Rainfall

Changes in rainfall can have a wide-ranging impact on humans and ecosystems. On islands, where rainfall is often the primary source of all freshwater, extended dry periods (i.e., drought) affect drinking water supply. Drought also affects the agriculture, as well as streamflow necessary to maintain aquatic habitat. Heavy or extreme rainfall events can damage crops, increase soil erosion, and lead to in-land flooding that damages infrastructure. Runoff from excessive precipitation can also carry harmful pollutants into nearby water bodies, endangering aquatic species as well as human health.

In this section we look at three indicators of change in rainfall. Using observations from the Koror meteorological station we will create plots that show changes in the annual rainfall, dry conditions, and wet days. Dry days are defined as days below 1mm (0.04 inches) threshold. Wet days are defined as days above 1mm (0.04 inches). Heavy rainfall days are defined as days where rainfall is greater than 47mm (1.9 inches), the 95th percentile.