The supercooled liquid clouds found in the Arctic (Westwater et al. Radiometer LWP and precipitable water vapor retrievals based on oxygen and water vapor absorption models that are appropriate for
The dual-channel, microwave radiometer measures brightness temperatures at 23.8 GHz and 31.4 GHz. (Stokes and Schwartz 1994, Ackerman and Stokes 2003). Radiometer Dataīoth radiometers utilized here were operated at SHEBA by the Department of Energy's Atmospheric Radiation Measurement Program A missing hyperlink in the dates menu indicates that radar data does not exist for that day. Days with obviously erroneous radar data have been excluded from theĬloud microphysics processing. Operating optimally (such as on May 11, 1998). Necessarily guarantee reliable radar measurements, as an ARSCL-type radar file was generated even if the radar was not Optimally combined into a single radar product using an algorithm based on the DOE/ARM ARSCL (Active Remotely-SensedĬloud Locations) program, and interpolated to a 1 min-45 meter time-height grid. Typically these modes cycle every 9 s and data are collected at 45 m or 90 m range resolutions. All retrievals are based on continuous, vertically-pointing, radar measurements that were originallyĬollected using 4 different operating modes with variable sensitivies optimized for different cloud and precipitation situations. 1998) was operated by the NOAA Environmental Technology The 35-GHz, Ka-band Millimeter Cloud Radar (MMCR, Moran et al. Noted that these seemingly simple equations were derived through a complex line of reasoning, and the fullĭerivations should be carefully examined in the indicated references. Reduced equations have been provided to show how the cloud microphysics were calculated. In the following sections, for the retrieval methods where iteration and/or polynomial fits were not utilized, While not definitive, the ice retrieval uncertainties are expected to be 30-50% for particle size and 50-100%įor ice water content and the liquid retrieval uncertainties are expected to be 20-40% for droplet size and Several studies have addressed the issue of errors associated with radar-based cloud retrievals. Itself retrieved from radiometric brightness temperatures. The liquid water path (LWP) from the microwave radiometer is a retrieval-based-on-a-retrieval, since LWP is It should also be considered that the radar-radiometer liquid cloud retrieval technique that utilizes On particle size, and parameterizations relating radar reflectivities to cloud properties based on aircraftĭata. These may include such approximations as spherical ice particles, gamma,Įxponential, or lognormal droplet/ice particle size distributions, ice particle densities parameterized Is that they are observation-based-retrievals, not direct measurements. The most important thing to remember when using the cloud microphysical values on this CD SHEBA Version 2 Notes (January, 2004) Retrievals are Retrievals, Not Measurements!
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