从这两个开创性论文[Koteswaram TEJ][1]和[Raghavan K TEJ 1973][2](可用收费,复制-[热带东风急流的起源][3]),在上层存在一个反气旋在印度次大陆,也被称为西藏反气旋。热带东风急流(TEJ)被认为是与西藏反气旋。西藏反气旋出现在对流层上部(100 - 150 hPa)。[![在这里输入图像描述][4]][4]在上面的图片来自NCEP NCAR再分析资料在6月到9月的气候学100 hPa位势高度提出,可以清楚地看到西藏反气旋的更广泛的季风反气旋。所以西藏反气旋的位置是按照季节性变化。在冬天西藏反气旋进一步南(大约10 N)和在夏季它移动到温暖的纬度。低水平的反气旋倾斜朝赤道方向在北方夏季和冬季向极。然而上层反气旋的水平倾斜向极在所有季节。Koteswaran和Raghavan计算反气旋的阻碍的纬向分量和似乎没有比较高层东风与印度夏季风((ISM) [5])。 But there appears to be strong comparison with the winds derived from thermal gradient over the Tibetan Plateau. **So it appears that the winds are originating due to thermal reasons alone**. The TEJ is to a large extent influenced by the temperature distribution in the upper levels as a result of vertical motion associated with ISM. The Tibetan plateau comes under the influence of both sensible and latent heat and leading to the formation of a [surface heat low][6] [![enter image description here][7]][7] Shown here is the sea level pressure climatology of the June-September period and one can clearly see the heat low over the elevated Tibetan plateau. Given that the climatology of the surface pressure during the June through September period indicates that the mean value is around 500 hPa it might be helpful to look at the temperature of the 500 hPa climatology. [![enter image description here][8]][8] [![enter image description here][9]][9] Once again one can clearly that the 500 hPa temperature surface(500 hPa is the average surface pressure over the Tibetan plateau over the June September period) that the Tibetan plateau provides for an elevated heat source. Krishnamurti in the book [Monsoon Models][10] offers a detailed explanation - the southerly outflow of the subtropical jet provides a mechanism where eddy kinetic energy is converted into kinetic energy of the mean flow and all this happens above 250 hPa. Stratospheric easterly winds penetrate downwards into the northern branch of the TEJ. Above all the conversion of available potential energy into kinetic energy above 250 hPa in the region of increasing pressure gradient caused by the proximity of the Tibetan anticyclone as well as the Coriolis force convert the diabatic heat into kinetic energy of the TEJ. In recent years due to the decrease in the temperature contrast between the land and sea over the Indian subcontinent the TEJ has shown a decreasing trend and there are several studies that illustrate this trend as well. [1]: http://www.tellusa.net/index.php/tellusa/article/viewFile/9220/10832 [2]: http://link.springer.com/article/10.1007/BF00876576 [3]: http://www.tropmet.res.in/~lip/Publication/RR-pdf/RR-06.pdf [4]: https://i.stack.imgur.com/0pfR1.gif [5]: //www.hoelymoley.com/questions/4427/climatology-of-the-indian-summer-monsoon-a-modern-consensus/4436#4436 [6]: https://en.wikipedia.org/wiki/Thermal_low [7]: https://i.stack.imgur.com/5wQ2N.gif [8]: https://i.stack.imgur.com/ivs7o.gif [9]: https://i.stack.imgur.com/F0ThE.gif [10]: https://www.amazon.com/Monsoons-Jay-S-Fein/dp/0471874167