Study of mean vertical motions over Gadanki (13.5°N, 79.2°E), a tropical station, using Indian MST radar
Study of mean vertical motions over Gadanki (13.5°N, 79.2°E), a tropical station, using Indian MST radar
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使用印度 MST 雷达研究热带站 Gadanki（北纬 13.5°，东经 79.2°）的平均垂直运动
DOI：
10.1029/2001rs002505
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发表时间：
2002
期刊：
影响因子：
1.6
通讯作者：
D. Rao
中科院分区：
文献类型：
--
作者：
V. Rao;M. Ratnam;D. Rao
[1]本文首次给出了在印度Gadanki（13.5°N，79.2°E）热带台站上空用MST雷达观测到的长期平均垂直速度。平均垂直速度剖面呈波浪状结构，垂直波长为1.6km，观测值平均为3 ~ 20 cm s-1。在季风和后季风季节，观测到更大的震级，可达20 cm s−1。从目前的研究中，一个有趣的功能，反转垂直速度从下向上5和10公里之间的季风季节，观察。这种长期平均垂直速度的向上运动被认为是由于在这个高度范围内风向的逆转，也是由于水平速度收敛，这是经常观察到在这个区域。在热带东风急流（TEJ）附近（约16公里）观察到另一个逆转，这是从下到上，始终显示最小垂直速度接近零。这种逆转可归因于与急流有关的不稳定性。在对流层低层6公里以下观测到大的负值，这是由于在该区域观测到的大的垂直风方差，表明重力波活动。
[1] Long-term mean vertical velocities observed by the Mesosphere-Stratosphere-Troposphere (MST) radar over a tropical station, Gadanki, India (13.5°N, 79.2°E), are presented for the first time in this paper. Profiles of mean vertical velocities show wave like structure with a vertical wavelength of ∼6 km, and the observed values range from 3 to 20 cm s−1 on average. During monsoon and postmonsoon seasons, larger magnitudes are observed up to 20 cm s−1. From the present study, an interesting feature, reversal in vertical velocities from downward to upward between 5 and 10 km during the monsoon season, is observed. This upward motion in long term averaged vertical velocity is thought to be due to reversal in wind direction around this height range and also due to horizontal velocity convergence, which is frequently observed over this region. One more reversal is observed near the Tropical Easterly Jet (TEJ) (around 16 km), which is from downward to upward and always showing minimum vertical velocities close to zero. This reversal can be attributed to instabilities associated with the jet streams. Large negative values are observed in the lower troposphere below 6 km, which are attributed to large vertical wind variances observed in this region indicating gravity wave activity.