Harmonic and simple kriging analyses of diurnal precipitation patterns in Puerto Rico

Relatively large, topographically complex tropical islands can produce diurnal precipitation patterns that vary considerably over relatively short distances. In this investigation, we assembled a variety of databases to analyze diurnal rainfall patterns in Puerto Rico. We found strong diurnal cycles for all parts of the island with times of maximum frequency or total that ranged from pre-dawn in the east to mid-afternoon in the west. The pattern is similar to findings from Hawaii, and appears related to the daily pattern of katabatic and anabatic winds interaction with the predominant easterly trade winds. The diurnal pattern in rainfall was consistent through the year and not significantly affected by local sea-surface temperatures, El Niño-Southern Oscillation, and/or the North Atlantic Oscillation.