HR: 0800h
AN: H21D-1381    [Abstracts]
TI: Space-Borne Ku-Band Radar Observations of Extreme Surface Water Conditions
AU: * Nghiem, S V
EM: Son.V.Nghiem@jpl.nasa.gov
AF: Jet Propulsion Laboratory, 4800 Oak Grove Drive, MS 300-235, Pasadena, CA 91109 United States
AB: Acceleration of the global water cycle may lead to an exacerbation of hydrologic extremes. A multitude of extreme events has occurred in the last decade over the world including droughts, floods, record snow accumulation, and minimal ice cover with severe environmental and socioeconomic impacts. This paper presents an overview of the capabilities of space-borne Ku-band radar to measure extreme conditions of surface water including liquid and solid phases on land, ice, and oceans. Ku-band backscatter data acquired globally by the QuikSCAT satellite scatterometer are used to obtain the results. Hurricane Katrina in 2005 is the deadliest and costliest in U.S. with far-reaching impacts. Radar results of surface water over southern and eastern U.S. reveal the extreme extent of precipitation water deposited on land surface compared to the case of Hurricane Ivan in 2004. Radar monitoring of surface water pattern in California shows the extreme prolonged duration of precipitation-induced water in the 2005 wettest winter season over a century causing widespread flooding and landslide. For drought monitoring, radar maps of precipitation frequency over the U.S. Midwest in summer seasons indicate a sharp change to a severe drought in 2003 from the most frequent rains in 2000. Kenya experienced the worst drought in 45 years affecting more than 3 million people in 2000 when the radar data over Nairobi identified the collapse of the long rain season. Since then, satellite radar time-series up to July 2005 shows the consistency of the annual bimodal precipitation seasons suggesting an improvement in the local drought conditions. In cold land regions, backscatter data map seasonal snowmelt processes showing large variabilities in time and in space over the northern hemisphere. Satellite Ku-band radar measurements of snow accumulation on the Greenland ice sheet identify and map the record snow accumulation in the first quarter of 2005, verified with field observations and measurements from surface station networks, providing an extreme amount of water mass equivalent to more than three times the total glacier discharge by calving over the same duration. In Antarctica, radar results discover extensive ice layer created by anomalous melt in 2005 in coastal areas to regions well inland with local melt detected for the first time ever in the data history. Over the Arctic, sea ice extent has remained in a minimal condition in summers in the past four consecutive years (2002-2005) and multi-year ice areas in winters are reduced as seen in radar mapping results. These Ku-band radar capabilities in observing water states from space lend strong supports to future satellite Ku-band radar systems dedicated to measure crucial hydrologic and cryospheric parameters specifically designed to meet accuracy and resolution requirements by science research and operational applications.
DE: 0736 Snow (1827, 1863)
DE: 0750 Sea ice (4540)
DE: 1812 Drought
DE: 1821 Floods
DE: 9820 Techniques applicable in three or more fields
SC: Hydrology [H]
MN: Fall Meeting 2005