Study of Gravity Wave Variations in the Polar Regions Using ECMWF T799

Gravity wave is one of the key elements that affects the atmospheric variability and determines the circulation pattern of the middle and upper atmosphere. However, the gravity wave source distributions and variations are not fully understood due to observational and modeling difficulty of gravity waves. Recent ECMWF T799 simulation results with horizontal resolutions of ~25km have the potential of resolving gravity waves down to the mesoscale. In this study, we first validate these resolved gravity waves in ECMWF T799 by comparing them to lidar observations in Antarctica. The seasonal variations of gravity waves in ECMWF T799 show good agreements with lidar observations. We then investigate gravity wave variations as related to the rapid change of the wind during the 2009 Stratospheric Sudden Warming in NH from the troposphere to the upper stratosphere. The causes of these gravity wave variations will be addressed.