Mesoscale Evaluation of AMPS Using AWARE Radar Observations of a Wind and Precipitation Event over the Ross Island Region of Antarctica

Wind and precipitation patterns over the Ross Ice Shelf of Antarctica are greatly influenced by the region’s complex topography. Some documentation of these features, particularly winds, has been accomplished with networks of surface weather observations. More comprehensive understanding of wind and precipitation patterns has been derived from the output of numerical simulations. The Antarctic Mesoscale Prediction System (AMPS) became operational in 2001 and has been the primary source of data for many of the studies that have examined wind and precipitation characteristics over the area. AMPS also serves as a critical forecast tool for operations of the U. S. Antarctic Program.

Evaluation of AMPS forecasts has been limited due to scarce meteorological observations, especially on the mesoscale. The present study addresses this gap with remote sensing observations collected during the Atmospheric Radiation Measurement (ARM) West Antarctic Radiation Experiment (AWARE) sponsored by the U.S. Department of Energy and National Science Foundation. AWARE occurred from 23 November 2015 to 5 January 2017 and made use of the second ARM mobile facility (i.e., AMF2). The primary AMF2 observing platform employed in this study is the X-band Scanning ARM Cloud Radar (XSACR), which was deployed on the southern tip of Ross Island near McMurdo Station. XSACR reflectivity and radial velocity observations over the Ross Island region are compared with AMPS output for a wind and precipitation event that spanned 16-20 January 2016. Notably, simulated radial velocity from AMPS compares favorably with observed radial velocities from XSACR. However, simulated AMPS reflectivity shows some significant differences from observed XSACR reflectivity.