A Continuous Baseline Microphysical Retrieval (MICROBASE): Status of SGP Version 1.2 and Prototype TWP Version

Miller, M.A.(a), Johnson, K.L.(a), Jensen, M.P.(b), Mace, G.G.(c), Dong, X.(d), and Vogelmann, A.M.(a), Brookhaven National Laboratory (a), Columbia University (b), University of Utah (c), University of North Dakota (d)
Fourteenth Atmospheric Radiation Measurement (ARM) Science Team Meeting

The interaction of clouds with incoming and outgoing radiation streams produces discontinuous regions of heating and cooling within the atmospheric column. These regions can influence the atmospheric circulations at multiple scales, as well as modify the existing cloud structures. The Broadband Heating Rate Project (BBHRP) within ARM has the goal of producing instantaneous snapshots of the heating and cooling rate profiles in the narrow column above the active sensors at each of the ARM Climate Research User Facilities (ACRUF) and in a larger volume around the sites that is the size of a typical grid cell in a Global Climate Model. To produce the required heating and cooling rate profiles, it is necessary to specify the cloud location and microphysical structure in radiation codes that perform calculations for the column above the active sensors and over the surrounding GCM-sized domain. In response to this need, a continuous baseline microphysical retrieval (MICROBASE) value-added procedure was created. The initial version of MICROBASE, version 1.0, computed the liquid and ice water contents from radar reflectivity according to simple transformations found in the literature. It also employed simple parameterizations of the droplet and ice crystal size distributions found in the literature, as well as an ad-hoc treatment of mixed-phase clouds. An improved version of MICROBASE uses linear scaling of the reflectivity-retrieved liquid water contents based on the instantaneous integrated liquid water contents measured by the microwave radiometer (MWR). The use of MICROBASE has improved the accuracy of ARM Single Column Models, as shown in a companion poster. This poster describes MICROBASE Version 1.2. Recent efforts by Dong and Mace and Stephens have yielded additional candidate non-conditional retrieval schemes. A plan to test the efficacy of these retrievals was formulated by the Cloud Properties Working Group during its autumn meeting and this poster describes early results from that exercise. The initial focus of the BBHRP project was the Southern Great Plains ACRUF, although plans are being formulated for the other sites.In response to an immediate need within the ARM Science Team, a prototype version of MICROBASE was devised for the Tropical Western Pacific ACRUF. The prototype version uses reflectivity-ice water content transformations suggested by Jensen et al., 2001, which are based on results from the Maritime Continent Convection Experiment (MCTEX). Results from this new prototype version are used in a companion poster.

Note: This is the poster abstract presented at the meeting; an extended version was not provided by the author(s).