基于OH全天空气辉成像仪观测的中国低纬地区的重力波传播统计特征

利用位于海南富克(19.5°N,109.1°E)和广西桂平(23.4°N,110.1°E)两个台站两年多的OH全天空气辉成像仪观测数据,对中国低纬地区的重力波传播统计特征进行了研究.从富克和桂平的气辉成像观测中, 分别提取了65和86个重力波事件.研究结果表明,观测水平波长,观测周期和水平相速度分别集中分布在10~35 km, 4~14 min和20~90 m·s-1范围.重力波传播方向,在夏季表现出很强的东北方向传播.然而,在冬季主要沿东南和西南方向传播. 同时,结合流星雷达风场观测和TIMED/SABER卫星的温度数据,也发现在中层-低热层中传播的大多数重力波表现为耗散传播.且低层-中层大气中背景风场的滤波作用和多普勒频移可能对纬向方向传播的重力波产生的各向异性起到重要的调制作用.然而,经向方向传播的重力波产生的各向异性可能同时被低层大气中波源的非均匀分布以及潮汐变化所影响.

Statistical characteristics analysis of atmospheric gravity waves with OH all-sky airglow imagers at low-latitude region of China

To study the statistical characteristic of low-latitude atmospheric gravity waves in the mesosphere and lower thermosphere in southern China, we carried out long-term (the observation at Fuke during March of 2010 to July of 2012 and at Guiping during September of 2012 to November of 2013) observation with OH all-sky airglow imager at Fuke (19.5°N, 109.1°E), Hainan, and Guiping (23.4°N, 110.1°E), Guangxi. We extracted 65 and 86 gravity wave events from OH imagers observation at Fuke and Guiping, respectively. Observed horizontal wavelength, observed period, and horizontal phase velocity of gravity waves at Fuke and Guiping are mainly distributed in the range of 10~35 km, 4~14 min, and 20~90 m·s^-1, respectively. The propagation directions of the gravity waves are dominantly northeast during summer. However, southwestward and southeastward propagation are dominant during winter. Combining with wind measurements from the Doppler meteor radar and temperature data from SABER on board TIMED satellite, we also found that most of gravity waves propagated evanescently. The statistical results show that the background wind filtering and Doppler shifting may play an important role in controlling the anisotropy of AGWs in the zonal direction. However, the anisotropy of AGWs propagation in the meridional direction may be affected simultaneously by the non-uniform distribution of wave sources and tides in the lower atmosphere.