11.5 Daily Precipitation Extremes over Eastern United States: Variability and Change Stemming from North Atlantic Tropical Cyclones

Thursday, 14 January 2016: 9:30 AM
Room 226/227 ( New Orleans Ernest N. Morial Convention Center)
Nirajan Dhakal, Spelman College, Atlanta, GA; and S. Jain

Almost every year, north Atlantic tropical cyclones are responsible for social catastrophe and economic loss along the eastern United States. In this study, we analyzed the contribution of the north Atlantic tropical cyclones to the variability and trends in extreme precipitation and the temporal changes therein for 667 USHCN stations across eastern United States. Analysis reveals that for some coastal stretches, such as the Carolinas, as high as 40 % of the extreme precipitation events during 1950-2011 are associated with tropical cyclones. Assessment of temporal change in the number of extreme precipitation events associated with tropical cyclones based on two 31-year blocks (1950-1980 and 1981-2011) of data showed that about 58% of the stations experience increases for the recent time period. Our approach casts the changing nature of precipitation extremes within a hydroclimatic analysis framework with two distinct tenets: (a) mixed distribution approach, and (b) inclusion of appropriate climatic covariates. A Principal component analysis revealed dramatic increase in the correlation between leading PCs (PC1) of extreme precipitation and Accumulated Cyclone Energy (ACE) index for the recent time period. Such results are important for proper characterization of extreme value distribution (EVD) for the design and reassessment of flood-controlling infrastructure.
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