Report Number: 102
Year: 2003

Creation of a 50-Year Rainfall Database, Annual Rainfall Climatology, and Annual Rainfall Distribution Map for Guam

Since the early 1950s, there has been considerable interest in the rainfall on Guam, especially by the US military and the US Geological Survey (USGS). Since 1950, over 60 government-sponsored rain gauge sites have operated on Guam. Unfortunately, the length of record of most of the sites is short, in many cases incomplete, and in some cases unreliable.

The few rainfall distribution studies for Guam have been based on limited data. As a result, the rainfall distribution patterns have been greatly oversimplified or incorrectly analyzed, and the actual rainfall gradients have been largely ignored. The purpose of this study is to evaluate the available data, then to use the acceptable data to build a 50-year rainfall database for selected sites on Guam. The resulting database provides a long-term rainfall climatology and an annual rainfall distribution map for the island.

Mark A. Lander
Charles "Chip" P. Guard