Relationship between Azores High and Indian summer monsoon

Abstract A dominant mode of interannual variability of Indian summer monsoon rainfall shows west-east dipole pattern with above normal rainfall towards west and central India and subdued rainfall towards the east and northeast India, and is related to the vigorous Azores High. The vigorous Azores Hi...

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Main Author: Ramesh Kumar Yadav
Format: Article
Language:English
Published: Nature Portfolio 2021-04-01
Series:npj Climate and Atmospheric Science
Online Access:https://doi.org/10.1038/s41612-021-00180-z
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author Ramesh Kumar Yadav
author_facet Ramesh Kumar Yadav
author_sort Ramesh Kumar Yadav
collection DOAJ
description Abstract A dominant mode of interannual variability of Indian summer monsoon rainfall shows west-east dipole pattern with above normal rainfall towards west and central India and subdued rainfall towards the east and northeast India, and is related to the vigorous Azores High. The vigorous Azores High is accompanied by enhanced subsidence resulting in well-built widespread upper-troposphere convergence. This forms the meridional vorticity dipole consisting of anomalous cyclonic and anti-cyclonic circulation at 30°N and 50°N, respectively, and boosts the Rossby wave source. The cascading down Rossby wave train imposes successive negative, positive and negative Geopotential height (GPH) anomalies over north Mediterranean, northwest and northeast of India, respectively. The negative GPH anomaly at the north Mediterranean increases the Asian jet towards the Caspian Sea, strengthening the monsoon circulation through the ‘silk-road’ pattern. While, the dipole GPH anomaly north of India shift the Tibetan High westwards, triggering monsoon activity towards the west.
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spelling doaj.art-435f46e054674f3ebc60f15dfa69fecf2022-12-21T21:52:39ZengNature Portfolionpj Climate and Atmospheric Science2397-37222021-04-01411910.1038/s41612-021-00180-zRelationship between Azores High and Indian summer monsoonRamesh Kumar Yadav0Indian Institute of Tropical Meteorology, PashanAbstract A dominant mode of interannual variability of Indian summer monsoon rainfall shows west-east dipole pattern with above normal rainfall towards west and central India and subdued rainfall towards the east and northeast India, and is related to the vigorous Azores High. The vigorous Azores High is accompanied by enhanced subsidence resulting in well-built widespread upper-troposphere convergence. This forms the meridional vorticity dipole consisting of anomalous cyclonic and anti-cyclonic circulation at 30°N and 50°N, respectively, and boosts the Rossby wave source. The cascading down Rossby wave train imposes successive negative, positive and negative Geopotential height (GPH) anomalies over north Mediterranean, northwest and northeast of India, respectively. The negative GPH anomaly at the north Mediterranean increases the Asian jet towards the Caspian Sea, strengthening the monsoon circulation through the ‘silk-road’ pattern. While, the dipole GPH anomaly north of India shift the Tibetan High westwards, triggering monsoon activity towards the west.https://doi.org/10.1038/s41612-021-00180-z
spellingShingle Ramesh Kumar Yadav
Relationship between Azores High and Indian summer monsoon
npj Climate and Atmospheric Science
title Relationship between Azores High and Indian summer monsoon
title_full Relationship between Azores High and Indian summer monsoon
title_fullStr Relationship between Azores High and Indian summer monsoon
title_full_unstemmed Relationship between Azores High and Indian summer monsoon
title_short Relationship between Azores High and Indian summer monsoon
title_sort relationship between azores high and indian summer monsoon
url https://doi.org/10.1038/s41612-021-00180-z
work_keys_str_mv AT rameshkumaryadav relationshipbetweenazoreshighandindiansummermonsoon