Atmospheric Sciences & Global Change
Island-Induced Cloud Plumes Influence Tropical Atmospheric Measurements, Surface Radiation
A key objective of the U.S. Department of Energy's Atmospheric Radiation Measurement (ARM) Program is to identify interactions between the processes that determine the radiative properties of an atmospheric column, including clouds and the underlying surface. Early results of ARM's Nauru Island Effects Study (NIES) provide important new information on the effect of small tropical islands on local meteorology. Principal findings are that the small island of Nauru, one of three sites that make up ARM's Tropical Western Pacific locale, increases the amount of low cloud on the leeward side of the island from about 20% cloud cover to 30% cloud cover. The amount of middle and high cloud is not affected. This study has enabled ARM scientists to develop analysis techniques that can detect when an island influence is occurring and how surface measurements may be affected by the island-induced clouds. The study is also allowing scientists to quantify the extent of the island influence on cloud statistics and the impact on surface radiation. This information is important for the ARM Program, as well as for other programs that maintain small island measurement sites.