Consistent response of Indian summer monsoon to Middle East dust in observations and simulations

Handle URI:
http://hdl.handle.net/10754/597838
Title:
Consistent response of Indian summer monsoon to Middle East dust in observations and simulations
Authors:
Jin, Q.; Wei, J.; Yang, Z.-L. ( 0000-0003-3030-0330 ) ; Pu, B.; Huang, J.
Abstract:
The response of the Indian summer monsoon (ISM) circulation and precipitation to Middle East dust aerosols on sub-seasonal timescales is studied using observations and the Weather Research and Forecasting model coupled with online chemistry (WRF-Chem). Satellite data show that the ISM rainfall in coastal southwest India, central and northern India, and Pakistan is closely associated with the Middle East dust aerosols. The physical mechanism behind this dust–ISM rainfall connection is examined through ensemble simulations with and without dust emissions. Each ensemble includes 16 members with various physical and chemical schemes to consider the model uncertainties in parameterizing short-wave radiation, the planetary boundary layer, and aerosol chemical mixing rules. Experiments show that dust aerosols increase rainfall by about 0.44mmday􀀀1 ( 10% of the climatology) in coastal southwest India, central and northern India, and north Pakistan, a pattern consistent with the observed relationship. The ensemble mean rainfall response over India shows a much stronger spatial correlation with the observed rainfall response than any other ensemble members. The largest modeling uncertainties are from the boundary layer schemes, followed by short-wave radiation schemes. In WRF-Chem, the dust aerosol optical depth (AOD) over the Middle East shows the strongest correlation with the ISM rainfall response when dust AOD leads rainfall response by about 11 days. Further analyses show that increased ISM rainfall is related to enhanced southwesterly monsoon flow and moisture transport from the Arabian Sea to the Indian subcontinent, which are associated with the development of an anomalous low-pressure system over the Arabian Sea, the southern Arabian Peninsula, and the Iranian Plateau due to dust-induced heating in the troposphere. The dust-induced heating in the mid-upper troposphere is mainly located in the Iranian Plateau rather than the Tibetan Plateau. This study demonstrates a thermodynamic mechanism that links remote desert dust emissions in the Middle East to ISM circulation and precipitation variability on subseasonal timescales, which may have implications for ISM rainfall forecasts.
Citation:
Jin Q, Wei J, Yang Z-L, Pu B, Huang J (2015) Consistent response of Indian summer monsoon to Middle East dust in observations and simulations. Atmos Chem Phys Discuss 15: 15571–15619. Available: http://dx.doi.org/10.5194/acpd-15-15571-2015.
Publisher:
Copernicus GmbH
Journal:
Atmospheric Chemistry and Physics Discussions
Issue Date:
11-Jun-2015
DOI:
10.5194/acpd-15-15571-2015
Type:
Article
ISSN:
1680-7375
Sponsors:
This research was supported by King Abdullah University of Science and Technology (KAUST). We wish to thank the Texas Advanced Computing Center for providing powerful computing resources. We also thank Patricia Bobeck and Alex Resovsky for proof-reading. Thanks to two reviewers for evaluating this paper.
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Full metadata record

DC FieldValue Language
dc.contributor.authorJin, Q.en
dc.contributor.authorWei, J.en
dc.contributor.authorYang, Z.-L.en
dc.contributor.authorPu, B.en
dc.contributor.authorHuang, J.en
dc.date.accessioned2016-02-25T12:57:34Zen
dc.date.available2016-02-25T12:57:34Zen
dc.date.issued2015-06-11en
dc.identifier.citationJin Q, Wei J, Yang Z-L, Pu B, Huang J (2015) Consistent response of Indian summer monsoon to Middle East dust in observations and simulations. Atmos Chem Phys Discuss 15: 15571–15619. Available: http://dx.doi.org/10.5194/acpd-15-15571-2015.en
dc.identifier.issn1680-7375en
dc.identifier.doi10.5194/acpd-15-15571-2015en
dc.identifier.urihttp://hdl.handle.net/10754/597838en
dc.description.abstractThe response of the Indian summer monsoon (ISM) circulation and precipitation to Middle East dust aerosols on sub-seasonal timescales is studied using observations and the Weather Research and Forecasting model coupled with online chemistry (WRF-Chem). Satellite data show that the ISM rainfall in coastal southwest India, central and northern India, and Pakistan is closely associated with the Middle East dust aerosols. The physical mechanism behind this dust–ISM rainfall connection is examined through ensemble simulations with and without dust emissions. Each ensemble includes 16 members with various physical and chemical schemes to consider the model uncertainties in parameterizing short-wave radiation, the planetary boundary layer, and aerosol chemical mixing rules. Experiments show that dust aerosols increase rainfall by about 0.44mmday􀀀1 ( 10% of the climatology) in coastal southwest India, central and northern India, and north Pakistan, a pattern consistent with the observed relationship. The ensemble mean rainfall response over India shows a much stronger spatial correlation with the observed rainfall response than any other ensemble members. The largest modeling uncertainties are from the boundary layer schemes, followed by short-wave radiation schemes. In WRF-Chem, the dust aerosol optical depth (AOD) over the Middle East shows the strongest correlation with the ISM rainfall response when dust AOD leads rainfall response by about 11 days. Further analyses show that increased ISM rainfall is related to enhanced southwesterly monsoon flow and moisture transport from the Arabian Sea to the Indian subcontinent, which are associated with the development of an anomalous low-pressure system over the Arabian Sea, the southern Arabian Peninsula, and the Iranian Plateau due to dust-induced heating in the troposphere. The dust-induced heating in the mid-upper troposphere is mainly located in the Iranian Plateau rather than the Tibetan Plateau. This study demonstrates a thermodynamic mechanism that links remote desert dust emissions in the Middle East to ISM circulation and precipitation variability on subseasonal timescales, which may have implications for ISM rainfall forecasts.en
dc.description.sponsorshipThis research was supported by King Abdullah University of Science and Technology (KAUST). We wish to thank the Texas Advanced Computing Center for providing powerful computing resources. We also thank Patricia Bobeck and Alex Resovsky for proof-reading. Thanks to two reviewers for evaluating this paper.en
dc.publisherCopernicus GmbHen
dc.rights.urihttp://creativecommons.org/licenses/by/3.0/en
dc.titleConsistent response of Indian summer monsoon to Middle East dust in observations and simulationsen
dc.typeArticleen
dc.identifier.journalAtmospheric Chemistry and Physics Discussionsen
dc.contributor.institutionDepartment of Geological Sciences, University of Texas at Austin, 1 University Station C1100, Austin, Texas 78712, USAen
dc.contributor.institutionKey Laboratory for Semi-Arid Climate Change of the Ministry of Education, College of Atmospheric Sciences, Lanzhou University, Lanzhou, Gansu 730000, Chinaen
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