Statistical study of short-period gravity waves in OH and OI nightglow images at two separated sites
Statistical study of short-period gravity waves in OH and OI nightglow images at two separated sites
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DOI：
10.1029/2002jd002795
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发表时间：
2003-11-13
影响因子：
4.4
通讯作者：
Tsuda, T
中科院分区：
文献类型：
--
作者：
Ejiri, MK;Shiokawa, K;Tsuda, T
[1]利用近红外OH波段（720 - 910 nm）和OI（557.7 nm）线的气辉图像，我们研究了短周期重力波的季节、纬度和当地时间的变化。这些图像是在1998年10月至1999年10月期间在日本两个相距1200公里的地点，即陆别（北纬43.5度，东经143.8度）和滋贺木（北纬34.9度，东经136.1度）获得的。我们的分析主要集中在波长小于40公里，主相速度类似于20 - 50米/秒的小尺度重力波。陆别和志贺木的OH和OI波发生率均显着高于60%，夏季值略大。从晚上到午夜，发生率增加。在水平波长、传播方向和相速度方面没有明显的本地时间依赖性。在夏季，两个地点的传播方向都是向北或东北方向。然而，在冬季，陆别的传播方向通常是向西（西北、西和西南），而志贺木的传播方向仅为西南方向。根据若奈（45.4 ° N，141.7 ° E）和山川（31.2 ° N，130.6 ° E）中频雷达同时观测的风场，讨论了多普勒和热导管、风滤波以及重力波从低层大气传播到中层顶区气辉高度的源分布等可能的影响。
[1] Using airglow images of the near-infrared OH band (720 - 910 nm) and OI (557.7 nm) line, we investigated seasonal, latitudinal, and local time variations of short-period gravity waves. The images were obtained at two locations in Japan that are similar to 1200 km apart, Rikubetsu (43.5 degreesN, 143.8 degreesE) and Shigaraki (34.9 degreesN, 136.1 degreesE), between October 1998 and October 1999. Our analysis has focused on small-scale gravity waves with wavelengths less than 40 km and dominant phase speeds of similar to 20 - 50 m/s. Wave occurrences for both OH and OI at Rikubetsu and Shigaraki are significantly higher than 60%, with a slightly larger value in summer. The occurrences increase from evening to midnight. There are no obvious local time dependencies in horizontal wavelength, propagation direction, and phase speed. The propagation directions in summer are either northward or northeastward at both locations. However, in winter the propagation directions at Rikubetsu are generally westward ( NW, W, and SW), whereas those at Shigaraki are only southwestward. From simultaneous wind observation by the MF radars at Wakkanai (45.4 degreesN, 141.7 degreesE) and Yamagawa (31.2 degreesN, 130.6 degreesE), we discuss possible influences of Doppler and thermal ducting, wind filtering, and source distribution of gravity waves propagating from the lower atmosphere to the airglow heights in the mesopause region.