Updated: New Cloud Radar and Sonde Products Available for TRACER, SAIL Campaigns

Published: 29 September 2022

Editor’s note (September 29, 2022): The end dates of the KAZRARSCL data for TRACER and SAIL have been updated below to reflect the availability of new data. The original announcement was published July 22, 2022.

Two plots from the TRACER Interpolated Sonde product show potential temperature (mostly in the 300 to 450 K range up to about 19 km) and quality check results on the potential temperature variable.
INTERPSONDE potential temperature output profiles are shown for October 7, 2021, during the TRacking Aerosol Convection interactions ExpeRiment (TRACER).

The Atmospheric Radiation Measurement (ARM) user facility has released cloud radar and sonde value-added products (VAPs) from two ongoing field campaigns.

ARM is conducting the TRacking Aerosol Convection interactions ExpeRiment (TRACER) near Houston, Texas, and the Surface Atmosphere Integrated Field Laboratory (SAIL) campaign near Crested Butte, Colorado. The Interpolated Sonde (INTERPSONDE) and Ka-Band ARM Zenith Radar Active Remote Sensing of CLouds (KAZRARSCL) VAPs are available for both campaigns.

INTERPSONDE transforms sounding data from weather balloon (sonde) launches into continuous daily files on a fixed time-height grid. Standard ARM sounding files provide atmospheric state data in one dimension of increasing time and height per sonde launch. Many applications require a quick estimate of the atmospheric state at higher time resolution.

To address this need, INTERPSONDE is available at 1-minute time resolution, and the grid extends from the surface to 332 levels (40 kilometers) to capture the full height of soundings. (Most soundings end between 25 and 30 kilometers, above which no data are provided.) Between soundings, the VAP linearly interpolates atmospheric state variables at each height level. In addition, INTERPSONDE data provide relative humidity scaled to microwave radiometer observations.

KAZRARSCL allows scientists to more easily use corrected observations from ARM’s vertically pointing cloud radar and to access hydrometeor masks and cloud boundaries for TRACER and SAIL.

Three images from the TRACER Ka-Band ARM Zenith Rader Remote Sensing of CLouds product show cloud boundaries (10 layers), best-estimate reflectivity (ranging from about -50 to 30 dBZ up to 15 km), and mean Doppler velocity (ranging from about -6.0 to 6 m/s to a limit of 18 km).
The three plots above illustrate the TRACER KAZRARSCL product. From top to bottom are time-versus-height images of cloud boundaries, best-estimate hydrometeor reflectivity, and dealiased mean Doppler velocity during TRACER on October 14, 2021.

The VAP combines KAZR, micropulse lidar, ceilometer, sounding, and microwave radiometer input observations, and it produces two datastreams. The arsclkazr1kollias datastream provides best-estimate radar reflectivities, mean Doppler velocities, spectral widths, and a significant detection mask in time and height. This datastream also provides up to 10 layers of cloud boundaries (cloud base and cloud top) and best-estimate cloud base height. The smaller arsclkazrbnd1kollias datastream provides only cloud boundaries and cloud base.

KAZRARSCL provides vertical profiles of cloud detections every four seconds from approximately 160 meters above ground level up to 18 kilometers, with 30-meter height resolution.

KAZRARSCL is available for SAIL from September 14, 2021, through July 31, 2022, and for TRACER from October 1, 2021, through July 31, 2022. Additional KAZRARSCL data are coming soon for both campaigns.

INTERPSONDE is available for SAIL from September 1, 2021, to about 10 days before the current date, and for TRACER from October 1, 2021, to about 10 days before the current date.

Both VAPs are available in daily files for the two campaigns.

More information about the VAPs can be found on the INTERPSONDE and KAZRARSCL web pages.

To ask questions, provide feedback, or report data problems, please contact Aifang Zhou or Scott Giangrande for INTERPSONDE, and Karen Johnson or Scott Giangrande for KAZRARSCL.

Access the data sets for INTERPSONDE and KAZRARSCL in the ARM Data Center. (Go here to create an account to download the data.)

INTERPSONDE data can be referenced as doi:10.5439/1095316.

To cite the KAZRARSCL data, please use doi:10.5439/1393437 for arsclkazr1kollias and doi:10.5439/1393438 for arsclkazrbnd1kollias.

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