News Archive

Latest Drought Forecast Brings Mix of Good and Bad
For drought-stricken areas of the United States, there is both good and bad news. The good news is La Niņa, the weather phenomenon responsible for bringing drought conditions to some parts of the nation for the past two years, is expected to continue diminishing for the next several months. The bad news is above-normal temperatures, which speed up the evaporation of precipitation and soil moisture, are forecast to affect drought-weary states for the rest of the spring into summer. The forecast, released May 16 by NOAA's National Weather Service, is part of the National Drought Policy Commission's report on the impact of the drought in America.

global change research
Soot Shown to Reduce Tropical Cloudiness
Aerosols are generally thought to produce climate cooling by increasing Earth's albedo, either by increasing the size of cloud droplets or by acting as condensation nuclei that can increase the amount of water in clouds or the extent of cloud cover. All of these effects reflect more solar energy back into space. A group of researchers, headed by A. S. Ackerman of NASA, have now shown that high aerosol concentrations can also decrease albedo and promote warming. The daytime coverage of trade-cumulus clouds can be reduced by more than half by aerosol pollution, an effect that could influence atmospheric circulation by weakening deep convection in the intertropical convergence zone.

The entire article is available on-line for subscribers to Science Online.

New Fact Sheet Describes Significant Floods of the 20th Century
When there is a flood, the U.S. Geological Survey (USGS) is usually there to measure it. According to a USGS press release, the USGS has measured floods and supplied streamflow data to the nation for more than 110 years and now has released a new fact sheet listing the most significant floods of the 20th century. During the 20th century, floods were the number-one disaster in the United States in terms of lives lost and property damage, according to the new fact sheet by the USGS. Flooding has caused the deaths of more than 10,000 people since 1900. Property damage from flooding now totals over $1 billion each year in the United States. The fact sheet discusses 32 significant floods that occurred during the 20th century. The floods were determined to be significant based on a combination of factors including lives lost, and total damage and are broken down into six types of floods: large regional flooding, flash floods, storm surge floods, ice-jam floods, dam and levee failure and mudflow floods.

USGS Fact Sheet 024-00 is available in HTML and PDF formats.

global change research
UMass Researchers Find El Niño-Like Climate Patterns Occurred in New England During the Ice Age
The New England region underwent El Niņo-like climate changes during the Ice Age, reports a University of Massachusetts Amherst press release. University of Massachusetts geoscientist Julie Brigham-Grette led the research, along with former UMass graduate student Tammy Rittenour (now a doctoral candidate at the University of Nebraska), and environmental scientist Michael Mann, now at the University of Virginia. The findings are detailed in the May 12 issue of Science. The project was funded by the National Science Foundation, National Geographic Society, and the University of Massachusetts. The report offers scientists a clearer understanding of El Niņo's persistence at a time when climate conditions were fundamentally different from the climate conditions of today, according to the team. "El Niņo-like climate change can happen under all sorts of conditions, even when the Northern Hemisphere is covered with large ice sheets," said Brigham-Grette. "It's not just a warm-weather phenomenon. Knowing this will help scientists in determining what drives El Niņos."

The entire article is available on-line for subscribers to Science Online.

global change research
Scientists Say Adios to La Niña
La Niña, the large area of cold water in the Pacific Ocean widely blamed for last summer's drought and often related to an increase in the number of hurricanes that make landfall, appears to be on its last legs. According to a NASA press release, the latest spacecraft and ocean buoy observations show that the La Niña has disappeared entirely in the eastern Pacific Ocean and is rapidly disappearing over the rest of the Pacific. "The current lack of cold water support below the surface means that this La Niña will have a difficult time sustaining itself for much longer", according to David Adamec, a research oceanographer at Goddard Space Flight Center in Greenbelt, Md. "As expected, the La Niña reached a maximum in intensity during January 2000 and has been waning ever since." The spacecraft data have also shown that since March, La Niña's cold surface water is being replaced by water that is now 4 degrees Fahrenheit warmer than normal off the coast of South America. The current longevity of this "warm water patch" is now beginning to affect the atmosphere by weakening the trade winds there. These weakened winds are also very unfavorable for the persistence of La Niña conditions.

global change data
NASA Spacecraft Data Improves Tropical Forecasts
A microwave imager onboard a NASA spacecraft can help improve the forecasts of hurricanes, severe storms, and monitor long-term climate by seeing through clouds, reports a recent NASA press release. The Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) represents the first microwave spacecraft sensor capable of accurately measuring sea-surface temperatures through clouds. These findings were reported in the May 5th issue of Science, by Frank Wentz and colleagues at Remote Sensing Systems, Santa Rosa, CA, who also are TRMM Science Team members. Science team members have found that data from the TRMM Microwave Imaging (TMI) sensor onboard the spacecraft has great potential to increase the accuracy of tropical storm and climate forecasts. Microwave radiation penetrates clouds with little loss of signal thereby providing an uninterrupted view of the ocean surface whereas much of the infrared radiation, typically used for measuring sea-surface temperatures from satellites, are blocked by cloud cover. "The microwave imager can give consistent readings of sea-surface temperatures even through clouds," said Wentz, director of Remote Sensing Systems. "To date we've been limited by infrared sensors. Having the complete picture of ocean surface temperatures should greatly improve numerical models being run by the National Weather Service."

The entire article is available on-line for subscribers to Science Online. Additional information is available on the TRMM Web Site and Remote Sensing Systems Home Page.

For the first time, daily river forecasts and flood stage information from the nation's largest river basins are now available on a single Internet site thanks to NOAA's National Weather Service. The Weather Service's new River Watch home page is a service even more crucial as various parts of the nation are gripped by drought. "This new 'one stop' Web site provides almost instant access to river data within the Illinois, Mississippi, Missouri, and Ohio River Basins," said retired Air Force Brig. Gen. Jack Kelly, National Weather Service director. "The new site combines river information from more than a dozen weather service offices and makes them available to anyone with access to the Internet."

data policies
NASA Earth Science Enterprise Data Pricing Policy to be Implemented within EOSDIS
NASA will start recoving "full marginal costs" for distribution of data products
NASA's Earth Science Enterprise (ESE) has decided to proceed with implementing a cost for distribution of products at the level of recovering the full marginal cost, consistent with Circular A-130. By instituting a marginal cost charging policy, ESE is creating a means of remaining responsive to new and real increasing demand without incurring further burden on the US taxpayer. NASA has officially submitted language for its 2001 authorization bill to enable it to retain receipts from recovering user charges. For more information, see the ESE Data Pricing Policy Notice.

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