HR: 1340h
AN: H13E-0469    [Abstracts]
TI: Spatial and temporal characteristics of US drought, 1950-2000
AU: * Sheffield, J
EM: justin@princeton.edu
AF: Princeton University, Dept. Civil and Environmental Engineering, Princeton, NJ 08544 United States
AU: Wood, E F
EM: efwood@princeton.edu
AF: Princeton University, Dept. Civil and Environmental Engineering, Princeton, NJ 08544 United States
AB: Drought accounts for a large portion of economic and environmental losses from natural hazards in the US. It generally develops slowly over long time scales (seasonal to annual), may have large spatial coverage and exhibit long-term persistence that ensures that its impacts can be widespread and long-felt. Drought can be highly variable in space due to variability in climate forcings and perhaps more importantly through smaller-scale land surface heterogeneities. Thus monitoring and prediction can present considerable challenges, notwithstanding the practical difficulties in observing soil moisture over large scales. This study investigates some of the issues related to the spatial and temporal characteristics of drought over the US. We use as the basis of this study a drought index based on soil moisture data derived from a long-term (1950-1999), high resolution (1/8th degree) simulation of the land surface water budget over the conterminous US using the Variable Infiltration Capacity (VIC) model. Comparison of the occurrence of drought at regional scales shows distinct coherence between certain neighboring regions but this varies in time. We explore this in further detail to investigate issues such as the scale at which coherence breaks down and how coherence and variability change across the country (with respect to climate, topography, and vegetation). The analysis also reveals high persistence in drought occurrence (and wet spells) across the western US. In contrast the eastern US shows high temporal variability as dictated by shorter-term climate variability. Persistent signals in soil moisture and drought have been linked to large-scale climate oscillations and we investigate this through the analysis of teleconnections. These findings are also dependent on the soil horizon in question, as soil moisture at different depths varies over different time scales and we look at how spatial variability and temporal persistence varies through the soil profile.
DE: 3309 Climatology (1620)
DE: 1812 Drought
DE: 1866 Soil moisture
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting