Indian monsoon derailed by a North Atlantic wavetrain
Borah, P.J.; Venugopal, V.; Sukhatme, J.; Muddebihal, P.; Goswami, B.N. (2020). Indian monsoon derailed by a North Atlantic wavetrain. Science (Wash.) 370(6522): 1335-1338. https://dx.doi.org/10.1126/science.aay6043
In: Science (Washington). American Association for the Advancement of Science: New York, N.Y. ISSN 0036-8075; e-ISSN 1095-9203, meer
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| Auteurs | | Top |
- Borah, P.J.
- Venugopal, V.
- Sukhatme, J.
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- Muddebihal, P.
- Goswami, B.N.
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| Abstract |
The forecast of Indian monsoon droughts has been predicated on the notion of a season-long rainfall deficit linked to a warm equatorial Pacific. Here we show that nearly half of all droughts over the past century differ from this paradigm in that they (i) occur when Pacific temperatures are near-neutral and (ii) are subseasonal phenomena, characterized by an abrupt decline in late-season rainfall. This severe subseasonal rainfall deficit can be associated with a Rossby wave from mid-latitudes. Specifically, we find that the interaction of upper-level winds with an episodic North Atlantic vorticity anomaly results in a wavetrain that curves toward East Asia, disrupting the monsoon. This atmospheric teleconnection offers an avenue for improved predictability of droughts, especially in the absence of telltale signatures in the Pacific. |
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