Horizontal winds derived from the polar mesospheric cloud images as observed by the CIPS instrument on the AIM satellite
Horizontal winds derived from the polar mesospheric cloud images as observed by the CIPS instrument on the AIM satellite
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由 AIM 卫星上的 CIPS 仪器观测到的极地中层云图像得出的水平风
DOI：
10.1002/2014jd022813
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
C. Randall
中科院分区：
文献类型：
--
作者：
P. Rong;J. Yue;J. Russell;J. Lumpe;J. Gong;D. Wu;C. Randall
利用云模式匹配技术对云成像和粒子大小仪器（CIPS）拍摄的极地中层云（PMC）图像进行处理，以反演中层顶区域的风速。对CIPS的测量结果进行分析，以检测从一个轨道到下一个轨道重复但位置发生位移的模式;位移提供了风速的测量。模式匹配是通过将CIPS数据重新定位到经纬度网格来实现的，其中网格框大小在两个方向上都强制为约5 km。在被称为经度约500 km ×纬度400 km的“框架”的地理区域内搜索相关模式。导出的速度直方图表明，东风占主导地位，平均纬向风为−20至−15 m/s。平均纬向风总体较小，但在夏末，直方图显示向极风约为20-30米/秒。在固定的地理位置上，CIPS云的连续轨道上的变化也被检查。统计结果表明，约86%的对在连续轨道上经历了小于50%的平均云量变化，这表明了适度的变化。还发现，在一个固定位置的两个连续的轨道之间的云结构的相关性一般是穷人。这些发现表明，云的模式是受风平流，但云补丁的大小比发生的运动更广泛。云空洞被发现更有可能保持在相同的地理位置。
A cloud pattern matching technique is applied to polar mesospheric cloud (PMC) images taken by the Cloud Imaging and Particle Size instrument (CIPS) to infer the wind velocities in the mesopause region. CIPS measurements are analyzed to detect patterns that repeat from one orbit to the next but are displaced in location; the displacement provides a measure of the wind velocity. Pattern matching is achieved by resampling the CIPS data to longitude and latitude grids with the grid‐box size forced at ~5 km in both directions. The correlated patterns are searched within a geographic region referred to as a “frame” of ~500 km in longitude × 400 km in latitude. The histograms of the derived velocities indicate that easterly winds prevail, with a mean zonal wind of −20 to −15 m/s. Mean meridional winds are overall small, but in late summer the histogram indicated a poleward wind of ~20–30 m/s. The variability of CIPS cloud albedo on consecutive orbits is also examined at fixed geolocations. The statistical results suggest that ~86% of pairs underwent mean cloud albedo variation of < 50% on consecutive orbits, suggesting a moderate change. It is also found that the correlation of the cloud structures between two consecutive orbits at a fixed location is generally poor. These findings suggest that cloud patterns are subject to wind advection, but the cloud patches are more extended in size than the movement that occurs. Cloud voids are found to be more likely to remain at the same geolocations.