HR: 08:30h
AN: H21I-03 INVITED     [Abstracts]
TI: Means, Variability and Extremes of Precipitation in the Global Climate as Determined by the 25-year GEWEX/GPCP Data Set
AU: * Adler, R F
EM: Robert.F.Adler@nasa.gov
AF: NASA Goddard Space Flight Center, Mail Code 912, Greenbelt, MD 20771 United States
AU: Gu, G
AF: University of Maryland Baltimore County, Mail Code 912, Greenbelt, 20771
AU: Curtis, S
AF: East Carolina University, Brewster A-232, Greenville, NC 27858
AU: Huffman, G
AF: SSAI/NASA Goddard, Mail Code 912, Greenbelt, MD 20771
AB: The Global Precipitation Climatology Project (GPCP) 25-year precipitation data set is used as a basis to evaluate the mean state, variability and extremes of global and regional scales of precipitation. The uncertainties of these characteristics of the data set are evaluated by examination of other, parallel data sets and examination of shorter periods with higher quality data (e.g., TRMM). The global and regional means are assessed for uncertainty by comparing with other satellite and gauge data sets, both globally and regionally. The GPCP global mean of 2.6 mm/day is divided into values of ocean and land and major latitude bands (Tropics, mid-latitudes, etc.). Seasonal variations globally and by region are shown and uncertainties estimated. The variability of precipitation year-to-year is shown to be related to ENSO variations and volcanoes and is evaluated in relation to the overall lack of a significant global trend. The GPCP data set necessarily has a heterogeneous time series of input data sources, so part of the assessment described above is to test the initial results for potential influence by major data boundaries in the record. Regional trends are also analyzed to determine validity and correlation with other long-term data sets related to the hydrological cycle (e.g., clouds and ocean surface fluxes). Statistics of extremes (both wet and dry) are analyzed at the monthly time scale for the 25 years. The validity of a preliminary result of increasing frequency of extreme monthly values during the period will be a focus. Daily values for an eight-year period are also examined for variation in extremes and compared to the longer monthly-based study.
DE: 3354 Precipitation (1854)
DE: 1655 Water cycles (1836)
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting