The ARM Millimeter Wave Cloud Radars (MMCRs) and the Active Remote Sensing of Clouds (ARSCL) Value Added Product (VAP)
- Pennsylvania State Univ., University Park, PA (United States)
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- National Oceanic and Atmospheric Administration (NOAA), Seattle, WA (United States)
- Univ. of Utah, Salt Lake City, UT (United States)
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Over the past decade, the U.S. Department of Energy (DOE), through the Atmospheric Radiation Measurement (ARM) Program, has supported the development of several millimeter wavelength radars for the study of clouds. This effort has culminated in the development and construction of a 35-GHz radar system by the Environmental Technology Laboratory (ETL) of the National Oceanic and Atmospheric Administration (NOAA). Radar systems based on the NOAA ETL design are now operating at the DOE ARM sites located at the Southern Great Plains (SGP) Central Facility in central Oklahoma, on the islands of Nauru and Manus, Papua New Guinea, in the Tropical Western Pacific (TWP), and at Barrow on the North Slope of Alaska (NSA). These radars have come to be called the Millimeter Wave Cloud Radars (MMCRs). The importance of the MMCRs to the DOE ARM Program’s strategy for remote sensing of clouds is outlined. The MMCRs are designed as a remote sensing tool that can accurately detect almost all of the hydrometeors present in the atmosphere. To illustrate the difficulty of this task, the various types of hydrometeors that can occur in the atmosphere are considered in the context of detection by the MMCRs. Having outlined the nature of the remote sensing problem, a discussion ensues of the NOAA ETL design of the MMCR. Next, we present the operational modes of the MMCRs and discuss them in some detail to illustrate the nature of the cloud products that are, and will be, derived from the MMCRs on a continuous basis. The first set of products derived from MMCR data is based on detection of the significant returns in the data and subsequent classification of these detections as due either to clutter or to atmospheric hydrometeors. From these detections one can identify, as a function of time and height, regions of the atmosphere that contain hydrometeors. Using radar to conclusively identify regions of the atmosphere that do not contain any hydrometeors, such as 4 pm radius cloud drops far from the radar, is generally not possible. With these limitations in mind, one can use significant radar detections, together with radar Doppler moments and/or spectra, lidar and passive radiation measurements, to estimate geometric boundaries of clouds, cloud water contents, and cloud particle sizes. One effort for identifying significant returns in radar data and combining these detections with lidar estimates of cloud base height is called the Active Remote Sensing of CLouds (ARSCL) value added procedure (VAP). The outputs of this procedure are time-height maps of radar reflectivity, radar Doppler velocity, radar Doppler spectral width, and cloud base height estimates from laser ceilometers and Micropulse Lidars (MPLs). These products allow the geometric extent of clouds to be mapped and provide information on the distribution, size, and motions of the particles within cloud. The important elements of the ARSCL VAP are discussed and the products output by it are documented and illustrated. A reader who understands the contents of Sections 3 and 4 will be in a position to interpret the meaning, range of validity, and limitations of the ARSCL VAP and its products. The document ends with discussions of a few data quality issues, of how to retrieve data from the archive, and of some outstanding problems. Appendices A1, A2, and A3 contain the ARSCL VAP input datastreams, flow chart, and product variable lists, respectively.
- Research Organization:
- DOE Office of Science Atmospheric Radiation Measurement (ARM) Program (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Biological and Environmental Research (BER). Earth and Environmental Systems Science Division
- DOE Contract Number:
- AC05-7601830
- OSTI ID:
- 1808567
- Report Number(s):
- DOE/SC-ARM/VAP-002.1; TRN: US2300640
- Country of Publication:
- United States
- Language:
- English
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