Decadal climate variability of precipitation over western North America
- Climate Research Scripps Institution of Oceanography, La Jolla, CA (United States)
- NOAA-ERL-CDC, Boulder, CO (United States)
Data on regionally-coherent interdecadal fluctuations in precipitation patterns over western North America are presented in this paper. Possible links between global circulation patterns and precipitation patterns are examined. Rotated principal components of precipitation show that the spatial scale of interdecadal precipitation anomalies in the West is regional, with several distinct, persistently anomalous wet or dry features. Correlations with decadal filtered sea level pressure anomalies reveal regional to large scale anomaly signatures similar to those involved in producing short period precipitation fluctuations. Inspection of circulation patterns at the monthly level indicates that the decadal precipitation shifts involve changes in the frequency of several primary monthly extratropical North Pacific circulation patterns. The anomalous sea surface temperature is also connected with decadal precipitation fluctuations, and results are consistent with the linkages to the atmospheric circulation. Considering the large scale connections of some of the regional precipitation patterns with circulation and sea surface temperature, it is hypothesized that the climate system contains globally organized precipitation anomalies on scales larger than the subset of western North America studied. For example, the Southwest decadal precipitation rotated principal component is closely aligned, but out of phase with, a global precipitation pattern that includes the Sahel in Africa. 2 refs., 3 figs.
- OSTI ID:
- 535475
- Report Number(s):
- CONF-970207-; TRN: 97:005076-0006
- Resource Relation:
- Conference: 77. annual meeting of the American Meteorological Society, Long Beach, CA (United States), 2-7 Feb 1997; Other Information: PBD: 1997; Related Information: Is Part Of Eighth symposium on global change studies; PB: 402 p.
- Country of Publication:
- United States
- Language:
- English
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