DOCSLIB.ORG

Miami, Florida AOML Science Program Assessed During

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Miami, Florida AOML Science Program Assessed During Miami,Miami, FloridaFlorida AOMLAOMLKeynotes March-April 2008 Atlantic Oceanographic and Meteorological Laboratory Volume 12, Number 2 The contributions of the following individuals AOML Science Program Assessed during Quadrennial Review were instrumental to the success of AOML’s February and March were busy months at AOML as the Laboratory prepared for a quadrennial science review: critical assessment of its science program. On March 18-20th, five reviewers and several invited guests including Drs. Richard Spinrad and Alexander MacDonald of NOAA’s Climate Research Presentations: •Molly Baringer–Meridional Overturning Office of Oceanic and Atmospheric Research (OAR) visited AOML to participate in the Circulation Laboratory’s quadrennial science review. AOML Director Dr. Robert Atlas began the proceedings by presenting an organiza- •David Enfield–Large Scale Climate Dynamics tional overview of the Laboratory, followed by an overview of AOML’s three science divisions presented by Drs. Silvia •Chunzai Wang–Climate and Atlantic Garzoli, Frank Marks, and John Hurricane Activity Proni. •Gustavo Goni–Global Ocean Variability Reviewers were tasked with and Trends evaluating AOML’s science •Rick Lumpkin–Upper Ocean Dynamics program based upon three research themes derived from the mission Ecosystem Research Presentations: •Rik Wanninkhof–The AOML Ocean Carbon goals of NOAA’s Strategic Plan: Program oceans and climate, coastal ecosystems, and hurricanes. •James Hendee–Integrating Near Real-Time Data for Coral Reef Ecosystem Forecasting Science presentations for each theme (see shaded box to the left) Photo courtesy of Robert Houze •Christopher Kelble–The NOAA/AOML South were tailored to address a series Florida Ecosystem Restoration Program AOML Director Dr. Robert Atlas (left), invited guests, of key questions aimed at reviewers, and staff converge in the first-floor conference •Jia-Zhong Zhang–Nutrient Dynamics in the demonstrating the quality of the room during the three-day evaluation of AOML’s science Ocean research performed, its relevance program. •Elizabeth Johns–Connectivity of the South to NOAA and the nation, and its overall effectiveness in terms of advancing scientific Florida Coral Reef Ecosystem to Upstream understanding, leadership, planning, and transition into operational application. A poster Waters of the Western Caribbean and Gulf session, as well as a question and answer period with the reviewers, followed the formal of Mexico presentations for each research theme. •Christopher Sinigalliano–The AOML Scientific reviews are performed by NOAA to evaluate the quality, relevance, and Environmental Microbiology Program effectiveness of research conducted at OAR laboratories to both internal and external Hurricane Research Presentations: interests, and to help strategically position the laboratories in planning their future science. •Jason Dunion–Physical Processes of The reviews are also intended to ensure that OAR laboratory research is linked to NOAA’s Hurricane Intensity Change strategic plan, relevant to the NOAA Research mission and priorities, and consistent •Mark Powell–Hurricane Impacts with NOAA planning, programming, and budgeting. Preparations for the review were organized and coordinated by Judith Gray and Erica •Sim Aberson–Hurricane Track Improvements Rule of AOML’s Office of the Director. Additionally, AOML’s administrative, scientific, •Robert Rogers–Evaluation of Numerical technical, and maintenance staff all contributed to the successful endeavor. The time, Models to Improve Prediction of Hurricane attention, and efforts of the review team—Drs. Douglas Luther (University of Hawaii), Intensity Change Steven Murawski (NOAA-National Marine Fisheries Service), James Miller (Rutgers • Sundararaman Gopalakrishnan–Hurricane University), Robert Houze (University of Washington), and Ramesh Kakar (National Intensity Model Improvements Aeronautics and Space Administration)—are gratefully acknowledged and appreciated. AOML is an environmental research laboratory of NOAA’s Office of Oceanic and Atmospheric Research located on Virginia Key in Miami, Florida Recent AOML Publications Southern Ocean Cruise Probes Climate-Relevant Gases ELIPOT, S., and R. LUMPKIN, 2008: More than 30 scientists, including a small group from AOML’s Ocean Chemistry Spectral description of oceanic near- Division, embarked on a research cruise aboard the NOAA Ship Ronald H. Brown in surface variability. Geophysical Research February to study how gases important to climate change move between the atmosphere Letters, 35(2):L05606, doi:10.1029/ and the ocean under high winds and seas. The Southern Ocean Gas Exchange Experiment 2007GL032874. was co-sponsored by the National Aeronautics and Space Administration, NOAA, and Johns, W.E., L.M. Beal, M.O. BARINGER, J.R. the National Science Foundation. Molina, S.A. Cunningham, T. Kanzow, and The Brown departed Punta Arenas, Chile near the southern tip of South America on D. Rayner, 2008: Variability of shallow February 29th to cruise the turbulent waters of the Southern Ocean, which surrounds and deep western boundary currents off Antarctica. Amidst roaring winds, rolling waves, and frigid temperatures, scientists the Bahamas during 2004-2005: Results measured turbulence, waves, bubbles, ocean temperature, and ocean color to determine from the 26°N RAPID-MOC array. how these factors relate to the Journal of Physical Oceanography, 38(3):605-623. exchange of carbon dioxide and other climate-relevant gases. Levine, N.M., S.C. Doney, R. WANNINKHOF, “The Southern Ocean is the K. Lindsay, and I.Y. Fung, 2008: Impact largest ocean region where the of ocean carbon system variability on the surface waters directly connect detection of temporal increases in anthro- to the ocean’s interior currents, pogenic CO2. Journal of Geophysical Research, 113(C3):C03019, doi: providing a pathway into the 10.1029/2007JC004153. deep sea for carbon dioxide released from human activ- Mainelli, M., M. DeMaria, L.K. Shay, and G. ities,” said Christopher Sabine, GONI, 2008: Application of oceanic heat an oceanographer at NOAA’s content estimation to operational forecasting of recent Atlantic category Pacific Marine Environmental Laboratory in Seattle, Washing- 5 hurricanes. Weather and Forecasting, Scientists from 22 universities and research institutions 23(1):3-16. ton and co-chief scientist on the cruised the turbulent waters of the Southern Ocean aboard cruise. “Understanding how the NOAA Ship Ronald H. Brown to study how greenhouse MANZELLO, D.P., 2008: Short and long- atmospheric carbon dioxide is gases like carbon dioxide are transferred between the term ramifications of climate change atmosphere and the ocean. upon coral reef ecosystems: Case studies absorbed into these cold surface across two oceans. Ph.D. thesis, University waters under high wind speeds is important for determining how the ocean uptake of of Miami, Rosenstiel School of Marine carbon dioxide will respond to future climate change.” and Atmospheric Science, 82 pp. The world’s oceans are estimated to absorb about two billion metric tons of carbon dioxide from the atmosphere every year. NOAA’s leading research on ocean acidification MURILLO, S.T., 2008: Determination of the resulting from carbon dioxide uptake indicates that many organisms that support marine circulation center and inner core evolution of Hurricane Danny (1997) using the biodiversity may be threatened by climate change in the future. Scientists know that GBVTD-simplex algorithm. M.S. thesis, higher wind speeds promote a faster exchange of gases, but there have been very few University of Hawaii at Manoa, 57 pp. studies aimed at directly measuring these exchanges under real world conditions where other factors, like breaking waves, can influence the process. Pu, Z., X. Li, C.S. Velden, S.D. ABERSON, In spite of the challenging conditions, an unprecedented number of measurements and W.T. Liu, 2008: The impact of aircraft dropsonde and satellite wind data on were gathered during the cruise which should help determine the processes that control numerical simulations of two landfalling air-sea gas exchange. “Our ongoing efforts to understand the global carbon cycle will tropical storms during the Tropical Cloud benefit from the data this cruise produced about the mechanisms that govern gas transfer Systems and Processes Experiment. in this remote part of the world’s ocean,” said Paula Bontempi, manager of NASA’s Weather and Forecasting, 23(1):62-79. ocean biology and biogeochemistry research program. “We directly assessed the rate and mechanism by which the ocean takes up carbon Serafy, J.E., C.R. KELBLE, T.R. Capo, S.A. Luthy, and P.B. ORTNER, 2008: Vertical and releases it,” said co-chief scientist David Ho of the Lamont-Doherty Earth movement rates of captive larval Observatory of Columbia University in Palisades, New York. “This is the first U.S.-led billfishes (Istiophoridae) collected from the effort to use all of the state-of-the-art tools that we have to quantify gas exchange in the Straits of Florida. Florida Scientist, Southern Ocean.” Data gathered during the six weeks at sea are expected to eventually 71(1):23-30. improve the accuracy of climate models and predictions. The cruise ended in Montevideo, UHLHORN, E.W., 2008: Gulf of Mexico Uruguay on April 12th. Loop Current mechanical energy and Adapted from an online article appearing on the NOAA web site. vorticity response to a tropical cyclone. Ph.D. thesis, University of Miami, NOAA’s FY-2008 Information Technology Security
Load more

Recommended publications
  • The Detection of Mesoscale Convective Systems by the GPM Ku-Band Spaceborne Radar
    For Peer Review The Detection of Mesoscale Convective Systems by the GPM Ku-band Spaceborne Radar Journal: Journal of the Meteorological Society of Japan Manuscript ID JMSJ-2019-0034.R1 Manuscript Type: Articles Date Submitted by the n/a Author: Complete List of Authors: wang, jingyu; Pacific Northwest National Laboratory, Atmospheric Sciences & Global Change Houze, Robert ; University of Washington, Department of Atmospheric Sciences; Pacific Northwest National Laboratory, Atmospheric Sciences and Global Change Division Fan, Jiwen; Pacific Northwest National Laboratory, Atmospheric Sciences and Global Change Division Brodzik, Stacy; University of Washington, Department of Atmospheric Sciences Feng, Zhe; Pacific Northwest National Laboratory, Atmospheric Sciences and Global Change Division Hardin, Joseph; Pacific Northwest National Laboratory, Atmospheric Sciences and Global Change Division GPM evaluation, 3D reflectivity structure, Mesoscale Convective System Keywords: tracking, MCS feature, Global MCS distribution, Intense convection Page 1 of 100 For Peer Review 1 The Detection of Mesoscale Convective Systems by the 2 GPM Ku-band Spaceborne Radar 3 4 Jingyu Wang 5 Pacific Northwest National Laboratory, 6 Richland, Washington, USA 1 7 Robert. A. Houze, Jr 8 University of Washington, 9 Seattle, Washington, USA 10 Pacific Northwest National Laboratory, 11 Richland, Washington, USA 12 Jiwen Fan 13 Pacific Northwest National Laboratory, 14 Richland, Washington, USA 15 Stacy. R. Brodzik 16 University of Washington, 17 Seattle, Washington, USA 18 Zhe Feng 19 Pacific Northwest National Laboratory, 20 Richland, Washington, USA 21 and 22 Joseph C. Hardin 23 Pacific Northwest National Laboratory, 24 Richland, Washington, USA 25 26 27 March 31, 2019 28 ------------------------------------ 29 1) Corresponding author: Robert Houze, University of Washington, Seattle, Washington, 30 USA.
    [Show full text]
  • Atmospheric Circulation Newsletter of the University of Washington Atmospheric Sciences Department
    Autumn 2017 Atmospheric Circulation Newsletter of the University of Washington Atmospheric Sciences Department Studying the effects of Southern African biomass burning on clouds and climate: The ORACLES mission by Professor Robert Wood, Michael Diamond, & Sarah Doherty iny aerosol particles, emitted by Fires, mainly associated with dry season Teverything from tailpipes to trees, float agricultural burning on African savannas, above us reflecting sunlight, seeding clouds and generate smoke, a chemical soup that absorbing solar heat. How exactly this happens includes a large quantity of tiny aerosol – and how it might change in the future particles. This smoke rises high in – is one of the biggest uncertainties the atmosphere driven by strong in how humans are influencing surface heating and then is climate. blown west off the coast; it In September 2016, three then subsides down toward University of Washington the cloud layer over the scientists took part in a southeastern Atlantic large NASA field campaign, Ocean. The interaction Observations of Aerosols between air moisture and Above Clouds and their smoke pollution is complex Interactions, or ORACLES, and not well understood. that is flying research planes Southern Africa produces around clouds off the west coast almost a third of the Earth’s of southern Africa to see how smoke biomass burning aerosol particles, particles and clouds interact. yet the fate of these particles and their ORACLES is a five year program, with influence on regional and global climate is three month-long aircraft field studies, and is poorly represented in climate models. led by Dr. Jens Redemann from NASA Ames The ORACLES experiment is providing Research Center in California.
    [Show full text]
  • AMMA-Weather
    Multi-scale Observations and Modeling of West African Tropical Rainfall Systems: AMMA-Weather Principal Investigators: Chris D. Thorncroft SUNY at Albany Chris Davis NCAR Robert A. Houze University of Washington Richard H. Johnson Colorado State University Steven A. Rutledge Colorado State University Bradley F. Smull University of Washington PROJECT OVERVIEW Executive Summary AMMA-Weather is designed to improve both fundamental understanding and weather prediction in the area of the West African monsoon through deployment of U.S. surface and upper-air observing systems in July and August 2006. These systems will be closely coordinated with International AMMA. The project will focus on the interactions between African easterly waves (AEWs) and embedded Mesoscale Convective Systems (MCSs) including the key role played by microphysics and how this is impacted by aerosol. The pronounced zonal symmetry, ubiquitous synoptic and mesoscale systems combined with the close proximity of the Saharan aerosol make the WAM an ideal natural laboratory in which to carry out these investigations. The observations will provide an important testbed for improving models used for weather and climate prediction in West Africa and the downstream breeding ground for hurricanes in the tropical Atlantic. The international AMMA program consists of scientists from more than 20 countries in Africa, Europe, and the US. Owing to the efforts of European countries, a strong infrastructure is being installed providing a unique opportunity for US participation. Support in excess of twenty million Euros has already been secured by Europeans for AMMA including the 2006 field campaign. Significantly for AMMA-Weather, this will include support for the U.S.
    [Show full text]
  • Leading and Trailing Anvil Clouds of West African Squall Lines
    1114 JOURNAL OF THE ATMOSPHERIC SCIENCES VOLUME 68 Leading and Trailing Anvil Clouds of West African Squall Lines JASMINE CETRONE AND ROBERT A. HOUZE JR. Department of Atmospheric Sciences, University of Washington, Seattle, Washington (Manuscript received 10 June 2010, in final form 5 January 2011) ABSTRACT The anvil clouds of tropical squall-line systems over West Africa have been examined using cloud radar data and divided into those that appear ahead of the leading convective line and those on the trailing side of the system. The leading anvils are generally higher in altitude than the trailing anvil, likely because the hydrometeors in the leading anvil are directly connected to the convective updraft, while the trailing anvil generally extends out of the lower-topped stratiform precipitation region. When the anvils are subdivided into thick, medium, and thin portions, the thick leading anvil is seen to have systematically higher reflectivity than the thick trailing anvil, suggesting that the leading anvil contains numerous larger ice particles owing to its direct connection to the convective region. As the leading anvil ages and thins, it retains its top. The leading anvil appears to add hydrometeors at the highest altitudes, while the trailing anvil is able to moisten a deep layer of the atmosphere. 1. Introduction layer ascent (Zipser 1969, 1977; Houze 1977; Houze et al. 1989). We take advantage of a set of data collected at Satellite data show that a large portion of upper-level- Niamey, Niger, as part of the African Monsoon Multi- cloud ice clouds in the tropics originate as anvil clouds disciplinary Analyses (AMMA) field program of summer associated with precipitating deep convection (Luo and 2006 (see Redelsperger et al.
    [Show full text]
  • The Olympic Mountains Experiment (Olympex)
    THE OLYMPIC MOUNTAINS EXPERIMENT (OLYMPEX) ROBERT A. HOUZE JR., LYNN A. MCMURDIE, WALTER A. PETERSEN, MATHEW R. SCHWAllER, WIllIAM BACCUS, JESSICA D. LUNDQUIST, CLIFFORD F. MASS, BART NIJSSEN, STEVEN A. RUTLEDGE, DAVID R. HUDAK, SIMONE TANEllI, GERALD G. MACE, MICHAEL R. POEllOT, DENNIS P. LETTENMAIER, JOSEph P. ZAGRODNIK, ANGELA K. ROWE, JENNIFER C. DEHART, LUKE E. MADAUS, AND HANNAH C. BARNES OLYMPEX is a comprehensive field campaign to study how precipitation in Pacific storms is modified by passage over coastal mountains. hen frontal systems pass over midlatitude the lee sides. Snow deposited at high elevations by mountain ranges, precipitation is modified, these storms is an important form of water storage Woften with substantial enhancement on the around the globe. However, precipitation over and windward slopes and reduced accumulations on near Earth’s mountain ranges has long been very difficult to measure. As a result, the physical and dynamical mechanisms of enhancement and reduc- AFFILIATIONS: HOUZE, MCMURDIE, LUNDQUIST, MASS, NIJSSEN, tion of precipitation accompanying storm passage ZAGRODNIK, ROWE, AND DEHART—University of Washington, over mountains remain only partially understood. Seattle, Washington; PETERSON—NASA Marshall Space Flight Center, Huntsville, Alabama; SCHWAllER—NASA Goddard Space The launch of the Global Precipitation Measurement Flight Center, Greenbelt, Maryland; HOUZE AND BARNES—Pa- (GPM) satellite in February 2014 by the U.S. National cific Northwest National Laboratory, Richland, Washington; Aeronautics and Space Administration (NASA) and BACCUS—Olympic National Park, Port Angeles, Washington; the Japan Aerospace Exploration Agency (Hou et al. RUTLEDGE—Colorado State University, Fort Collins, Colorado; 2014) fosters exploration of precipitation processes HUDAK—Environment and Climate Change Canada, King City, over most of Earth’s mountain ranges.
    [Show full text]
  • Atmospheric Circulation Newsletter of the University of Washington Atmospheric Sciences Department
    Autumn 2012 Atmospheric Circulation Newsletter of the University of Washington Atmospheric Sciences Department The Weather Challenge by Lynn McMurdie he UW Atmospheric Sciences spring Tforecast contest has been an annual tradition in the department for many years. It’s a time when faculty and students alike agonize over whether there will be a marine push or a convergence zone wrecking their forecast for maximum temperature and precipitation probability at SeaTac. The winner earns department-wide recognition with their name engraved on a trophy, and the respect (or envy!) of their fellow forecasters. Now imagine forecasting for a wide-variety of cities across the United States and competing against thousands of other contestants from many other universities and institutions across the country. That’s just what a group of intrepid undergraduate and graduate students did this past year. For the first time, University of Washington entered a team in the national WxChallenge. The WxChallenge contest was developed A few of this year’s participants. From left: Xiaojuan Liu, Jack Neukirchen, Hannah Barnes, by the University of Oklahoma and officially started in 2006 when it replaced the National Jen DeHart, Elizabeth Maroon, Lynn McMurdie, Magdalena Szabo and Ken Dixon. Collegiate Weather Forecast contest. The goal of challenges. Often impromptu discussions would slipped into 3rd place. Aaron Hill, a recent 2012 the WxChallenge is to make the best forecast of erupt in the computer lab or someone’s office grad, had the top score in the nation for wind the next day’s maximum temperature, minimum when tricky forecasts were looming overhead at Riverton, WY.
    [Show full text]
  • Atmospheric Circulation Newsletter of the University of Washington Atmospheric Sciences Department
    Autumn 2016 Atmospheric Circulation Newsletter of the University of Washington Atmospheric Sciences Department OLYMPEX: Testing a NASA Satellite on the Olympic Peninsula by Dr. Lynn McMurdie and Professor Robert A. Houze, Jr. It’s early October 2015, and NASA is project to test a new precipitation measuring satellite, and scientists from the Departments of Atmospheric Sciences and Civil and Environmental Engineering are leading this massive adventure. There is no need for earplugs to protect your ears from the roar of rockets or a countdown: the Olympic Mountains Experiment (OLYMPEX) is being launched by a mule train. mountains and nearby ocean. Highly specialized radars were set up at several locations on both sides of the mountains. For over three years, Houze and Center, McMurdie worked with NASA were planned and colleagues, wrote plans, explored directed. Often 2-3 air craft were in the air at instruments in remote areas, radars on the coast and inland, and locations for aircraft patterns. McMurdie directed a staging. Two aircraft stationed at McChord team of graduate student forecasters, who Mules carry OLYMPEX instruments through wilderness to the high terrain of the Olympic Mts. were crucial for deciding the exact times to the storms with cloud instruments to measure launch the aircraft, operate radars and launch OLYMPEX occurred last fall and winter and the sizes and types of rain and snow particles. soundings. The lead graduate student forecaster was led by Prof. Houze and Dr. McMurdie of To realize this plan, McMurdie and Houze was Jennifer DeHart of the Department of the Department of Atmospheric Sciences.
    [Show full text]
  • Atmospheric Circulation Newsletter of the University of Washington Atmospheric Sciences Department
    Autumn 2011 Atmospheric Circulation Newsletter of the University of Washington Atmospheric Sciences Department Making of the YouTube Can Crushing Video by Kelly McCusker he Department of Atmospheric Sciences and boiled down to the essential information, all brief departure to smooth jazz while the Safety TOutreach group has recently ventured while remaining within the story arc and incor- Chicken shared his safety message. into a bold new frontier: YouTube. Composed porating some humor. “Due to recent advances The rest of the crew for this video included: of faculty, staff, and students, our group has in de-cylindrification theory, the power to crush Bryce Harrop, Brian Smoliak, Jack Scheff, and been volunteering time for over 20 years, shar- cans without undue physical exertion is now in yours truly, with new additions for upcoming ing science with youth on visits to the depart- the power of everyday citizens like yourself!” videos. The process was exceptionally fun, but ment, demonstrating concepts relevant to the Pure genius! We had lots of fun coming up with we did run across some pitfalls, many of which atmosphere, and generally illustrating the won- everyone’s lines. Can you pick out the lines that the group has since corrected. In order to cre- ders of our field. ate high definition video, we now utilize an reference an early 90’s song? In early 2009, the outreach group was HD video camera from the UW Student Tech Step three: filming. We used the department approached by UW’s Joint Institute for the Fee equipment office. We also now focus on Study of the Atmosphere and Ocean (JISAO) to video camera, providing us the flexibility to maintaining consistent audio throughout (care- participate in their Science in 180 initiative.
    [Show full text]
  • Variability of Vertical Structure of Precipitation with Sea Surface Temperature Over the 2 Arabian Sea and the Bay of Bengal As Inferred by TRMM PR Measurements
    1 1 Variability of vertical structure of precipitation with sea surface temperature over the 2 Arabian Sea and the Bay of Bengal as inferred by TRMM PR measurements 3 Kadiri Saikranthi1, Basivi Radhakrishna2, Thota Narayana Rao2 and 4 Sreedharan Krishnakumari Satheesh3 5 1 Department of Earth and Climate Science, Indian Institute of Science Education and 6 Research (IISER), Tirupati, India. 7 2 National Atmospheric Research Laboratory, Department of Space, Govt. of India, Gadanki 8 - 517112, India. 9 3 Divecha Centre for Climate Change, Centre for Atmospheric and Oceanic Sciences, Indian 10 Institute of Science, Bangalore - 560012, India. 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Address of the corresponding author 31 Dr. K. Saikranthi, 32 Department of Earth and Climate Science, 33 Indian Institute of Science Education and Research (IISER), 34 Tirupati, 35 Andhra Pradesh, India. 36 Email: [email protected] 2 37 Abstract 38 Tropical rainfall measuring mission precipitation radar measurements are used to 39 examine the variation of vertical structure of precipitation with sea surface temperature (SST) 40 over the Arabian Sea (AS) and Bay of Bengal (BOB). The variation of reflectivity and 41 precipitation echo top with SST is remarkable over the AS but small over the BOB. The 42 reflectivity increases with SST (from 26°C to 31°C) by ~1 dBZ and 4 dBZ above and below 43 6 km, respectively, over the AS while, its variation is < 0.5 dBZ over the BOB. The 44 transition from shallow storms at lower SSTs (≤ 27°C) to deeper storms at higher SSTs is 45 strongly associated with the decrease in stability and mid-tropospheric wind shear over the 46 AS.
    [Show full text]
  • Diurnally Modulated Cumulus Moistening in the Preonset Stage of the Madden–Julian Oscillation During DYNAMO*
    1622 JOURNAL OF THE ATMOSPHERIC SCIENCES VOLUME 72 Diurnally Modulated Cumulus Moistening in the Preonset Stage of the Madden–Julian Oscillation during DYNAMO* JAMES H. RUPPERT JR. AND RICHARD H. JOHNSON Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado (Manuscript received 28 July 2014, in final form 28 November 2014) ABSTRACT Atmospheric soundings, radar, and air–sea flux measurements collected during Dynamics of the Madden–Julian Oscillation (DYNAMO) are employed to study MJO convective onset (i.e., the transition from shallow to deep convection) in the tropical Indian Ocean. The findings indicate that moistening of the low–midtroposphere during the preonset stage of the MJO is achieved by simultaneous changes in the convective cloud population and large-scale circulation. Namely, cumuliform clouds deepen and grow in areal coverage as the drying by large-scale subsidence and horizontal (westerly) advection wane. The reduction of large-scale subsidence is tied to the reduction of column radiative cooling during the preonset stage, which ultimately links back to the evolving cloud population. While net column moistening in the preonset stage is tied to large-scale circulation changes, a new finding of this study is the high degree to which the locally driven diurnal cycle invigorates convective clouds and cumulus moistening each day. This diurnal cycle is manifest in a daytime growth of cumulus clouds (in both depth and areal coverage) in response to oceanic diurnal warm layers, which drive a daytime increase of the air–sea fluxes of heat and moisture. This diurnally modulated convective cloud field exhibits prominent mesoscale organization in the form of open cells and horizontal convective rolls.
    [Show full text]
  • Morphology, Intensity, and Rainfall Production of MJO Convection: Observations from DYNAMO Shipborne Radar and TRMM
    FEBRUARY 2015 X U A N D R U T L E D G E 623 Morphology, Intensity, and Rainfall Production of MJO Convection: Observations from DYNAMO Shipborne Radar and TRMM WEIXIN XU AND STEVEN A. RUTLEDGE Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado (Manuscript received 1 May 2014, in final form 16 September 2014) ABSTRACT This study uses Dynamics of the Madden–Julian Oscillation (DYNAMO) shipborne [Research Vessel (R/V) Roger Revelle] radar and Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) datasets to investigate MJO-associated convective systems in specific organizational modes [mesoscale convective system (MCS) versus sub-MCS and linear versus nonlinear]. The Revelle radar sampled many ‘‘climatological’’ aspects of MJO convection as indicated by comparison with the long-term TRMM PR statistics, including areal-mean 2 rainfall (6–7 mm day 1), convective intensity, rainfall contributions from different morphologies, and their variations with MJO phase. Nonlinear sub-MCSs were present 70% of the time but contributed just around 20% of the total rainfall. In contrast, linear and nonlinear MCSs were present 10% of the time but contributed 20% and 50%, respectively. These distributions vary with MJO phase, with the largest sub-MCS rainfall fraction in suppressed phases (phases 5–7) and maximum MCS precipitation in active phases (phases 2 and 3). Similarly, convective–stratiform rainfall fractions also varied significantly with MJO phase, with the highest convective fractions (70%–80%) in suppressed phases and the largest stratiform fraction (40%–50%) in active phases. However, there are also discrepancies between the Revelle radar and TRMM PR.
    [Show full text]
  • 1 October-31 December 2003 Volume 18, Number 4
    Issue #25 and Volume 18, Number 4 1 October−31 December 2003 Editorial Researchers could also use the time between events to What to Do When the Pacific Is “pacific” update the various El Niño-related impacts maps for their regions, or for the entire globe. The public and media in We have recently emerged from a relatively weak El Niño different locations around the world take these maps (2002−03), and speculation and “guesstimates” by various seriously, viewing them as authoritative. These maps researchers have suggested that there would be a shift should be updated at regular intervals − say between El toward La Niña. This shift has not yet happened. For El Niño events, as researchers gather new insights with each Niño impacts researchers, this is rather boring. While the new warm event. Between El Niño, such as the present Pacific Ocean is “pacific,” it is difficult to write about time, researchers could compare societal responses to the something that seems to be boring in an exciting way. recent El Niño forecast (2002−03) with those for the 1997−98 event. Researchers have shown that together El Niño events and La Niña events occur about 55% of the time. This means that the sea surface temperatures in the equatorial Pacific are in a so-called “neutral” phase 45% of the time. That seems to be the phase of the El Niño-Southern Oscillation (ENSO) cycle at the present time. So, what are forecasters to do? What might impacts researchers do? What can the media write or discuss about El Niño or La Niña? Not much, apparently.
    [Show full text]