Role of the North Atlantic in Indian Monsoon Droughts
Abstract
The forecast of Indian monsoon droughts has been predicated on the notion of a season-long rainfall deficit linked to warm anomalies in the equatorial Pacific. Here, we show that in fact nearly half of all droughts over the past century were sub-seasonal, and characterized by an abrupt decline in late-season rainfall. Furthermore, the potential driver of this class of droughts is a coherent cold anomaly in the North Atlantic Ocean. The vorticity forcing associated with this oceanic marker extends through the depth of the troposphere, and results in a wavetrain which curves towards the equator and extends to East-Asia. This upper-level response triggers an anomalous low-level anticyclonic circulation late in the season over India. This teleconnection from the midlatitudes offers an avenue for improved predictability of monsoon droughts.
Keywords
Cite
@article{arxiv.1911.10013,
title = {Role of the North Atlantic in Indian Monsoon Droughts},
author = {Pritam Borah and V. Venugopal and Jai Sukhatme and Pranesh Muddebihal and B. N. Goswami},
journal= {arXiv preprint arXiv:1911.10013},
year = {2019}
}
Comments
29 pages, 13 figures, 3 tables (Submitted July 2019)