Cloud and Radiatino Observation at the ARM Climate Research Facility Sites

Abstract
The Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF) is a DOE national user facility that includes multiple long-term field stations at locations around the world. ACRF operates sites in the central United States, the North Slope of Alaska, and at three locations in the tropical Pacific. ACRF also includes a mobile platform that is currently deployed in the Black Forrest in Germany and finally, ACRF manages an airborne measurement program. Each ACRF site provides measurements of the surface radiation budget and atmospheric parameters that impact that budget with an emphasis on measurements of cloud properties. Cloud properties including vertical distribution, horizontal extent, and water content are measured with a combination of active and passive remote sensors. The core sensors for cloud retrievals are the millimeter wavelength cloud radar, elastic backscatter lidar, and microwave radiometer. Another key measurement is the vertical water vapor profile. This profile is important for determining radiative heating rates. Time series of humidity are obtained with periodic radiosonde profiles combined with measurements of column integrated water vapor from the microwave radiometer. ARM is developing a variety of products from its suite of measurements to facilitate their application to climate model validation and process studies. In addition to vertical profiles of cloud properties and water vapor, a product currently under development is a time series of broadband heating rate profiles for each site. Preliminary radiative profiles are now available for the central US and tropical sites.

James Maher is Technical Director for the ARM Climate Research Facility at the Pacific Northwest National Laboratory