Revisiting the strong and weak ENSO teleconnection impacts using a high-resolution atmospheric model

Ahmad Dogar, Muhammad Mubashar and Almazroui, Mansour (2022) Revisiting the strong and weak ENSO teleconnection impacts using a high-resolution atmospheric model. Atmospheric Environment, 270. ISSN 1352-2310

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Abstract

To evaluate the performance of a high-resolution atmospheric model (HiRAM) and to improve our understanding of the climatic impacts of ENSO forcing and associated teleconnections, we analyzed AMIP-style HiRAM simulations conducted effectively at 25 km grid spacing. To better assess HiRAM response to ENSO climate variability; we categorized it into strong and weak El Niño/La Niña episodes. The HiRAM model reproduced the impacts of strong ENSO over global scale very well, however, it underestimated ENSO teleconnection patterns and associated changes over regional scale (e.g., MENA and South Asia), especially following weak ENSO that could be attributed to model weak response to circulation changes such as Pacific North American (PNA) and North Atlantic Oscillation (NAO). Moreover, our results emphasize that ENSO impacts are relatively stronger over the Inter-Tropical Convergence Zone (ITCZ) compared to extra-tropics and high-latitude regions. The positive phase of ENSO causes weakening in rainfall over the African tropical rain-belt, parts of South and Southeast Asia. Both the reanalysis and HiRAM results reveal that ENSO-induced negative (positive) NAO-like response and associated changes over Southern Europe and North Africa vary significantly following the increased intensity of El Niño (La Niña). We further found that the ENSO magnitude significantly impacts Hadley and Walker circulations. The El Niño phase of ENSO overall strengthens the Hadley Cell, and the reverse is true for the La Niña phase. This ENSO-induced strengthening and weakening of Hadley Cell induce significant impact over South Asian and African convective regions through modification of the ITCZ circulation system.

Item Type:	Article
Additional Information:	Funding Information: We would like to thank the editor and two anonymous reviewers whose constructive suggestions and comments significantly improved the manuscript. An updated description of the latest version of the model used in this study as well as previous model versions is available at https://www.gfdl.noaa.gov/atmospheric-model/. Publisher Copyright: © 2021 Elsevier Ltd
Uncontrolled Keywords:	enso,la nina,hadley circulation,itcz,mena,monsoon system,nao,environmental science(all),atmospheric science ,/dk/atira/pure/subjectarea/asjc/2300
Faculty \ School:	Faculty of Science > School of Environmental Sciences
Related URLs:	http://www.scopus.com/inward/record.url?...
Depositing User:	LivePure Connector
Date Deposited:	02 Dec 2021 02:50
Last Modified:	30 Nov 2022 01:38
URI:	https://ueaeprints.uea.ac.uk/id/eprint/82465
DOI:	10.1016/j.atmosenv.2021.118866

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