Operational Volume Scan Strategies for ARM's Cloud Radars

The U.S. Department of Energy's (DOE) Atmospheric Radiation Measurement (ARM) program is a key component of the DOE's research strategy to address global climate change. The ARM program is a highly focused observational and analytical research effort that compares observations with model calculations in the interest of accelerating improvements in both observational methodology and General Circulation Models (GCMs) and related models. ARM is currently converting its zenith pointing W-band cloud radar into the Scanning W-band ARM Cloud Radar (SWACR). Its inaugural deployment will be with the ARM Mobile Facility on Graciosa Island, Azores. This instrument will provide the capability to observe clouds in three spatial dimensions. Although ARM has made use of scanning precipitation radars in field campaigns, this will be the first attempt by ARM to observe clouds in three dimensions on a 24/7 operational basis and its first attempt to develop a 3-dimensional observational data product. This is an important task since the requirement for the ARM scanning cloud radars is to operate continuously and acquire cloud information in different climate regimes. We will outline the basic technical specification for scanning cloud radars, the basic “targets” of interest, present scanning strategies for different cloud scenes and identify some basic data products.