HR: 0800h
AN: GC11A-0127    [Abstracts]
TI: Analysis of trends in extreme hourly precipitation events in India
AU: * Roy, S
EM: ssr@miami.edu
AF: University of Miami, 225 Ferre Building, 100 Memorial Drive, Coral Gables, FL 33124,
AB: Variability and changes in the trends of extreme precipitation events, has been identified as one of the major results of global climate change. The latest report of the IPCC highlights the increasing trend in the frequency of extreme heavy precipitation events. In particular the report also highlights the increased frequency in the occurrence of intense precipitation events during the Indian summer monsoon at the regional scale. These findings are based on the analysis of daily precipitation data at both station level and modeling results for the Indian subcontinent. In view of the strong evidence indicating an increasing trend in extreme daily precipitation events, the present study focuses on the trends in extreme hourly precipitation events over the Indian subcontinent. Hourly precipitation data for over 80 stations were collected for the last 20 years (1980 to 2002) to examine the spatial patterns in overall trends in extreme heavy precipitation events at the seasonal scale. Unlike previous studies that only concentrate on the summer monsoon precipitation, the present study focuses on both summer and winter season precipitation events. In view of the existence of several different indices for measuring extreme precipitation events, some of the more effective indices have been used to determine the spatial and temporal variations in extreme hourly precipitation over the subcontinent. The trends in the following extreme precipitation indices for each station were analyzed: · Largest 1 hour event · Largest 3 hour total · Extreme frequency (90th percentile) · Extreme frequency (95th percentile) · Extreme frequency (97.5th percentile) Finally, the impact of global teleconnections in the form of ENSO, were also examined to reveal any significant role of teleconnections on the trends in hourly extreme precipitation events. The results of the present study have widespread hydrological implication especially for the areas along the foothills of Himalaya that are prone to intense flooding during the monsoon season. The spatial patterns of the trends in hourly extreme precipitation events will also be useful for arid and semi arid regions of western and central India for planning of flashflood mitigation measures.
DE: 1817 Extreme events
SC: Global Environmental Change [GC]
MN: 2007 Fall Meeting