Atmospheres 2004 Technical Highlights: Appendix A1. Press Releases

February 10, 2004 RELEASE: 04-058


As the tropical oceans continue to heat up, following a 20-year trend, warm rains in the tropics are likely to become more frequent, according to NASA scientists.

In a study by William Lau and Huey-Tzu Jenny Wu, of NASA's Goddard Space Flight Center, Greenbelt, Md., the authors offer early proof of a long-held theory that patterns of evaporation and precipitation, known as the water cycle, may accelerate in some areas due to warming temperatures. The research appears in the current issue of Geophysical Research Letters.

The study cites satellite observations showing the rate that warm rain depletes clouds of water is substantially higher than computer models predicted. This research may help increase the accuracy of models that forecast rainfall and climate. The rate water mass in a cloud rains out is the precipitation efficiency. According to the study, when it comes to light warm rains, as sea surface temperature increases, the precipitation efficiency substantially increases.

Computer climate models that predict rainfall have underestimated the efficiency of warm rain. Compared to actual observations from NASA's Tropical Rainfall Measuring Mission (TRMM) satellite, computer models substantially underestimate the precipitation efficiency of light rain. The findings from this study will provide a range of possibilities for warm rain efficiency that will greatly increase a model's accuracy.

"We believe there is a scenario where in a warmer climate there will be more warm rain. And more warm rain will be associated with a more vigorous water cycle and extreme weather patterns," Lau said.

The process that creates warm rain begins when water droplets condense around airborne particles and clouds are created. The droplets collide, combine and grow to form raindrops. The raindrops grow large and heavy enough to fall out as warm rain. The study claims, for each degree rise in sea surface temperature, the rate a cloud loses its water to moderate-to-light warm rainfall over the tropical oceans increases by eight to 10 percent.

Cold rains are generally associated with heavy downpour. They are generated when strong updrafts carry bigger drops higher up into the atmosphere, where they freeze and grow. These drops are very large by the time they fall. Once updrafts take these large drops high enough, and freezing takes place, the process of rainfall is more dependent on the velocity of the updraft and less on sea surface temperatures. Since the process of condensation releases heat, warm rains heat the lower atmosphere. More warm rains are likely to make the air lighter and rise faster, creating updrafts producing more cold rain.

The study found warm rains account for approximately 31 percent of the total global rain amount and 72 percent of the total rain area over tropical oceans, implying warm rains play a crucial role in the overall water cycle. Light warm rains appear to occur much more frequently, and cover more area, than cold rains, even though they drop less water per shower. The total precipitation from all types of warm rains accounts for a substantial portion of the total rainfall.

In a warmer climate, it is possible there will be more warm rain and fewer clouds. If the amount of water entering into clouds stays constant and rainfall efficiency increases, then there will be less water in the clouds and more warm rains.

More study is needed to better understand the relationship between increased warm-rain precipitation efficiency and a rise in sea surface temperatures, and to determine how cold rain might be affected by an increase in warm rain and a decrease in cloud water amounts.


For more information and images related to the study on the Internet, visit:

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March 15, 2004 RELEASE: N04-090


A NASA-funded study found some climate models might be overestimating the amount of water vapor entering the atmosphere as the Earth warms. Since water vapor is the most important heat-trapping greenhouse gas in our atmosphere, some climate forecasts may be overestimating future temperature increases.

In response to human emissions of greenhouse gases, like carbon dioxide, the Earth warms, more water evaporates from the ocean, and the amount of water vapor in the atmosphere increases. Since water vapor is also a greenhouse gas, this leads to a further increase in the surface temperature. This effect is known as "positive water vapor feedback." Its existence and size have been contentiously argued for several years.

Ken Minschwaner, a physicist at the New Mexico Institute of Mining and Technology, Socorro, N.M., and Andrew Dessler, a researcher with the University of Maryland, College Park, and NASA's Goddard Space Flight Center, Greenbelt, Md, did the study. It is in the March 15 issue of the American Meteorological Society's Journal of Climate. The researchers used data on water vapor in the upper troposphere (10-14 km or 6-9 miles altitude) from NASA's Upper Atmosphere Research Satellite (UARS).

Their work verified water vapor is increasing in the atmosphere as the surface warms. They found the increases in water vapor were not as high as many climate-forecasting computer models have assumed. "Our study confirms the existence of a positive water vapor feedback in the atmosphere, but it may be weaker than we expected," Minschwaner said.

"One of the responsibilities of science is making good predictions of the future climate, because that's what policy makers use to make their decisions," Dessler said. "This study is another incremental step toward improving those climate predictions," he added.

According to Dessler, the size of the positive water vapor feedback is a key debate within climate science circles. Some climate scientists have claimed atmospheric water vapor will not increase in response to global warming, and may even decrease. General circulation models, the primary tool scientists use to predict the future of our climate, forecast the atmosphere will experience a significant increase in water vapor.

NASA's UARS satellite was used to measure water vapor on a global scale and with unprecedented accuracy in the upper troposphere. Humidity levels in this part of the atmosphere, especially in the tropics, are important for global climate, because this is where the water vapor has the strongest impact as a greenhouse gas.

UARS recorded both specific and relative humidity in the upper troposphere. Specific humidity refers to the actual amount of water vapor in the air. Relative humidity relates to the saturation point, the amount of water vapor in the air divided by the maximum amount of water the air is capable of holding at a given temperature. As air temperatures rise, warm air can hold more water, and the saturation point of the air also increases.

In most computer models relative humidity tends to remain fixed at current levels. Models that include water vapor feedback with constant relative humidity predict the Earth's surface will warm nearly twice as much over the next 100 years as models that contain no water vapor feedback.

Using the UARS data to actually quantify both specific humidity and relative humidity, the researchers found, while water vapor does increase with temperature in the upper troposphere, the feedback effect is not as strong as models have predicted. "The increases in water vapor with warmer temperatures are not large enough to maintain a constant relative humidity," Minschwaner said. These new findings will be useful for testing and improving global climate models.

NASA's Earth Science Enterprise is dedicated to understanding the Earth as an integrated system and applying Earth system science to improve prediction of climate, weather and natural hazards using the unique vantage point of space. NASA plans to launch the Aura satellite in June 2004. Along with the Terra and Aqua satellites already in operation, Aura will monitor changes in Earth's atmosphere.



April 20, 2004 RELEASE: 04-121


Like thermometers in space satellites are taking the temperature of the Earth's surface or skin. According to scientists, the satellite data confirms the Earth has had an increasing "fever" for decades.

For the first time, satellites have been used to develop an 18-year record (1981-1998) of global land surface temperatures. The record provides additional proof Earth's snow-free land surfaces have, on average, warmed during this time period, according to a NASA study appearing in the March issue of the Bulletin of the American Meteorological Society. The satellite record is more detailed and comprehensive than previously available ground measurements. The satellite data will be necessary to improve climate analyses and computer modeling.

Menglin Jin, the lead author, is a visiting scientist at NASA's Goddard Space Flight Center, Greenbelt, Md., and a researcher with the University of Maryland, College Park, Md. Jin commented until now global land surface temperatures used in climate change studies were derived from thousands of on-the-ground World Meteorological Organization (WMO) stations located around the world, a relatively sparse set of readings given Earth's size. These stations actually measure surface air temperature at two to three meters above land, instead of skin temperatures. The satellite skin temperature dataset is a good complement to the traditional ways of measuring temperatures.

A long-term skin temperature data set will be essential to illustrate global as well as regional climate variations. Together with other satellite measurements, such as land cover, cloud, precipitation, and sea surface temperature measurements, researchers can further study the mechanisms responsible for land surface warming.

Furthermore, satellite skin temperatures have global coverage at high resolutions, and are not limited by political boundaries. The study uses Advanced Very High Resolution Radiometer Land Pathfinder data, jointly created by NASA and the National Oceanic and Atmospheric Administration (NOAA) through NASA's Earth Observing System Program Office. It also uses recently available NASA Moderate Resolution Imaging Spectroradiometer skin temperature measurements, as well as NOAA TIROS Operational Vertical Sounder (TOVS) data for validation purposes. All these data are archived at NASA's Distributed Active Archive Center.

Inter-annually, the 18-year Pathfinder data in this study showed global average temperature increases of 0.43 Celsius (C) (0.77 Fahrenheit (F)) per decade. By comparison, ground station data (2 meter surface air temperatures) showed a rise of 0.34 C (0.61 F) per decade, and a National Center for Environmental Prediction reanalysis of land surface skin temperature showed a similar trend of increasing temperatures, in this case 0.28 C (0.5 F) per decade. Skin temperatures from TOVS also prove an increasing trend in global land surfaces. Regional trends show more variations.

"Although an increasing trend has been observed from the global average, the regional changes can be very different," Jin said. "While many regions were warming, central continental regions in North America and Asia were actually cooling."

One issue with the dataset is that it cannot detect surface temperatures over snow. In winter, most of the land areas in the mid to upper latitudes of the Northern Hemisphere are covered by snow. Of Earth's land area, 90 percent of it is snow free in July, compared to only 65 percent in January. For this reason, the study only focused on snow free areas. Still, in mountainous areas that are hard to monitor, like Tibet, satellites can detect the extent of snow coverage and its variations.

The satellite dataset allows researchers to also look at daily trends on global and regional scales. The largest daily variation was above 35.0 C (63 F) at tropical and sub-tropical desert areas for a July 1988 sample, with decreasing daily ranges towards the poles, in general. Daily changes were also closely related to vegetation cover. The daily skin temperature range showed a decreasing global mean trend over the 18-year period, resulting from greater temperature increases at night compared to daytime.

Things like clouds, volcanic eruptions, and other factors gave false readings of land temperatures, but scientists factored those out to make the skin temperature data more accurate. Scientists are considering extending this 18-year satellite-derived skin temperature record up to 2003. The mission of NASA's Earth Science Enterprise is to develop a scientific understanding of the Earth system and its response to natural or human-induced changes to enable improved prediction capability for climate, weather, and natural hazards. NASA funded the study.

For more information and images about the research, visit:

April 28, 2004 RELEASE: 04-110


NASA is providing new technology and satellite data to help forecasters at the National Oceanic and Atmospheric Administration (NOAA) create the best possible forecasts of severe springtime weather.

New NASA data gathered from satellites, a lightning ground-tracking network and unmanned vehicles that fly into storms are some of the many tools used by NOAA, the federal agency charged with issuing weather forecasts. This data will help make the severe weather season safer for everyone.

"It's an evolutionary process and partnership between NOAA and NASA," said Bill Patzert, oceanographer at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "NOAA is the ultimate operational meteorological agency in the world, and NASA is developing state-of-the-art operational and fundamental research to make it better than ever. Together we're looking to the future to provide better and better service to the American public," he said.

NOAA's National Weather Service (NWS) is responsible for monitoring and forecasting severe weather events. They issue watches and warnings for tornadoes, flash floods, non-precipitation events (such as high wind warnings), severe thunderstorms, and flooding, as well as daily weather forecasts. They reach the public with these warnings mainly through NOAA weather radio and the Internet.

NASA uses data from its Earth-observing satellites and models to characterize and understand the way atmosphere, oceans and land interact. "Adding NASA satellite data and model output to NOAA forecasts could lead to more confident seven-day severe local storm forecasts, better prediction of thunderstorm occurrence by three hours, and an increase in tornado warning lead times by 18 minutes," said Dr. Marshall Shepherd, research meteorologist at NASA's Goddard Space Flight Center, Greenbelt, Md.

NASA satellite data that enhances NOAA's weather model forecasts include surface wind data from QuikScat and rainfall data from the Tropical Rainfall Measuring Mission satellite. Launching in June 2004, NASA's Aura satellite will provide temperature and moisture information. That data will provide a clearer atmospheric picture, and it will improve forecast model prediction capabilities.

Better understanding of jet steam locations, temperature, humidity fields and other atmospheric states are critical in assessing the potential for severe weather. Balloon observations taken twice daily at approximately 180 locations in the United States are the main source of this type of information. New NASA satellite observations can fill in the missing data spaces around the United States and surrounding oceans. The NASA-NOAA Joint Center for Satellite Data Assimilation was formed in 2002 to accelerate the use of satellite data within global-scale weather forecast models operated by NOAA.

NASA's Short-term Prediction Research and Transition (SPoRT) Center at NASA's Marshall Space Flight Center, Ala., is working closely with NWS forecasters in the southern United States to improve severe weather forecasting. NASA scientists are using data obtained from the ground-based Lightning Mapping Array in northern Alabama to better understand the relationship between lightning flash rates and tornado-producing thunderstorms.

The SPoRT Center provides lightning data to surrounding NWS forecast offices in real time for use in severe weather warning decision-making. "There has been one event where the NASA lightning data prompted NWS forecasters in the Huntsville, Alabama office to issue a tornado warning on a strong convective cell earlier than they would have otherwise," said Dr. William Lapenta, SPoRT Center research meteorologist. A weak tornado occurred after the warning was issued. Research is also underway to improve flooding forecasts by incorporating new satellite data from the NASA Atmospheric InfraRed Sounder instrument into NWS weather forecast models on a regional scale.

In February, NASA's Langley Research Center, Hampton, Va., flight-tested the Global Positioning System Reflectometer on an unmanned aerial vehicle to collect data in severe weather situations. In 2002, NASA, universities and industries conducted the Altus Cumulus Electrification Study in Florida, the first time a remotely piloted aircraft was used to conduct lightning research.


For more information about severe weather on the Internet, visit: and

May 3, 2004 RELEASE: 04-147














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May 4, 2004 RELEASE: 04-148





NASA recipients and their research proposals:






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May 26, 2004 RELEASE: 04-168













June 9, 2004 RELEASE: 04-183



Researchers analyzed multiple years of data from NASA's Tropical Rainfall Measuring Mission (TRMM). They also used data from the Department of Defense Special Sensor Microwave Imager and the National Oceanic and Atmospheric Administration's Geostationary Operational Environmental Satellites.

The study is in a recent American Meteorological Society Journal of Climate. Lead authors, Andrew Negri and Robert Adler, are research meteorologists at NASA's Goddard Space Flight Center (GSFC), Greenbelt, Md. Other authors include Liming Xu, formerly with the University of Arizona, Tucson, and Jason Surratt, North Carolina State University, Raleigh.

"In deforested areas, the land heats up faster and reaches a higher temperature, leading to localized upward motions that enhance the formation of clouds and ultimately produce more rainfall," Negri said.

The researchers caution the rainfall increases were most pronounced in August, during the transition from dry to wet seasons. In this transition period, the effects of land cover, such as evaporation, are not overwhelmed by large-scale weather disturbances that are common during the rest of the year. While the study, based on satellite data analysis, focused on climate changes in the deforested areas, large increases in cloud cover and rainfall were also observed in the naturally un-forested savanna region and surrounding the urban area of Port Velho, Brazil, particularly in August and September.

Recent studies by Dr. Marshall Shepherd cited similar findings, including an average rain-rate increase of 28 percent downwind of urban areas and associated changes in the daily timing of cloud formation and precipitation. He is also a research meteorologist at GSFC.

This research confirmed the Amazon savanna region experienced a shift in the onset of cloudiness and rainfall toward the morning hours. The shift was likely initiated by the contrast in surface heating across the deforested and savanna region.

The varied heights of plants and trees in the region change the aerodynamics of the atmosphere, creating more circulation and rising air. When the rising air reaches the dew point in the cooler, upper atmosphere, it condenses into water droplets and forms clouds.

Negri acknowledged other factors are involved. The savanna in this study is approximately 100 kilometers (62 miles) wide, the perfect size to influence precipitation, such as rain showers and thunderstorms. Earlier studies hypothesized certain land surfaces, such as bands of vegetation 50 to 100 kilometers (31-62 miles) wide in semiarid regions, could result in enhanced precipitation.

This research is in agreement with the recent and sophisticated computer models developed by the Massachusetts Institute of Technology. The models concluded small-scale circulations, including the mixing and rising of air induced by local land surfaces, could enhance cloudiness and rainfall. Many earlier studies that relied on models developed in the 1990s or earlier concluded widespread deforestation of the Amazon Basin would lead to decreased rainfall.

"The effects here are rather subtle and appear to be limited to the dry season. The overall effect of this deforestation on annual and daily rainfall cycles is probably small and requires more study," Negri said. Future research will use numerical models for investigating the linkage between deforested land surface and the cloud-precipitation components of the water cycle.


For more information and images about this research on the Internet, visit:


June 10, 2004 RELEASE: 04-187


NASA and University of Maryland scientists have found the African monsoon consists of two distinct seasons.

The first season is in the late spring and early summer. The rain is concentrated on the West African Coast near the Gulf of Guinea, five degrees north of the equator. This season appears strongly influenced by sea surface temperatures off the coast of West Africa.

The second season arrives later in summer in July at around 10 degrees north of the equator. Atmospheric waves moving westward over the Atlantic Ocean appear to play a major role in this summer season monsoon rainfall, according to the research using NASA's Tropical Rainfall Measuring Mission (TRMM) satellite. These waves, called African Easterly Waves, are evident in the rain patterns.

The research results appeared in a recent issue of Journal of Geophysical Research and in a paper in the Journal of Climate. Additional research will explore connections between African Easterly Waves and hurricane activity.

"Most people agree the later season is determined by the atmosphere, but we found the early spring monsoon is determined by being close to the ocean," said Guojun Gu, lead author of the study. Gu is a researcher at NASA's Goddard Space Flight Center (GSFC), Greenbelt, Md., and the Goddard Earth Sciences and Technology Center at the University of Maryland, Baltimore County. "Also, if the spring rain is weak, then the summer monsoon is strong, and vice versa," Gu said.

A study from 1998 to 2002 of daily rainfall from the TRMM satellite, combined with information from other satellites, defined the evolution of the African monsoon. This very high-quality dataset of rainfall rates helped determine the distinct northward "jump" in the monsoon from the early summer season to the later summer episode.

In the May to June season, large differences in sea surface temperatures between coastal waters and water further out to sea lead to increased rainfall. When coastal waters are warm and equatorial waters are colder, rainfall is stronger along the coastline. The July monsoon is related to the easterly waves. These waves carry a great deal of moisture and provide the seasonal monsoon rain before moving off the west coast of Africa.

Previous research suggests the African Easterly Waves may kick off small circulations that develop into hurricanes over the North Atlantic Ocean. Up to 80 percent of the major hurricanes that impact the eastern United States may originate with these waves. "You can track a hurricane backward in time to waves coming off the African coast and all the way to the mainland of Africa," said Robert Adler, a co-author and researcher at GSFC.

The African Easterly Waves occur only during summer months, from May through October. While the waves vary greatly in strength from year to year, their numbers stay consistently at about 60 to 70 per year. These waves consist of low-pressure systems that pass every three to four days, with a wavelength of about 2000 to 2500 kilometers. More study is needed to better understand how variations in the waves impact hurricanes.

The researchers also found the nature of these waves shifts at about the 15-degree north line. The waves that pass south of this line carry moisture and create convection that lead to rain clouds. These southern waves play a role in both the later summer monsoons and the genesis of hurricanes. But waves that pass north of the 15-degree line carry hot dry air from the Sahara. These waves may carry tons of dust as they move west with trade winds. In about a week they can carry dust all the way to the Gulf of Mexico and Florida.

The mission of NASA's Earth Science Enterprise is to develop a scientific understanding of the Earth System and its response to natural or human-induced changes to enable improved prediction capability for climate, weather, and natural hazards.

For more information about this research on the Internet, visit:

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July 15, 2004 RELEASE: 04-217


Aura, a mission dedicated to the health of the Earth's atmosphere, successfully launched today at 6:01:59 a.m. EDT (3:01:59 a.m. PDT) from Vandenberg Air Force Base, Calif., aboard a Boeing Delta II rocket. Spacecraft separation occurred at 7:06 a.m. EDT (4:06 a.m. PDT), inserting Aura into a 438-mile (705-kilometer) orbit.


"This moment marks a tremendous achievement for the NASA family and our international partners. We look forward to the Aura satellite offering us historic insight into the tough issues of global air quality, ozone recovery and climate change," said NASA Associate Administrator for Earth Science Dr. Ghassem Asrar. "This mission advances NASA's exploration of Earth and will also better our understanding of our neighbors in the planetary system. Aura joins its siblings, Terra, Aqua and 10 more research satellites developed and launched by NASA during the past decade, to study our home planet," he added.

Aura will help answer three key scientific questions: Is the Earth's protective ozone layer recovering? What are the processes controlling air quality? How is the Earth's climate changing? NASA expects early scientific data from Aura within 30-90 days.

Aura also will help scientists understand how the composition of the atmosphere affects and responds to Earth's changing climate. The results from this mission will help scientists better understand the processes that connect local and global air quality.

Each of Aura's four instruments is designed to survey different aspects of Earth's atmosphere. Aura will survey the atmosphere from the troposphere, where mankind lives, through the stratosphere, where the ozone layer resides and protects life on Earth.

With the launch of Aura, the first series of NASA's Earth Observing System satellites is complete. The other satellites are Terra, which monitors land, and Aqua, which observes Earth's water cycle.


HIRDLS was built by the United Kingdom and the United States. OMI was built by the Netherlands and Finland in collaboration with NASA. NASA's Jet Propulsion Laboratory in Pasadena, Calif., constructed TES and MLS. NASA's Goddard Space Flight Center, Greenbelt, Md., manages the Aura mission.

"Many people have worked very hard to reach this point and the entire team is very excited," said Aura Project Manager Rick Pickering of Goddard.


For Aura information and images on the Internet, visit: and

July 22, 2004 RELEASE: 04-235












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July 29, 2004 RELEASE: 04-247


Some people think cities and nature don't mix, but a new NASA-funded study finds that concrete jungles create warmer conditions that cause plants to stay green longer each year, compared to surrounding rural areas.

Urban areas with high concentrations of buildings, roads and other artificial surfaces retain heat, creating urban heat islands. Satellite data reveal that urban heat islands increase surface temperatures compared to rural surroundings.

Using information from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) instrument on the Terra satellite, Boston University, Boston, researchers discovered that city climates have a noticeable influence on plant growing seasons up to 10 kilometers (6 miles) away from a city's edges. Growing seasons in 70 cities in eastern North America were about 15 days longer in urban areas compared to rural areas outside of a city's influence.

"If you live in a rural area and drive regularly into the city, and if you pay attention to vegetation, you will see a difference in the growing seasons in early spring and late autumn," said Xiaoyang Zhang, the study's lead author and a researcher at Boston University. The study appeared in a recent issue of the American Geophysical Union's Geophysical Research Letters journal.

Zhang added that urban heat islands provide a very good model to assess the effects of global warming on plant growing seasons and ecosystems. As temperatures warm due to climate change, growing seasons will likely change as well. Zhang and colleagues found that for every 1 degree Celsius (C) or 1.8 Fahrenheit (F) that temperatures rose on average during the early springtime, vegetation bloomed 3 days earlier.

Springtime land surface temperatures in eastern North American cities were on average 2.3 C (4.1 F) warmer than surrounding rural areas, according to the study. In late autumn to winter, the city temperatures were 1.5°C (2.7°F) higher than the surrounding areas. These higher urban temperatures caused plants to start greening-up on average seven days earlier in spring. Similarly, in urban heat island areas, the growing season lasted eight days longer in the fall than the rural areas.

The researchers used MODIS surface reflectance data to measure seasonal changes in plant growth for the entire year of 2001. By accounting for angles of views from the satellite, varying sunlight, land surface temperatures, cloud cover, and the presence of snow, the scientists were able to detect daily variations in the green color of plants.

The researchers classified urban areas using MODIS data from October 2000 to October 2001, as well as Defense Meteorological Satellite Program's (DMSP) nighttime lights imagery and population density data. Only eastern North American cities with urban areas larger than 10 square kilometers (4 square miles) were included in the study.

The researchers found that the effect urban heat islands have on plants' growing seasons is exponentially weaker the further away from the city one travels. Significant effects were seen up to 10 kilometers (6 miles) from city lines. In other words, the impact of urban climates on ecosystems extended out 2.4 times the size of a city itself.

"Warming from global climate change will definitely impact ecosystems," Zhang said. "Thus, urban areas provide us with some measures of how changes in temperature might affect vegetation," he added.




September 2, 2004 NOTE TO EDITORS: N04-135


Weather experts will explain how NASA satellite data contributes to our understanding of hurricanes during a telephone media opportunity Tuesday at 1:30 p.m. EDT.

Research meteorologists, Dr. J. Marshall Shepherd (NASA) and Dr. Jeffrey Halverson (University of Maryland), will discuss the latest in hurricane science. NASA's research aids hurricane forecasting and tracking around the globe during storm seasons.

Sept. 20, 2004 RELEASE: 04-305


Women in Aerospace (WIA) will honor three NASA women for their professional aerospace accomplishments during the organization's 19th annual awards program tomorrow in Washington.

Estelle Condon, Associate Center Director for Astrobiology and Space Programs at NASA's Ames Research Center, Moffett Field, Calif., will receive the Lifetime Achievement Award.

Dr. Ann Thompson, a research scientist in atmospheric chemistry at NASA's Goddard Space Flight Center, Greenbelt, Md., will receive the International Achievement Award.

Dr. Rebecca A. MacKay, Science Advisor to the Materials Division Chief at NASA's Glenn Research Center, Cleveland, will receive the Outstanding Achievement Award.

"Congratulations to these extraordinary women, who embody the very qualities NASA needs to achieve the Vision for Space Exploration," said NASA Administrator Sean O'Keefe. "In addition to their own significant accomplishments, they have consistently worked as role models and mentors to enhance the transfer of knowledge to the next generation of explorers. I salute them for their accomplishments and applaud WIA for recognizing them."

WIA will present the awards during a public reception at the Rayburn House Office Building Foyer from 6 to 8 p.m. WIA will present three other awards at the reception, the Outstanding Leadership Award, the Aerospace Awareness Award, and the Aerospace Educator Award, to women who work in the private sector. WIA is a non-profit organization dedicated to expanding women's opportunities for leadership and increasing their visibility in the aerospace community.

Nov. 8, 2004 RELEASE: 04-369


NASA scientists recently found the El Niño Southern Oscillation (ENSO) is the main driver of the change in rain patterns all around the world.


Researchers Ziad Haddad and Jonathan Meagher of NASA's Jet Propulsion Laboratory, Pasadena, Calif., Robert Adler and Eric Smith of NASA's Goddard Space Flight Center, Greenbelt, Md., used TRMM data to identify areas where the year-to-year change in rainfall between 1998 and 2003 was greatest.

By studying the rain patterns in these areas over the past 50 years, with rain gauge data prior to 1998, they established the main component of this change in global rainfall is directly correlated with the El Niño Southern Oscillation. The study appeared in a recent issue of the Journal of Geophysical Research-Atmospheres.

Haddad and his colleagues compared local changes in worldwide rainfall. For years, scientists have known El Niño drastically modifies rainfall patterns in many regions. For example, Indonesia and the Northeastern Amazon basin consistently suffer droughts during El Niño and excessive rains during La Niña. The Southeastern United States and California are typically wetter than usual during El Niño and drier than usual during La Niña.

Scientists also have known several regions with abundant rain are not influenced by the El-Niño/La-Niña changes, including the Bay of Bengal and the vast expanse of the Western Pacific Ocean between the Marshall Islands, Micronesia and the Marianas.

Until the launch of TRMM in 1997, it was impossible to accurately measure change in tropical rainfall patterns, because no instruments were available to record global rainfall. TRMM uses microwave technology to probe through clouds and estimate how much rainfall they are producing. The TRMM data are invaluable over areas where there are no rain gauges, such as the open ocean.

Using TRMM's measurements, the researchers were able to condense the year-to-year change in rainfall patterns into a single rain-change index. The index is a color-coded map that shows areas of rainfall around the world that are influenced somewhat to greatly, during an ENSO event.

Rainfall data from land and island stations were used to extend this index back in time and to compare it with the ENSO sea-surface temperature and atmospheric pressure. The results showed a strong relationship between the rainfall patterns and ENSO. "The fact that the rain-change index, which comes directly from global measurements, tracks the ENSO indices from the 1950s to the present confirms that El Niño is the principal driver of global year-to-year rainfall change," Haddad said.

NASA plans the Global Precipitation Measurement mission (GPM), a future multi-national multi-satellite mission to expand the scope of TRMM. GPM will focus on producing three-dimensional maps of rain around the world every three hours.

TRMM is the first space-based rain gauge that uses microwaves to see how much precipitation falls from clouds around the tropics. The TRMM satellite's precipitation radar acts like a highly sensitive microwave camera. It is capable of probing clouds to reveal their vertical structure and precipitation they produce. It has enabled scientists to measure rainfall over the oceans and landmasses with unprecedented accuracy.

December 14, 2004 RELEASE: 04-391


NASA scientists announced the agency's Aura spacecraft is providing the first daily, direct global measurements of low-level ozone and many other pollutants affecting air quality.

For the first time, Aura will help scientists monitor global pollution production and transport with unprecedented spatial resolution. Aura's measurements offer new insights into how climate changes influence the recovery of the Earth's protective stratospheric ozone layer.

"Data from NASA missions like Aura are a valuable national asset," said Aura Program Scientist Phil DeCola of NASA Headquarters, Washington. "Clean air is a vital need, and air quality is not merely a local issue. Pollutants do not respect state or national boundaries. They can degrade air quality far from their sources. Aura's view from space enables us to understand the long-range transport of pollutants," he added.

"Aura's early results are nothing short of astounding; measurements like these will help us better understand how the ozone hole will react to future stratospheric cooling, which is expected as carbon dioxide levels continue to rise," said Aura Project Scientist Mark Schoeberl of NASA's Goddard Space Flight Center, Greenbelt, Md.

Aura's instruments study tropospheric chemistry and will provide daily, global monitoring of air pollution. The complexity of pollution transport makes it difficult to quantify how much industry and cars contribute to poor local air quality. Also, the presence of stratospheric ozone sandwiched between the satellite and the troposphere makes seeing tropospheric ozone very difficult. Aura's Tropospheric Emission Spectrometer (TES) uses new technology to see through the stratospheric ozone layer, to measure tropospheric ozone.

Aura also provides new insights into the physical and chemical processes that influence the health of the stratospheric ozone layer and climate. It's producing the most complete suite of chemical measurements ever available to understand the ozone layer and its recovery.

Data will include the first measurements of chemically reactive hydrogen-containing species involved in ozone destruction. The satellite also will provide the first simultaneous measurements of key forms of chlorine and bromine, also important for ozone destruction. Aura measures the upper-tropospheric water-vapor abundance, a key component in the radiation budget, needed to understand climate change.

Launched July 15, 2004, Aura is the third and final major Earth Observing System satellite. Aura's view of the atmosphere and its chemistry will complement the global data already being collected by NASA's other Earth Observing System satellites. These projects are Terra, primarily focused on land, and Aqua, which comprehensively observes Earth's water cycle. Collectively, these satellites allow scientists to study the complexities of how land, water and our atmosphere work as a system.

Aura carries four instruments: Ozone Monitoring Instrument (OMI), Microwave Limb Sounder (MLS), High Resolution Dynamics Limb Sounder (HIRDLS) and the Tropospheric Emission Spectrometer (TES). OMI was built by the Netherlands and Finland in collaboration with NASA. HIRDLS was built by the United Kingdom and the United States.

Dec. 14, 2004 RELEASE: 04-398








Selected investigations and principal investigators:







