We analyze daily precipitation data from station and reanalysis data for the years 1900-2001 for regions of Arizona/New Mexico (AZ/NM) in order to identify dominant modes of variability of precipitation and coherence with large-scale circulation. Preliminary analyses of annual time series reveal that summer rainfall in the AZ/NM is modulated by large-scale, low-frequency (20-50 day) dynamics. Improved understanding of these interactions could lead to more accurate seasonal forecasting of precipitation, important for management of Western U. S. water resources and for GCM evaluation in climate change studies.
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