A Case Study of Observed and Modeled Barrier Flow in the Denmark Strait in May 2015

Abstract

esoscale barrier jets in the Denmark Strait are common in winter months and have the capability to influence open ocean convection. This paper presents the first detailed observational study of a summertime (May 21, 2015) barrier wind event in the Denmark Strait using dropsondes and observations from an airborne Doppler Wind Lidar (DWL). The DWL profiles agree well with dropsonde observations and show a vertically narrow (~250-400 m) barrier jet of 23 to 28 m s-1 near the Greenland coast that broadens (~300-1000 m) and strengthens further off coast. In addition, we analyze otherwise identical regional high resolution Weather Research and Forecasting (WRF) model simulations of the event at four horizontal grid spacings (5, 10, 25, and 50 km), two vertical resolutions (40 and 60 levels), and two planetary boundary layer (PBL) parameterizations (MYNN2.5 and UW) to determine what model configurations best simulate the observed jet structure. Comparison of the WRF simulations with wind observations from satellites, dropsondes, and the airborne DWL scans indicate that the combination of both high horizontal resolution (5 km) and vertical resolution (60 levels) best captures observed barrier jet structure and speeds as well as the observed cloud field, including some convective clouds. Both WRF PBL schemes produced reasonable barrier jets with the UW scheme slightly out performing the MYNN2.5 scheme. However, further investigation at high horizontal and vertical resolution is needed to determine the impact of the WRF PBL scheme on surface energy budget terms, particularly in the high-latitude maritime environment around Greenland.