Tropical Indian Ocean Mediates ENSO Influence Over Central Southwest Asia During the Wet Season

Muhammad Adnan Abid, Moetasim Ashfaq, Fred Kucharski, Katherine J. Evans, Mansour Almazroui

Research output: Contribution to journalArticlepeer-review

28 Scopus citations

Abstract

El Niño–Southern Oscillation (ENSO) modulates wet season (November–April) precipitation over Central Southwest Asia (CSWA), however, intraseasonal characteristics of its influence are largely unknown, which can be important for its subseasonal to seasonal hydroclimate predictability. Here we show that the ENSO-CSWA teleconnection varies intraseasonally and is a combination of direct and indirect positive influences. The direct influence is through a Rossby wave-like pattern in the tail months. The indirect influence is through an atmospheric dipole of diabatic heating anomalies in the tropical Indian Ocean (TIO) as a result of ENSO-forced response, which also generates a Rossby wave-like forcing and persists throughout the wet season. ENSO exerts its strongest influence when both direct and indirect modes are in phase, while the relationship breaks down when the two modes are out of phase. The atmospheric teleconnection through the atmospheric diabatic heating anomalies in the TIO is reproducible in numerical simulations.

Original languageEnglish
Article numbere2020GL089308
JournalGeophysical Research Letters
Volume47
Issue number18
DOIs
StatePublished - Sep 28 2020

Funding

We obtained ERA5 reanalysis from https://cds.climate.copernicus.eu/ website, GPCP precipitation from https://psl.noaa.gov/data/gridded/data.gpcp.html website, and NCEP/NCAR reanalysis from https://psl.noaa.gov/data/gridded/ website. The details regarding the SPEEDY model are available at https://www.ictp.it/research/esp/models/speedy.aspx website. The SPEEDY model experiment data, used in this study, are available at http://clima-dods.ictp.it/Users/mabid/GRL_Abidetal/ website. This manuscript has been coauthored by employees of Oak Ridge National Laboratory, managed by UT Battelle, LLC, under contract DE‐AC05‐00OR22725 with the U.S. Department of Energy. The publisher, by accepting the article for publication, acknowledges that the U.S. Government retains a nonexclusive, paid‐up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for U.S. Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( http://energy.gov/downloads/doe-public-access-plan ). M. A. A. would like to acknowledge Earth System Physics Section of ICTP and Centre of Excellence for Climate Change Research (CECCR) for their support. M. A. and K. J. E. are supported by the U.S. Air Force Numerical Weather Modeling Program. M. A. A. would also like to thank KAU high performance computing center (https://hpc.kau.edu.sa) for providing AZIZ supercomputer resources. We also thank the two anonymous reviewers for their insightful comments. M. A. A. would like to acknowledge Earth System Physics Section of ICTP and Centre of Excellence for Climate Change Research (CECCR) for their support. M. A. and K. J. E. are supported by the U.S. Air Force Numerical Weather Modeling Program. M. A. A. would also like to thank KAU high performance computing center ( https://hpc.kau.edu.sa ) for providing AZIZ supercomputer resources. We also thank the two anonymous reviewers for their insightful comments.

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