Improved Microwave Radiometer Retrieval Data Produced for 2 ARM Sites

Published: 25 August 2022

This quicklook image contains three plots from ARM's Southern Great Plains Central Facility. — This Microwave Radiometer Retrievals (MWRRET) quicklook image provides information from ARM’s Southern Great Plains Central Facility on July 2, 2021. The image shows, from top to bottom, observed brightness temperatures at 23.8 GHz (blue) and 31.4 GHz (red); retrieved precipitable water vapor from the physical method (blue) and statistical method (green); and retrieved liquid water path from the physical method (blue) and statistical method (green).

New level 2 (c2) files are now available from the Microwave Radiometer Retrievals value-added product (MWRRET VAP). This release covers 2020 and 2021 at the Atmospheric Radiation Measurement (ARM) user facility’s Southern Great Plains Central Facility near Lamont, Oklahoma, and 2018 through 2021 at ARM’s North Slope of Alaska atmospheric observatory.

MWRRET retrieves column precipitable water vapor and liquid water path—both important variables to understanding radiative transfer in the atmosphere and clouds—from ARM’s 2-channel microwave radiometers (23.8 and 31.4 GHz). The VAP uses a physical retrieval methodology that provides improved retrievals over the standard statistical coefficient method.

MWRRET has two stages of processing. In the first stage, the VAP is run in near-real time to produce timely operational .c1-level files. The second stage of processing, which produces .c2-level files, is run yearly. During this stage, improved offsets are applied to the 23.8 GHz channel, improving the precipitable water vapor retrievals. In addition, this stage uses cloud vertical extent information from the Active Remote Sensing of CLouds (ARSCL) VAP rather than ceilometer data to get the correct temperature of the liquid water layers in the atmosphere.

When available, .c2-level files should be used because they are expected to be the most accurate.

More information on MWRRET can be found on the VAP web page. Feedback on the VAP can be sent to ARM translator Damao Zhang.

Access these data in the ARM Data Center. (Go here to request an account to download the data.)

To cite the MWRRET data, please use doi:10.5439/1027369.

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