东亚夏季平流层重力波的卫星高光谱红外观测与数值模拟研究

Convectively generated gravity waves significantly influence the middle atmospheric circulations, but the nature is not well known. The geolocation and seasonal variation of the gravity wave events and their sources are the basis of understanding and simulating the gravity wave effects. The Atmospheric InfraRed Sounder (AIRS) data can be used to simultaneously detect stratospheric gravity waves in the altitude range from 20 km to 65 km, which have vertical wavelengths larger than 15 km and horizontal wavelengths from 50 km to 1000 km, and conveciton in the same footprint. The focus of this study will be on the East Asian thunderstorm season, i.e., the time period from June to August each year, during which deep convection as well as convective waves occur frequently. Also characteristics of typhoon-generated stratospheric gravity waves will be investigated. First, a detection algorithm for gravity waves in AIRS data based on a variance filter algorithm for brightness temperatures at 4.3 μm and 15 μm will be presented. Second, an existing algorithm to detect deep convection in AIRS data will be optimized to be applicable in the study area. Then, the correlation relationship between the gravity events and deep convections will be analyzed. Finally, AIRS analysis results will be compared with the simulation results of the typhoon-generated grativy waves with the WRF model. This study is important to understand the evolution, distribution and pattern of stratospheic gravity waves. The developed methodologies can also be applied to process future Chinese Fengyun-3 hyperspectral infrared sounder measurements for stratospheric gravity wave analysis.

夏季对流性重力波对中层大气环流有显著影响。重力波活动及其激发源的地理分布是理解和模拟重力波效应的基础。卫星高光谱红外大气垂直探测器AIRS能够识别20-65km高度范围内垂直波长大于15km水平波长在50-1000km范围内的平行波扰动，并同步识别深对流。本研究关注东亚夏季平流层对流性重力波的发生频率，以及基于卫星观测与数值模拟的台风激发重力波特征的综合分析。首先，基于方差滤波法由AIRS在4.3微米的亮温直接识别重力波，并分析重力波的特征。其次，优化基于AIRS观测的阈值法识别深对流。随后，分析重力波与深对流之间的时空相关性。最后，选取典型的重力波事件，采用WRF开展模拟分析并与AIRS观测结果进行对比。预期得到10年以上AIRS平流层扰动的定量资料，并揭示平流层重力波的三维结构特征，对理解平流层重力波的分布规律以及与深对流之间的关系研究具有重要意义。

夏季对流性重力波对中层大气环流有显著影响。重力波活动及其激发源的地理分布是理解和模拟重力波效应的基础。卫星高光谱红外大气垂直探测器AIRS能够识别20-65km高度范围内垂直波长大于15km水平波长在50-1000km范围内的平行波扰动，并同步识别深对流。本研究关注于东亚夏季平流层对流性重力波的发生频率，以及基于卫星观测与数值模拟的台风激发重力波特征的综合分析。首先，基于方差滤波法由AIRS在4.3微米的亮温直接识别重力波，并分析了重力波的特征。其次，优化了基于AIRS观测的阈值法识别深对流。随后，分析了重力波与深对流之间的时空相关性。最后，选取典型的重力波事件，采用WRF开展模拟分析并与AIRS观测结果进行对比。得到了10年以上AIRS平流层扰动的定量资料，并揭示平流层重力波的三维结构特征，对理解平流层重力波的分布规律以及与深对流之间的关系研究具有重要意义。