Solar-irradiance variations and regional precipitation fluctuations in the Western USA

✍ Scribed by Charles A. Perr

• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 1012 KB
• Volume: 14
• Category: Article
• ISSN: 0899-8418
• DOI: 10.1002/joc.3370140903

✦ Synopsis

Abstract

Changes in total solar irradiance can be linked to changes in regional precipitation. A possible mechanism responsible for this linkage begins with the absorption of varying amounts of solar energy by the tropical oceans, which creates ocean temperature anomalies. These anomalies are then transported by major ocean currents to locations where the stored energy is released into the atmosphere, thereby altering atmospheric pressure and moisture patterns, which can ultimately affect regional precipitation.

Correlation coefficients between annual differences in empirically modelled solar‐irradiance variations and annual State‐divisional precipitation in the USA for the period 1950–1988 were computed with lag times of 0 to 7 years. The most significant correlations occur in the Pacific North‐west, with a lag time of 4 years, which is approximately equal to the travel time of water within the Pacific gyre from the western tropical Pacific Ocean to the Gulf of Alaska. Precipitation in the Desert South‐west correlates significantly with solar irradiance lagged 3 and 5 years, which suggests a link with ocean‐water temperature anomalies transported by the Equatorial Counter Current as well as the North Pacific gyre. With the correlations obtained, droughts coincide with periods of negative irradiance differences (dry high‐pressure development), and wet periods coincide with periods of positive differences (moist low‐pressure development).