WRF simulations of convectively generated gravity waves during TWP-ICE

Description

All convective clouds emit gravity waves (GWs). As they propagate, the GWs emitted by clouds displace air parcels vertically, possibly producing further cloud. These waves also transport momentum and energy large distances from the site of their generation, exerting a stress on the atmosphere wherever they dissipate. The larger project examines the part played by convectively generated GWs in the formation of cirrus and in the subgrid-scale momentum transport and associated large-scale stresses imposed on the troposphere and stratosphere. The work reported here focuses specifically on the characteristics of the convectively generated GWs simulated by high resolution simulations using WRF for the period during the Tropical Warm Pool-International Cloud Experiment (TWP-ICE).

Characteristics of the high-frequency GWs simulated by WRF simulations are consistent with our previous reports using radiosonde observations. During the break monsoon period, the diurnal variation of activity of the high-frequency GWs in the stratosphere shows a clear peak in the late afternoon. This peak is pronounced over land, consistent with the afternoon continental convection. In comparison, the peak wave activity over water has significantly lower magnitude and occurs in the early morning hours. This characteristic is consistent with shallower maritime convection. Furthermore, spectral characteristics of the high-frequency GWs, which were not resolved accurately by radiosonde observations, can be derived from model simulations and will be presented here.