Preliminary Analysis of the Nauru Island Effect Study Data

During the Nauru99 field experiment (held during June and July of 1999); the presence of an island effect on the cloud and radiation measurements recorded from the Atmospheric Radiation Cloud Station (ARCS) site at Nauru was identified. The island cloud effect occurs when moist air is advected over the island and the diurnal heating of the island (relative to the surrounding ocean) induces convection and cloud formation (Nordeen et al. 2001). The ARCS site was located on the leeward side of the island (relative to the prevailing easterly trade winds) due to a limited choice of available sites on Nauru. Although the increased cloudiness due to the island has a relatively small effect on the radiation budget in the region, it may cause the radiation and cloud measurements at the ARCS site to be biased relative to the surrounding ocean.