ARM

ARM Best Estimate Data Sets Updated for 2 ARM Observatories

The top figure shows relative humidity scaled, by total column amount from MWR, from sounding in height coordinate (%), from ARM's Southern Great Plains (SGP) atmospheric observatory in 2020. The y-axis represents height from 0 to 15 kilometers. The bottom figure shows surface precipitation from the SGP in 2020. The precipitation rate is from 0 to 25 mm/hour. The x-axis in both figures represents the calendar day in 2020 from 150 to 300.
The plots show ARMBEATM relative humidity (top) and surface precipitation (bottom) from May to October 2020 at ARM’s Southern Great Plains (SGP) atmospheric observatory.

The Atmospheric Radiation Measurement (ARM) user facility provides tailored datastreams known as ARM Best Estimate (ARMBE) data products for use in the evaluation of global earth system models.

The ARM Best Estimate Atmospheric Measurements (ARMBEATM) product contains basic atmospheric quantities, and ARM Best Estimate Cloud Radiation (ARMBECLDRAD) provides cloud and radiation quantities.

ARMBEATM data for ARM’s Southern Great Plains and North Slope of Alaska atmospheric observatories have been extended to cover the years 2019 and 2020.

In addition, ARMBECLDRAD code has been updated and used to reprocess data from 2011 through 2018 for both observatories. ARMBECLDRAD data have been extended to 2019 and 2020 using the updated code.

The figures show the difference between previously released ARMBECLDRAD data and reprocessed data that address an issue with the interpretation of micropulse lidar mask flags. The difference is apparent below 3 kilometers between 17 UTC and 20 UTC, when radar data are missing.
The figure compares cloud fraction in the previously released version of ARMBECLDRAD (top) and the reprocessed data (middle) derived from cloud measurements from the Ka-Band ARM Zenith Radar Active Remote Sensing of CLouds (KAZRARSCL) data product (bottom) on May 10, 2017, at the SGP. The difference between the previously released data and the reprocessed data appears below 3 kilometers between 17 and 20 UTC (Coordinated Universal Time), when radar data are missing (red circle). The old algorithm did not capture the low clouds purely detected by the micropulse lidar because of an issue with the interpretation of micropulse lidar mask flags.

This code has helped remove erroneous cloud signal detected below 3 kilometers from the North Slope of Alaska micropulse lidar.

At the Southern Great Plains, the updated code has improved cloud detection below 3 kilometers from the micropulse lidar. The description of the lidar mask flag has been clarified to help identify valid data for the best estimate of clouds below 3 kilometers during periods with missing radar data.

It is recommended that people who downloaded the old ARMBECLDRAD data download the reprocessed data.

An ARMBE product assembles quantities that are both well observed by ARM over many years and are often used in model evaluation into one data set. These products consist of hourly averages and thus have temporal resolution comparable to a typical resolution used in climate model output.

Scientists can use the updated ARMBEATM and ARMBECLDRAD data sets now. Find more information about ARMBE data products on the ARMBE web page.

Feedback and use of the data are always welcomed. If you have questions/suggestions, please contact Yuying Zhang or Shaocheng Xie.

Users can access the updated ARMBEATM and ARMBECLDRAD data in the ARM Data Center. (Go here to create an account to download the data.)

To cite these data, use doi:10.5439/1333748 for ARMBEATM and doi:10.5439/1333228 for ARMBECLDRAD.

Katie Dorsey

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