New Cloud Microphysics VAP Evaluation Data Available for 3 ARM Sites

Published: 20 April 2022

Four sample plots are stacked vertically: liquid water content, liquid effective radius, ice water content, and ice effective radius from the MICROBASEKAPLUS value-added product.
Sample plots are from the Cold-Air Outbreaks in the Marine Boundary Layer Experiment (COMBLE) near Andenes, Norway, and show the primary fields from MICROBASEKAPLUS (liquid water content, liquid effective radius, ice water content, ice effective radius) on May 25, 2020.

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.

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.

The new MICROBASEKAPLUS data are available for the 2019–2020 Cold-Air Outbreaks in the Marine Boundary Layer Experiment (COMBLE) near Andenes, Norway, and for ARM’s Southern Great Plains and Eastern North Atlantic atmospheric observatories through the end of 2020.

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).

To determine the cloud microphysical properties, MICROBASEKAPLUS uses a combination of data from the Ka-Band ARM Zenith Radars Active Remote Sensing of CLouds (KAZRARSCL) VAP, 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.

Scientists can use these data now. 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.

More information on MICROBASEKAPLUS is available on the VAP web page.

During this evaluation period, please send any product-related comments and suggestions to ARM translator Scott Giangrande, scientist Michael Jensen, or VAP developer Meng Wang. Such feedback will assist in improving the product before its full release.

Users can access the data sets from the ARM Data Center. (Go here to create an account to download the data.)

To cite the MICROBASEKAPLUS data, please use doi:10.5439/1768890.

Reference: Zhao C, S Xie, X Chen, MP Jensen, and M Dunn. 2014. “Quantifying uncertainties of cloud microphysical property retrievals with a perturbation method.” Journal of Geophysical Research: Atmospheres, 119(9),

# # #

ARM is a DOE Office of Science user facility operated by nine DOE national laboratories.