Low frequency drought variability in the western US from paleoclimatic indicators and GCM projections
Abstract
Low-frequency hydrologic variations of the western US for the past 500 years contained in gridded tree-ring reconstructions of Palmer Drought Severity Index (PDSI), were compared to PDSI projections under climate change scenarios calculated from the output of general circulation models (GCMs). Tree-ring results suggest that bidecadal and pentadecadal PDSI oscillations have been a common feature of the climate of the western US at least for the past 500 years. These variations are though to be related to similar low-frequency climate variations from the Pacific and Atlantic Ocean basins. Future PDSI projections computed from the GCM estimates of precipitation and temperature, also contain significant multidecadal variations, as well as significant negative trends. Although precipitation exhibits very little trend in many of the GCM projections for the western US, warming temperatures will drive PDSI into the dry category more frequently in the future according to the GCM data. Regional structure and change of precipitation is inconsistent across models. However, warmer climate alone will produce more frequent scarcity of water availability
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2004
- Bibcode:
- 2004AGUFM.H24B..05H
- Keywords:
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- 1812 Drought;
- 1833 Hydroclimatology;
- 1854 Precipitation (3354);
- 1866 Soil moisture;
- 1884 Water supply