Cloud Microphysics VAP Evaluation Data Available for MC3E Field Campaign

Published: 18 May 2020

Cloud microphysical properties affect cloud radiative heating, precipitation formation, and aerosol-cloud interactions, among other important atmospheric processes. A value-added product (VAP) that calculates cloud microphysical properties now provides evaluation data for the 2011 Midlatitude Continental Convective Clouds Experiment (MC3E) in Oklahoma.

The Improved MICROBASE Product with Uncertainties (MICROBASEKAPLUS) provides continuous, high time resolution profiles of cloud microphysical properties such as 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.

Plots from sgpmicrobasekaplusM1.c1 datastream during MC3E campaign
The plots from the sgpmicrobasekaplusM1.c1 datastream show ice water content (left) and ice water content uncertainty (right) on June 1, 2011.

MICROBASEKAPLUS uses parameterizations identical to those used by the Atmospheric Radiation Measurement (ARM) user facility’s historical Continuous Baseline Microphysical Retrieval (MICROBASE) VAP 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 Active Remote Sensing of Clouds (ARSCL) product using Ka-Band ARM Zenith Radars (KAZR-ARSCL), the Interpolated Sounding (INTERPOLATEDSONDE) VAP, and the Microwave Radiometer Retrievals (MWRRET) VAP. The MICROBASEKAPLUS product is archived as daily data files. These files have a time resolution of 4 seconds and vertical resolution of 30 meters to 18,010 meters, which is consistent with the KAZR-ARSCL data resolutions.

MICROBASEKAPLUS evaluation data are available for MC3E from April 22 through June 7, 2011. Scientists can use these data now.

Plots from sgpmicrobasekaplusM1.c1 datastream during MC3E campaign
The plots from the sgpmicrobasekaplusM1.c1 datastream show liquid effective radius (left) and liquid effective radius uncertainty (right) on June 1, 2011.

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, comparisons to in situ measurements, and instrument simulator comparisons. 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 Michael Jensen, the MC3E principal investigator, or Meng Wang, data product developer. Such feedback will assist in improving the product before its full release.

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

To cite the MICROBASEKAPLUS data, please use doi:10.5439/1438196.

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), 10.1002/2013jd021112.

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