Modeling the Southern Hemisphere winter circulation using realistic zonal mean gravity wave information in the lower atmosphere

5. JACOBI, CH., F. LILIENTHAL, T. SCHMIDT, A. DE LA TORRE

Wissenschaftliche Mitteilungen, Rep. Inst. Meteorol. Univ. Leipzig

University Leipzig

Lugar: Leipzig; Año: 2016; p. 37 - 46

A mechanistic global circulation model is used to simulate the mesosphericand lower thermospheric circulation during austral winter. The model includesa gravity wave (GW) parameterization that is initiated by prescribed GW parameters inthe troposphere. In standard configuration, these waves are described by a simple distributionwith large amplitudes in the winter hemisphere and small ones in summer.Here we replace this distribution by a more realistic one, which is based on observationsof potential GW energy using GPS radio occultations, but which is normalized tothe same global mean amplitude. The model experiment shows that this new gravitywave distribution leads to weaker zonal winds in the mesosphere, a downward shift ofthe meridional poleward mesospheric wind jet, enhanced downwelling in the mid-tohigh-latitude winter mesosphere and warming of the polar stratopause.