ARM Radar Infrastructure for Global and Regional Climate Study

The Atmospheric Radiation Measurement (ARM) Climate Research Facility is a U.S. Department of Energy (DOE) atmospheric measurements and observations facility for the study of global and regional climate by the research community. The scientific motivation for global and regional climate study is to better understand the atmospheric processes that govern global climate and to develop accurate representative global climate models. Cloud and precipitation systems play a significant role in the energy and hydrological cycles of the atmosphere. The ARM facility is establishing a cloud and precipitation radar infrastructure through the American Recovery and Reinvestment Act of 2009 to enable the observation of cloud and precipitation systems under various climate regimes. The ARM radars are deployed at four fixed sites and on two mobile facilities for regional climate studies. The four fixed sites are at Southern Great Plains in Oklahoma, North Slope of Alaska in Barrow, Tropical Western Pacific Darwin in Australia and Tropical Western Pacific Manus Island in Papua New Guinea. These radars will be located with the baseline instrument suites at the ARM sites for comparative measurements. The newly added radars to the ARM radar infrastructure consist of four X-band scanning ARM precipitation radars (X-SAPRs), two C-band scanning ARM precipitation radars (C-SAPRs), three X/Ka-band scanning ARM cloud radars (X/Ka-SACRs), three Ka/W-band scanning ARM cloud radars (Ka/W-SACRs), and the replacement of the venerable MMCRs with the new Ka-band ARM zenith radars (KAZRs). In addition, ARM will continue to field the zenith-pointing W-band ARM cloud radar (WACR) and the scanning W-band cloud radar (SWACR). There are two main objectives for the ARM radars deployed around the world. First, maintain and augment the collection of comprehensive and continuous long-term data sets that provide observations of cloud and precipitation over a wide range of environmental conditions. Second, supplement the long-term data with shorter-duration field campaigns for targeted atmospheric processes. This paper presents an overview of ARM radar infrastructure showcasing its observational capability to facilitate the quantification of cloud and precipitation interactions to improve fundamental process-level understanding of atmospheric systems.