利用COSMIC RO数据分析青藏高原平流层重力波活动特征

本文利用2006年5月至2013年4月COSMIC干温廓线数据,提取了青藏高原地区大气重力波势能,以此研究了青藏高原大气重力波势能的分布频率模型和大气重力波活动的时空变化特征,并进一步分析了高原大气重力波活动与高原地形、风速和高原大陆热辐射之间的相关性.青藏高原地区大气重力波势能的分布频率服从对数生长分布;青藏高原地区大气重力波在16~18 km和28~31 km高度较活跃,而在20~26 km高度较平静;高原大陆边缘各季节重力波活动均较活跃,而高原大陆上空大气重力波活动呈明显季节性变化,其在冬春季节较活跃,在夏秋季节较平静;2010年冬季青藏高原大气重力波活动异常平静;各季节整个高原上空大气重力波活跃度有随大气高度升高而降低的趋势,高原上低层大气重力波向高层传播会发生耗散作用.地形与风速是影响青藏高原大气重力波活动的重要因素.地形主要影响平流层底部的重力波活动;纬向风比经向风对该地区平流层大气重力波活动的影响大,纬向风总体上会促进高原大气重力波活动.青藏高原大陆热辐射对高原大气的加热作用是导致青藏高原大气重力波活动呈季节性变化的重要因素.

Analysis of the active characteristics of stratosphere gravity waves over the Qinghai-Tibetan Plateau using COSMIC radio occultation data

Using GPS RO dry temperature profiles obtained by COSMIC mission from May 2006 to April 2013, we obtain the potential energy (E_p) of the stratosphere gravity waves (GW) over the Qinghai-Tibetan Plateau (TP). We have investigated frequency distribution probability model and spatial-temporal variation characteristics of the GW over TP. We further analyzed the correlation between the GW over TP and the TP terrain, the GW over TP and the surface wind speed, the GW over TP and thermal radiation. The frequency distribution of the GW over TP is loglogistic distribution; GW over TP were highly active in 16~18 km and 28~31 km height but calm in 20~26 km height; GW activities over margin of TP continental were active in each season, while GW activities over TP continental showed a seasonal change, they were more active in the winter and calmer in the summer; GW activities over TP were unusually quiet in the winter 2010; each season GW activities over TP decrease with an increasing height, and wave dissipation may happen when GW propagate from bottom to upper atmosphere. Topography and wind speed are important factors affecting the activities of the GW over TP. Topography affects activities of the GW over TP in bottom of the stratosphere. Zonal wind has a greater influence in the GW over TP than the meridional wind. The GW activities over TP will be primarily promoted by zonal wind. Heating effect of thermal radiation to the atmosphere on the TP continental is an important factor leading to seasonal change of the GW activities over TP.