The performance of the MM5 is compared to the gauge data for two wet seasons and for the largest precipitation events of each season. The cumulative MM5 precipitation forecasts for both seasons and for the sum of the largest events compare well with the precipitation measured by the gauges, although some of the individual events are significantly over or under forecast. This suggests that the MM5 is correctly reproducing the precipitation climatology in the vicinity of our gauges, but that errors for individual events may arise due to predictability issues.
A computationally simple model of orographic precipitation is shown to reproduce the major features of the precipitation pattern. This simple model can be coupled to landscape evolution models to examine the impact of long-term spatial variability in precipitation on the evolution of topography over thousands to millions of years.
Current work is concentrating on understanding the physical mechanisms responsible for the observed precipitation pattern, as well as predicting the robustness of the pattern under climate changes.