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The U.S. Geological Survey (USGS) is teaming up with NASA to extend the useful life of the Earth Observing 1 (EO-1) technology demonstration satellite. NASA officially completed the EO-1 mission in November 2001, but the two agencies, already management partners for the Landsat satellite program, have agreed to work together to extend EO-1 operations through February 2002 and then continue on a month-by-month basis. EO-1 archive data and new acquisitions from two of its three prototype sensors, the Advanced Land Imager and Hyperion, can now be ordered from the USGS, with the first products slated to be shipped in early February. Extending the EO-1 mission enables both agencies to sustain their research and development efforts while providing opportunities for the broader research community to obtain sample data over specified sites. USGS and NASA scientists believe both Landsat-like and "hyperspectral" data types from EO-1 could prove to be valuable in global land cover studies, ecosystem monitoring, mineral and petroleum prospecting, and agricultural crop discrimination and assessment, among other potential applications. No restrictions will be placed on users obtaining EO-1 products from the USGS.

A new NASA-funded study shows that the rate of growth of greenhouse gas emissions has slowed since its peak in 1980, due in part to international cooperation that led to reduced chlorofluorocarbon use, slower growth of methane, and a steady rate of carbon dioxide emissions. Researchers have shown that global warming in recent decades has probably been caused by carbon dioxide (CO₂), and other greenhouse gases including chlorofluorocarbons (CFCs), methane, tropospheric ozone, and black carbon (soot) particles. Overall, growth of emissions has slowed over the past 20 years, with the CFC phase-out being the most important factor, according to the study.

"The decrease is due in large part to cooperative international actions of the Montreal Protocol for the phase-out of ozone depleting gases," said Dr. James Hansen of NASA's Goddard Institute for Space Studies, New York. "But it is also due in part to slower growth of methane and carbon dioxide, for reasons that aren't well understood and need more study." The findings appeared in the 18 December issue of the Proceedings of the National Academy of Sciences. Hansen co-authored the paper with Makiko Sato of Columbia University, New York.

NOAA's Climate Prediction Center officially announced on 10 January that warming is being observed over the Tropical Pacific, which could lead to an El Niņo by early Spring. The U.S. is not expected to see its potential impacts until late summer, through the fall and into next winter. NOAA cautions the public that it is too early to predict the magnitude of the potential 2002 El Niņo, or how long it would last. "The magnitude of an El Niņo determines the severity of its impacts," said Vernon Kousky, NOAA climate specialist. "At this point, it is too early to predict if this El Niņo might develop along the same lines as the 1997-98 episode, or be weaker," said Kousky.

The announcement is strongly supported by enhanced cloudiness and precipitation occurring over the equatorial central Pacific for the first time since the 1997-98 El Niņo episode. Indications for a warm episode, or El Niņo, in the Tropical Pacific was first noted in August 2001. "Considering the observed oceanic and atmospheric circulation patterns and their recent evolution, it seems most likely that warm-episode conditions will develop in the tropical Pacific over the next 3-6 months," said Kousky.

global change research
Climate Change May Bring More Winter Floods, and a Drier Growing Season in California
A new study finds that climate warming over the next century will bring potential flooding in winter, as a result of increased streamflow throughout California. The study also finds less water would be available during the summer months. Norman Miller and Kathy Bashford of Lawrence Berkeley National Laboratory (LBNL), and Eric Strem of the National Weather Service's (NWS) California-Nevada River Forecast Center looked at two climate change scenarios projected out to the year 2100. Based on these scenarios, they determined how the smallest to largest expected changes in regional temperature and precipitation would affect streamflow throughout California.

The two scenarios, both warmer and wetter than present day, were based on findings from the 2001 Intergovernmental Panel on Climate Change (IPCC) report. The report predicted temperature increases by as much as 9° Fahrenheit (F) with potential localized fluctuations in precipitation throughout the 21st century. The researchers evaluated climate change projections for three time periods; 2010-2039; 2050-2079; and 2080-2100. The projections included increases in temperature between 2.7°F (or 1.5° Celsius (C)) to 9.0°F (5.0°C) and changes in precipitation from 0.0 to 30.0 percent.

global change research
Scientists Describe Century of Human Impact on Global Surface Temperature
Human activity has affected Earth's surface temperature during the last 130 years, according to a study published this month by the Journal of Geophysical Research. Dr. Robert K. Kaufmann of Boston University's Center for Energy and Environmental Studies and Dr. David I. Stern of the Australian National University's Centre for Resource and Environmental Study analyzed historical data for greenhouse gas concentrations, human sulfur emissions, and variations in solar activity between 1865 and 1990. The greenhouse gases studied included carbon dioxide, methane, nitrous oxide, and chloroflurocarbons 11 and 12. Using the statistical technique of cointegration, the scientists compared these factors over time with global surface temperature in both the northern and southern hemispheres. This is the first study to make a statistically meaningful link between human activity and temperature, independent of climate models, Kaufmann notes. They found that the impact of human activity has been different in the two hemispheres. In the north, the warming effect of greenhouse gases was almost exactly offset by the cooling effect of sulfur emissions, making the temperature effects difficult to observe. In the southern hemisphere, where human sulfur emissions are lower, the effects are easier to see, they write.

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