Impact of WSR-88D Scanning Strategies on Severe Storm Algorithms

Abstract

The operational meteorological community generally recognizes that the greater spatial and temporal resolution of WSR-88D volume coverage pattern (VCP) 11 is preferable to VCP 21 when using algorithms to identify severe storm characteristics. The coarser vertical sampling of storms with VCP 21 likely produces less accurate results. An experiment was conducted to investigate the comparative effects of VCPs 11 and 21. Since VCP 21 is nearly a subset of VCP 11, the appropriate elevation angles were deleted from two VCP 11 datasets to produce proxy datasets for VCP 21 (called VCP 22). Various WSR-88D operational algorithms and National Severe Storms Laboratory prototype severe storm algorithms were run on the VCP 11 and VCP 21/22 datasets. At heights above 5° elevation angle, where VCP 21/22 had missing elevation angles relative to VCP 11, the majority of algorithm parameters had different values at least 50%?70% of the time. Therefore, this study confirms that VCP 11?not VCP 21?should be used in those convective storm situations where there is a contribution to critical warning parameters from elevation angles greater than 5°.