Movement, drivers and bimodality of the South Asian High
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 observation...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2016-11-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/16/14755/2016/acp-16-14755-2016.pdf |
| _version_ | 1818382379155193856 |
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| author | M. Nützel M. Dameris H. Garny |
| author_facet | M. Nützel M. Dameris H. Garny |
| author_sort | M. Nützel |
| collection | DOAJ |
| description | 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. |
| first_indexed | 2024-12-14T02:49:32Z |
| format | Article |
| id | doaj.art-104547573b1848d59fe9aa344dfbba59 |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-12-14T02:49:32Z |
| publishDate | 2016-11-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-104547573b1848d59fe9aa344dfbba592022-12-21T23:19:48ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242016-11-0116147551477410.5194/acp-16-14755-2016Movement, drivers and bimodality of the South Asian HighM. Nützel0M. Dameris1H. Garny2Deutsches Zentrum für Luft- und Raumfahrt, Institut für Physik der Atmosphäre, Oberpfaffenhofen, GermanyDeutsches Zentrum für Luft- und Raumfahrt, Institut für Physik der Atmosphäre, Oberpfaffenhofen, GermanyDeutsches Zentrum für Luft- und Raumfahrt, Institut für Physik der Atmosphäre, Oberpfaffenhofen, GermanyThe 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.https://www.atmos-chem-phys.net/16/14755/2016/acp-16-14755-2016.pdf |
| spellingShingle | M. Nützel M. Dameris H. Garny Movement, drivers and bimodality of the South Asian High Atmospheric Chemistry and Physics |
| title | Movement, drivers and bimodality of the South Asian High |
| title_full | Movement, drivers and bimodality of the South Asian High |
| title_fullStr | Movement, drivers and bimodality of the South Asian High |
| title_full_unstemmed | Movement, drivers and bimodality of the South Asian High |
| title_short | Movement, drivers and bimodality of the South Asian High |
| title_sort | movement drivers and bimodality of the south asian high |
| url | https://www.atmos-chem-phys.net/16/14755/2016/acp-16-14755-2016.pdf |
| work_keys_str_mv | AT mnutzel movementdriversandbimodalityofthesouthasianhigh AT mdameris movementdriversandbimodalityofthesouthasianhigh AT hgarny movementdriversandbimodalityofthesouthasianhigh |