CORRELATIONS BETWEEN AREAL PRECIPITATION AND 850-MILLIBAR GEOPOTENTIAL HEIGHT

Abstract

Geopotential heights of the 850-mb surface at 499 grid points over one-half of the Northern Hemisphere, extending from 10°E westward to 170°W, were correlated with daily precipitation observations over California and an area in the Eastern United States on 401 January and February days. Correlations as high as 0.69 were obtained between 850-mb heights and California precipitation. The statistical significance of the maximum correlation obtained over the one-half hemisphere area exceeded the 5-percent level for all periods of less than 5 days. The maximum correlation between heights and precipitation observed in the Eastern United States was ?0.44 and the correlations were significant at the 5-percent level for all periods of less than 3 days. Since correlations between 850-mb heights and subsequent precipitation exceed autocorrelations except for short periods of time, it is proposed that 850-mb height observations replace or supplement persistence in conditional climatologies of precipitation.