HR: 0800h
AN: GC11A-0131    [Abstracts]
TI: Spatio-temporal analysis of extreme rainfall trends associated with the Indian monsoon
AU: * Kiran, C
EM: cb2322@columbia.edu
AF: Doctoral Student, School of International and Public Affairs, Columbia University, 420 West 118th Street, New York, NY 10027, United States
AU: Lall, U
EM: ula2@columbia.edu
AF: Professor, Earth & Environmental Engineering, Columbia University, 918 Mudd, 500 W 120th Street, New York, NY 10025, United States
AU: Kwon, H
EM: hk2273@columbia.edu
AF: Associate Research Scientist, Earth & Environmental Engineering, Columbia University, 918 Mudd, 500 W 120th Street, New York, NY 10025, United States
AB: This study is a statistical assessment of the presence of linear trends in clearly defined extremes of daily precipitation data, and makes use of a (relatively) long time-series of gridded daily data for India to clarify a few points, including the presence of trends, at the grid level, the spatial signature of these trends. Much of literature conjectures an intensifying summer monsoonal precipitation, and in general, an intensification of the monsoonal patterns over the Indian peninsula; to date, however, convincing statistical evidence for increased extremes of precipitation have been rarely found. This study is an attempt to answer the first of the two important questions investigated in Climate literature, on the existence of trends in precipitation extremes, and the seasonal aspects of such a change (given that much of literature is focused on changes only during the summer monsoon), since without evidence of such trends, arguments of alterations in monsoonal precipitation following global warming must probably undergo some revisions, especially given the difficulty in consistently and accurately predicting even the average monsoonal rainfall using Climate models. This study attempts to separately estimate trends in two different aspects of precipitation extremes, intensity of events and frequency of events, unlike much of literature which focuses on one or the other, given the suspicion that the two maybe related (an increase in the one may, for instance, be easily conjectured a result of a decrease in the other); further, events in and out-of (monsoon) season are treated separately (as well as in the usual aggregated manner), thereby answering the question posed in as comprehensive a manner as possible. In-season, trends in both intensity and frequency appear to be not significant over most parts, and where significant, predominantly negative, with a few positive (significant) trends in frequency being evident; there is, further, no spatial signature in these (significant) trends.
DE: 1630 Impacts of global change (1225)
DE: 1637 Regional climate change
DE: 1807 Climate impacts
DE: 1817 Extreme events
DE: 3305 Climate change and variability (1616, 1635, 3309, 4215, 4513)
SC: Global Environmental Change [GC]
MN: 2007 Fall Meeting