Modeling Mountain Wave Dynamics from 0-200 km in Large Domains at High Resolution

A new compressible model employing a stretched mesh enables simulations of mountain wave (MW) dynamics, interactions, instabilities, and secondary gravity-wave (SGW) generation, using high resolution where needed, in large domains. Simulations described here were performed for strong airflow over the Southern Andes and weaker airflow over New Zealand during winter, when sustained eastward winds allow MW penetration directly into the mesosphere and lower thermosphere (MLT). Strong forcing over the Andes and a rapidly-increasing eastward flow with increasing altitude enable strong MW growth into the mesosphere and lower thermosphere (MLT). Rapid eastward wind reductions above yield strong MW breaking at 85 and 120 km, with accompanying tidal interactions, modulated momentum deposition, and SGW generation. A simulation of similar MW behavior observed over New Zealand during the DEEPWAVE program revealed very similar MLT MW dynamics. This talk will compare and contrast these two events and their implications for mean forcing, GW/tidal interactions, and SGW generation in the MLT.