Movement, drivers and bimodality of the South Asian High

Nützel, Matthias and Dameris, Martin and Garny, Hella (2016) Movement, drivers and bimodality of the South Asian High. Atmospheric Chemistry and Physics (16), pp. 14755-14774. Copernicus Publications. doi: 10.5194/acp-16-14755-2016. ISSN 1680-7316.

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Abstract

Using seven reanalyses, we study the movement and drivers of the upper tropospheric–lower stratospheric anticyclone (AC) that forms during the Asian summer monsoon and is debated to be an important pathway for air masses to the stratosphere. We find that the distribution of the AC's centre position, and especially the so-called bimodality, largely depends on the reanalysis. Furthermore, we can connect shifts of the AC to precipitation and convection anomalies over India and the western Pacific.

Item URL in elib:

https://elib.dlr.de/108422/

Document Type:

Article

Additional Information:

Abstract. The South Asian High (SAH) is an important component of the summer monsoon system in Asia. In this study we investigate the location and drivers of the SAH at 100 hPa during the boreal summers of 1979 to 2014 on interannual, seasonal and synoptic timescales using seven reanalyses and observational data. Our comparison of the different reanalyses focuses especially on the bimodality of the SAH, i.e. the two preferred modes of the SAH centre location: the Iranian Plateau to the west and the Tibetan Plateau to the east. We find that only the National Centers for Environmental Prediction–National Center of Atmospheric Research (NCEP–NCAR) reanalysis shows a clear bimodal structure of the SAH centre distribution with respect to daily and pentad (5 day) mean data. Furthermore, the distribution of the SAH centre location is highly variable from year to year. As in simple model studies, which connect the SAH to heating in the tropics, we find that the mean seasonal cycle of the SAH and its centre are dominated by the expansion of convection in the South Asian region (70–130° E  ×  15–30° N) on the south-eastern border of the SAH. A composite analysis of precipitation and outgoing long-wave radiation data with respect to the location of the SAH centre reveals that a more westward (eastward) location of the SAH is related to stronger (weaker) convection and rainfall over India and weaker (stronger) precipitation over the western Pacific.

Title:

Movement, drivers and bimodality of the South Asian High

Authors:

Authors	Institution or Email of Authors	Author's ORCID iD
Nützel, Matthias	DLR, IPA	UNSPECIFIED
Dameris, Martin	DLR, IPA	UNSPECIFIED
Garny, Hella	DLR, IPA	UNSPECIFIED

Date:

25 November 2016

Journal or Publication Title:

Atmospheric Chemistry and Physics

Refereed publication:

Yes

Open Access:

Yes

Gold Open Access:

Yes

In SCOPUS:

Yes

In ISI Web of Science:

Yes

DOI:

10.5194/acp-16-14755-2016

Page Range:

pp. 14755-14774

Publisher:

Copernicus Publications

ISSN:

1680-7316

Status:

Published

Keywords:

SAH, bimodality, movement, drivers, Asian summer monsoon

HGF - Research field:

Aeronautics, Space and Transport

HGF - Program:

Space

HGF - Program Themes:

Earth Observation

DLR - Research area:

Raumfahrt

DLR - Program:

R EO - Earth Observation

DLR - Research theme (Project):

R - Atmospheric and climate research

Location:

Oberpfaffenhofen

Institutes and Institutions:

Institute of Atmospheric Physics > Earth System Modelling

Deposited By:

Nützel, Matthias

Deposited On:

28 Nov 2016 12:56

Last Modified:

20 Jun 2021 15:48

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