| Using the temperature profiles retrieved from the Mars Climate Sounder (MCS) instrument onboard Mars Reconnaissance Orbiter (MRO) satellite between November2006and April2013, we studied the seasonal and inter-annual variability of Quasi-Stationary Planetary Waves (QSPWs) in the Martian middle atmosphere. The paper focuses on the global structure, seasonal and inter-annual variability of the stationary planetary waves with zonal wavenumber s=1and s=2for full four mars years.The QSPW amplitudes in the Southern Hemisphere (SH) high latitudes are significant stronger than those in the Northern Hemisphere (NH). Seasonal variation with maximum amplitude near winter solstice of each hemisphere is clearly seen. The vertical structure of the QSPW in temperature shows double-layer feature with the lower peak near50Pa and the higher peak near1Pa. The QSPW in geo-potential height, derived from temperature data, is clearly maximized in the region between two temperature peaks. The maximum amplitude of s=1QSPW is-8-10K in temperature and～1km in geo-potential height in the SH high latitudes. The maximum amplitude at the SH high latitudes in Mars Year (MY)31is-2K stronger than those in other MYs, suggesting a clear inter-annual variability. We compare the satellite results with those obtained from the Mars Climate Database (MCD) simulation version5.0; and a reasonable agreement was found. The MCD simulation further suggested that the variability of dust might partially contribute to the inter-annual variability of QSPW amplitude. In dusty environments such intensity amplitude quasi-stationary planetary waves are relatively strong, while in the less dust environment, quasi-stationary planetary wave amplitude is relatively weak. On the other hand, the QSPW also have a significance influence on the horizontal distribution of dust. This work represents the most complete observations.of QSPWs in the recent years. Our observational results could further improve the Martian atmosphere model simulation. |
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