19 March 2024
Cloud microphysical properties affect cloud radiative heating, precipitation formation, and aerosol-cloud interactions, among other important atmospheric processes. New evaluation data are now available from a value-added product (VAP) that builds upon the Atmospheric Radiation Measurement (ARM) user facility’s historical Continuous Baseline Microphysical Retrieval (MICROBASE) VAP.
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The Improved MICROBASE Product with Uncertainties (MICROBASEKAPLUS) provides continuous, high-time-resolution profiles of cloud microphysical properties such as the liquid/ice water content and liquid/ice effective radius. The VAP was primarily developed for estimating radiative heating rate profiles, but scientists can use it for diverse applications, including evaluation of model cloud parameterizations, process studies of precipitation formation, and cloud particle phase partitioning.
To determine the cloud microphysical properties, MICROBASEKAPLUS uses a combination of data from the Active Remote Sensing of CLouds (ARSCL) product using Ka-Band ARM Zenith Radars (KAZRARSCL), the Interpolated Sonde (INTERPSONDE) VAP, and the Microwave Radiometer Retrievals (MWRRET) VAP.
The MICROBASEKAPLUS product is archived as daily data files, with a time resolution of 4 seconds and vertical resolution of 30 meters to 18,010 meters, which is consistent with the KAZRARSCL data resolution.
MICROBASEKAPLUS uses parameterizations identical to those used by MICROBASE for determining the liquid/ice water content and liquid/ice effective radius. However, MICROBASEKAPLUS adds uncertainties to these quantities using a perturbation method first applied through the Atmospheric System Research (ASR) Quantifying Uncertainty in Cloud Retrievals (QUICR) science focus group (Zhao et al. 2014).
A continuous baseline microphysical product for the W-Band ARM Cloud Radar, called MICROBASEW, shares the same core retrieval algorithms with MICROBASEKAPLUS.
Ongoing work aims to use MICROBASEKAPLUS within the ARM Operational Ground-Based Retrieval Evaluation for Clouds (OGRE-CLOUDS) framework, evaluating improvements to cloud microphysics retrievals through radiative closure studies, and comparisons to instrument observations. Through this process, the development team anticipates a continuous improvement of the cloud microphysical estimates.
During this evaluation period, please send any product-related comments and suggestions to ARM translator Scott Giangrande, principal investigator Michael Jensen, or VAP developer Meng Wang. Such feedback will assist in improving the product before its full release.