The Department of Energy's Atmospheric Radiation Measurement (ARM) program is designed to measure the components of the surface radiation balance and the properties of the atmospheric state which affect that balance. There are currently three sites in operation, one in the U.S. southern great plains, one in the tropical western Pacific (Manus Island, Papua New Guinea) and one in Barrow, Alaska.
The second tropical Western Pacific ARM site will be installed on the island republic of Nauru (0.4 S, 167 E) during the fall of 1998. Like the site at Manus, the Nauru site will include instruments to measure the surface radiation budget, column water vapor, cloudiness, and meteorological parameters. The site will include several important instruments that have not yet been implemented at Manus including a millimeter cloud radar and a whole sky imager. These instruments will provide a more complete assessment of the cloud distribution. We will show preliminary data from the the Nauru site and compare our observations with data from Manus.