HR: 08:00h
AN: A41A-01    [Abstracts]
TI: Pentad Evolution of the 1988 Drought and 1993 Flood over the Great Plains: A NARR perspective
AU: * Weaver, S J
EM: sweaver@atmos.umd.edu
AF: Department of Atmospheric and Oceanic Science, University of Maryland, 4337 CSS Bldg, College Park, MD 20742-2425, United States
AU: Nigam, S
EM: nigam@atmos.umd.edu
AF: Department of Atmospheric and Oceanic Science, University of Maryland, 4337 CSS Bldg, College Park, MD 20742-2425, United States
AB: The 1988 drought and 1993 flood in the central United States were among the most extreme climatic events in recent decades. The socioeconomic impact of these episodes was massive, with a price tag in the tens of billions of dollars and significant loss of life and property. Pentad (5-day averaged) evolution of these two events is studied using the 27-year precipitation assimilating North American Regional Reanalysis (NARR). The use of an improved hydroclimate dataset allows the rapidly evolving (sub-monthly) structure of the regional circulation and land surface anomalies during these two extreme events to emerge on a scale never before realized. This study focuses on the spatial and temporal relationships between the Great Plains low-level jet (GPLLJ), precipitation, and evaporation during MJJ in 1988 and 1993. The rapidly evolving hydroclimate anomalies reveal the dominance of GPLLJ induced moisture flux convergence over local precipitation recycling. Land-atmosphere impacts on GPLLJ modulation over the southern plains show a connection to a preferred mode of GPLLJ variability diagnosed through EOF analysis. While indicative of a land surface influence on the GPLLJ, the infrequent occurrence of this mode (12%) (as opposed to higher modes which are linked to large scale remote circulation variations) suggests the primacy of remote circulation influences in generating the GPLLJ and precipitation anomalies during extreme hydroclimatic events. July 1993 precipitation is linked to the antecedent winter ENSO and contemporaneous NAO further suggesting a role for known large scale climate variations on summertime North American extreme hydroclimate episodes.
DE: 1817 Extreme events
DE: 3305 Climate change and variability (1616, 1635, 3309, 4215, 4513)
DE: 3309 Climatology (1616, 1620, 3305, 4215, 8408)
SC: Atmospheric Sciences [A]
MN: 2007 Joint Assembly