. Sander, SIPS Science Investigator Processing Systems H. Worden GOME Global Ozone Monitoring Experiment SSAI Science Systems & Applications, Inc. colleagues. GSFC Goddard Space Flight Center U. K. Team: C. Rodgers, F. Taylor TES Tropospheric Emission Spectrometer (One of the four Aura HALOE Halogen Occultation Experiment, instrument on UARS satellite instruments) HIRDLS High Resolution Dynamics Limb Sounder (One of the four Aura TOMS Total Ozone Mapping Spectrometer Brochure Team instruments) UARS Upper Atmosphere Research Satellite Authors: Ernest Hilsenrath, Mark R. Schoeberl, and Anne Douglass (NASA GSFC) JPL Jet Propulsion Laboratory UK United Kingdom KNMI Royal Dutch Meteorological Institute Project Coordinator: Stephanie Stockman (SSAI) UMBC University of Maryland Baltimore County MLS Microwave Limb Sounder (One of the four Aura instruments) Designer: Ellen Baker Smyth, Elle Designs UV Ultraviolet MODIS Moderate-resolution Imaging Spectroradiometer Contributing Writer/Editor: Jeannie Allen (SSAI) VOC Volatile Organic Compound MOPITT Measurements of Pollution in the Troposphere

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