Pacific decadal oscillation causes fewer near-equatorial cyclones in the North Indian Ocean

Roose, S. ORCID: https://orcid.org/0000-0002-6444-4837, Ajayamohan, R. S., Ray, P., Xie, S.-P., Sabeerali, C. T., Mohapatra, M., Taraphdar, S., Mohanakumar, K. and Rajeevan, M. (2023) Pacific decadal oscillation causes fewer near-equatorial cyclones in the North Indian Ocean. Nature Communications, 14. 5099. ISSN 2041-1723 doi: 10.1038/s41467-023-40642-x

Abstract/Summary

Tropical cyclones do not form easily near the equator but can intensify rapidly, leaving little time for preparation. We investigate the number of near-equatorial (originating between 5°N and 11°N) tropical cyclones over the north Indian Ocean during post-monsoon season (October to December) over the past 60 years. The study reveals a marked 43% decline in the number of such cyclones in recent decades (1981--2010) compared to earlier (1951--1980). Here, we show this decline in tropical cyclone frequency is primarily due to the weakened low-level vorticity modulated by the Pacific Decadal Oscillation (PDO) and increased vertical wind shear. In the presence of low-latitude basin-wide warming and a favorable phase of the PDO, both the intensity and frequency of such cyclones are expected to increase. Such dramatic and unique changes in tropical cyclonic activity due to the interplay between natural variability and climate change call for appropriate planning and mitigation strategies.

Item Type	Article
URI	https://centaur.reading.ac.uk/id/eprint/130678
Identification Number/DOI	10.1038/s41467-023-40642-x
Refereed	Yes
Divisions	No Reading authors. Back catalogue items Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Download/View statistics	View download statistics for this item