The atmospheric radiation measurement program cloud radars: Operational modes

During the past decade, the U.S. Department of Energy (DOE), through the At mospheric Radiation Measurement (ARM) Program, has supported the developmen t of several millimeter-wavelength radars for the study of clouds. This eff ort has culminated in the development and construction of a 35-GHz radar sy stem by the Environmental Technology Laboratory (ETL) of the National Ocean ic and Atmospheric Administration (NOAA). Radar systems based on the NOAA E TL design are now operating at the DOE ARM Southern Great Plains central fa cility in central Oklahoma and the DOE ARM North Slope of Alaska site near Barrow, Alaska. Operational systems are expected to come online within the next year at the DOE ARM tropical western Pacific sites located at Manus, P apua New Guinea, and Nauru. In order for these radars to detect the full ra nge of atmospheric hydrometeors, specific modes of operation must be implem ented on them that are tuned to accurately detect the reflectivities of spe cific types of hydrometeors. The set of four operational modes that are cur rently in use on these radars are presented and discussed. The characterist ics of the data produced by these modes of operation are also presented in order to illustrate the nature of the cloud products that are, and will be, derived from them on a continuous basis.