WACR-ARSCL Evaluation Data Available for MARCUS Field Campaign

Published: 20 May 2019
wacr-arscl value-added product data images
From top to bottom, these images from the MARCUS WACR-ARSCL VAP show best-estimate reflectivity, non-ship-corrected mean Doppler velocity, and ship-corrected mean Doppler velocity for November 28, 2017.

A value-added product (VAP) that combines observations from the marine version of the 95 GHz W-Band ARM Cloud Radar (WACR) and other ARM mobile instruments now provides datastreams from the Measurements of Aerosols, Radiation, and Clouds over the Southern Ocean (MARCUS) field campaign.

Evaluation data for the WACR-Active Remote Sensing of Clouds (WACR-ARSCL) VAP are now available for MARCUS from October 19, 2017, through March 24, 2018. During MARCUS, the second ARM Mobile Facility collected atmospheric observations aboard the Aurora Australis supply vessel as it traveled between Australia and Antarctica.

WACR-ARSCL provides cloud boundaries and best-estimate time-height fields of radar moments. WACR observations are corrected for velocity aliasing, which occurs when the radar target’s velocity exceeds the maximum velocity the radar can measure, and then significant detection masks are produced to screen out radar background noise. The corrected WACR measurements are combined with observations from the micropulse lidar, ceilometer, balloon-borne radiosondes, rain gauge, and microwave radiometer, and low-level clutter is identified and removed.

This process results in two datastreams. The MARCUS datastreams for WACR-ARSCL are: mararsclwacr1kolliasM1.c1, which contains best-estimate time-height fields of radar moments plus cloud base and cloud layer boundaries; and mararsclwacrbnd1kolliasM1.c1, a subset datastream that includes only cloud boundaries and cloud base estimates.

Users can access the data set from the ARM Data Center. (Go here to create an account to download the data.) Ship-corrected datastreams—mararsclwacr1kolliasshpM1.c1 and mararsclwacrbnd1kolliasshpM1.c1—are also available. The primary impact of the ship corrections is to adjust the mean Doppler velocity for ship heave (upward/downward motion).

Note—Because of issues with the ship navigation data, the mararsclwacr1kolliasM1.c1 and mararsclwacrbnd1kolliasM1.c1 datastreams should be used in place of the ship-corrected datastreams for the following time periods:

  • December 20, 2017 (113000 Coordinated Universal Time), to December 21, 2017 (041500)
  • February 16, 2018 (063000 to 163000).

More information on WACR-ARSCL is available on the VAP web page. During this evaluation period, please send any product-related comments and suggestions to Meng Wang, data product developer. Such feedback will assist in improving the product before its full release.

# # #

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