Abstract

Mesospheric cooling during Stratospheric Sudden Warming (SSW) has been observed by instruments and simulated by various models. While TIME-GCM successfully simulates the cooling effect, the simulated cooling layer thickness is larger than observed. Gravity waves are considered as the primary cont... Show moreMesospheric cooling during Stratospheric Sudden Warming (SSW) has been observed by instruments and simulated by various models. While TIME-GCM successfully simulates the cooling effect, the simulated cooling layer thickness is larger than observed. Gravity waves are considered as the primary contributor to the mesospheric cooling and the lower thermosphere warming during SSW through changing the meridional circulation. The aforementioned discrepancies could be caused by the unrealistic gravity wave parameterization. To improve the parameterization for TIME-GCM, we use a gravity wave parameterization model (the Lindzen scheme) to investigate how the mesospheric and lower-thermospheric forcing response to different gravity wave parameters. The background temperature and wind profiles are taken from the NCAR TIME-GCM simulation of the 2008 SSW in Northern Hemisphere. By varying gravity wave spectrum shape, horizontal wavelength, and amplitude as the input to the Lindzen scheme, the mesospheric forcing during the 2008 SSW will be quantified and the gravity wave impacts on the meridional circulation will be assessed. Show less