Wednesday, 6 August 2003
Ground radar–based ice cloud microphysical retrievals during the CRYSTAL–FACE field campaign
The NOAA Environmental Technology Laboratory deployed its portable cloud observatory (NPCO) at the Eastern ground site during the observational period of the Cirrus Regional Study of Tropical Anvils and Cirrus Layers - Florida Area Cirrus Experiment (CRYSTAL-FACE) field campaign. This field campaign was conducted to study tropical cirrus and especially anvil cirrus and their radiative impact. The NOAA NPCO consists of a vertically-pointed 8 mm cloud Doppler radar (MMCR), and IR radiometer (10.6-11.3 micron band width) and 3 - channel microwave radiometer (20.6, 31.6 and 90 GHz ). The NPCO instrumentation was operational for about 95% of the duration of the campaign (July 2002). A suite of retrieval methods was developed at ETL for estimations of vertical profiles of such ice cloud microphysical parameters as ice water content (IWC) , cloud particle characteristic size (e.g., median size), and cloud extinction coefficient. The different methods use different input information and have differing applicability domains, though these domains partially overlap. Some methods are more preferable than others depending on the cloud scene. The use of different methods allows better understanding of uncertainties associated with different remote sensing approaches. This study presents some results of the retrievals, discusses retrieval uncertainties and the mutual consistency of different retrieval methods and shows some preliminary statistics on ice cloud microphysical parameters. It is shown, for example, that microphysical properties of anvils are quite different from those in the synoptically-generated cirrus clouds.