The island nations of the tropical Pacific are particularly vulnerable to climate change. With many islands relying on rainfall for nearly all of their fresh water, changes in rainfall patterns are of particular importance to Pacific Islanders. On a local scale, the temporal distribution of rainfall is just as important as the total amount. Rainfall is also a key component of atmosphere-ocean heat exchange here, and is thus an important driver of the weather in a region that in turn influences the global climate system.

One of the predicted consequences of climate change is an accelerated hydrologic cycle that will result in both more intense rainfall events and more severe droughts. Indeed, such changes have been observed in the tropical Pacific and elsewhere. Ideally, the general circulation models (GCMs) used to predict climate changes should capture these changes in rainfall extremes as well as the global rainfall distribution.

Previous work has compared GCM output from the Climate of the 20th Century Experiment (20C3M) to rain gauge data from the Pacific Rainfall Program (PACRAIN). This preliminary analysis looked at trends in several extreme rainfall parameters, but no definitive patterns were found. Current work is focused on a more robust trend detection method that is appropriate for the nature of the parameters. Results highlighting the comparisons and patterns identified will be discussed.