An Intercomparison of Schemes to Identify, Track, and Predict Convective Planetary Boundary Layer Phenomena

Low altitude aircraft can conserve energy through static soaring by flying in regions of ascent within convective planetary boundary layer (PBL) circulations. Wind shear in the PBL can be used for dynamic soaring to also gain energy. To achieve this, it is necessary to accurately predict the three-dimensional wind within the PBL. A variety of schemes of varying complexities are available for the prediction of PBL winds. Results of an intercomparison of PBL nowcasting schemes during a field campaign from August 12-19, 2014 will be presented. Data from the Texas Tech Ka-band mobile radars and the WSR-88D radars in Denver and Cheyenne were used as inputs to the nowcasting schemes. A pseudo-w product to identify quasi-linear PBL structures was derived from reflectivity data obtained from both the TTU Ka-band and WSR-88D radars. A dual-Doppler synthesis of three-dimensional wind was available from the TTU Ka-band radars. The nowcasting schemes include persistence, advection of the entire field based on motion vectors from a RAP/VAD synthesis and a correlation-based approach to identify motion estimates in successive images, and the w2segmotion algorithm in the Warning Decision Support System—Integrated Information suite. Skill scores from the various approaches will be presented with the goal of achieving sufficient forecast skill while minimizing the computational resources needed to produce an adequate forecast.