Abstract
During the summer monsoon season, the authors observe a wave train that stretches from the northern Arabian Peninsula and Caspian Sea to the Indo-Gangetic plains along the foothills of the Himalaya and extending further east of the Tibetan Plateau. The trend analysis between 1979 and 2018 with NCEP–NCAR reanalysis data show that the diabatic heating flux (averaged over 1000 to 500 hPa) tends to decrease significantly over the Caspian Sea and its surrounding regions. In addition, the sea level pressure is increasing by ~0.1 hPa yr−1 over the Caspian Sea, forming a high-pressure divergent center over there. The divergent center is collocated with an anticyclonic circulation trend at 850 hPa over the Caspian Sea. This decreasing diabatic heating flux modulates the local atmospheric circulation by increasing the surface pressure around the center of divergence, which further facilitates a wave train to propagate towards South and East Asia. This wave train transports the moisture fluxes at 925 hPa from the Caspian Sea, southeastward towards the South and East Asian monsoon region.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 381-389 |
| Number of pages | 9 |
| Journal | Atmospheric and Oceanic Science Letters |
| Volume | 13 |
| Issue number | 5 |
| DOIs | |
| State | Published - Sep 2 2020 |
Bibliographical note
Funding Information:This work was jointly supported by the Ministry of Science and Technology of China [grant number 2016YFA0600604], the National Natural Science Foundation of China [grant numbers 41950410756 and 41675061], and the Key Research Program of Frontier Sciences, Chinese Academy of Sciences [grant number QYZDY-SSW-DQC024].
Publisher Copyright:
© 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
Keywords
- Caspian Sea
- diabatic heating
- Indian summer monsoon
- Moisture transport
- wave train
ASJC Scopus subject areas
- Oceanography
- Atmospheric Science