Intraseasonal Air–Sea Interaction Over the Southeastern Indian Ocean and its Impact on Indian Summer Monsoon
The weak monsoon rainfall simulation in the CMIP6 models calls for further process understanding about the Indian summer monsoon (ISM), especially the intraseasonal variabilities. Here, the remote forcing from the Southern Hemisphere on the Indian summer monsoon is examined. Over the southeastern In...
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Frontiers Media S.A.
2022-07-01
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| Series: | Frontiers in Marine Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fmars.2022.921585/full |
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| author | Ze Meng Lei Zhou Lei Zhou Jianhuang Qin Baosheng Li |
| author_facet | Ze Meng Lei Zhou Lei Zhou Jianhuang Qin Baosheng Li |
| author_sort | Ze Meng |
| collection | DOAJ |
| description | The weak monsoon rainfall simulation in the CMIP6 models calls for further process understanding about the Indian summer monsoon (ISM), especially the intraseasonal variabilities. Here, the remote forcing from the Southern Hemisphere on the Indian summer monsoon is examined. Over the southeastern Indian Ocean (SEIO), intraseasonal warm SST anomalies can induce low-level southeasterly wind anomalies and accelerate the background southeasterly wind. According to the mechanism of Wind-Evaporation-SST (WES) feedback, the wind acceleration gives rise to the positive anomalies of surface latent heat flux (LHF). The intraseasonal wind anomalies propagate equatorward along with the background southeasterlies; the positive LHF increases the moist static energy over the equator. As a result, deep convections are reinforced over tropics, which strengthen the northward-propagating monsoon intraseasonal oscillations. During boreal summer, the northward intraseasonal oscillation prompts enhanced rainfall events over the monsoon region. Current results indicate the inter-hemispheric impacts as an inevitable contributor to the heavy precipitation during ISM in the Northern Hemisphere. In CMIP6, the models with better SST simulations over SEIO can have stronger equatorial rainfall and more realistic northward propagation. The unsatisfactory simulations of CMIP6 are associated with the defective ocean–atmosphere interaction over SEIO, and one clue is the feeble variances of intraseasonal oceanic signals over SEIO, which is far from the observation. This research offers a new perspective on the chronic dry monsoon bias in the Northern Hemisphere; the cross-equatorial process and the bias of intraseasonal oceanic variation over SEIO deserve further attention in the coupled models. |
| first_indexed | 2024-04-12T09:05:56Z |
| format | Article |
| id | doaj.art-585aed0936ff4fffb4a26d8a334fe2f4 |
| institution | Directory Open Access Journal |
| issn | 2296-7745 |
| language | English |
| last_indexed | 2024-04-12T09:05:56Z |
| publishDate | 2022-07-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Marine Science |
| spelling | doaj.art-585aed0936ff4fffb4a26d8a334fe2f42022-12-22T03:39:05ZengFrontiers Media S.A.Frontiers in Marine Science2296-77452022-07-01910.3389/fmars.2022.921585921585Intraseasonal Air–Sea Interaction Over the Southeastern Indian Ocean and its Impact on Indian Summer MonsoonZe Meng0Lei Zhou1Lei Zhou2Jianhuang Qin3Baosheng Li4School of Oceanography, Shanghai Jiao Tong University, Shanghai, ChinaSchool of Oceanography, Shanghai Jiao Tong University, Shanghai, ChinaSouthern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, ChinaCollege of Oceanography, Hohai University, Nanjing, ChinaState Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, ChinaThe weak monsoon rainfall simulation in the CMIP6 models calls for further process understanding about the Indian summer monsoon (ISM), especially the intraseasonal variabilities. Here, the remote forcing from the Southern Hemisphere on the Indian summer monsoon is examined. Over the southeastern Indian Ocean (SEIO), intraseasonal warm SST anomalies can induce low-level southeasterly wind anomalies and accelerate the background southeasterly wind. According to the mechanism of Wind-Evaporation-SST (WES) feedback, the wind acceleration gives rise to the positive anomalies of surface latent heat flux (LHF). The intraseasonal wind anomalies propagate equatorward along with the background southeasterlies; the positive LHF increases the moist static energy over the equator. As a result, deep convections are reinforced over tropics, which strengthen the northward-propagating monsoon intraseasonal oscillations. During boreal summer, the northward intraseasonal oscillation prompts enhanced rainfall events over the monsoon region. Current results indicate the inter-hemispheric impacts as an inevitable contributor to the heavy precipitation during ISM in the Northern Hemisphere. In CMIP6, the models with better SST simulations over SEIO can have stronger equatorial rainfall and more realistic northward propagation. The unsatisfactory simulations of CMIP6 are associated with the defective ocean–atmosphere interaction over SEIO, and one clue is the feeble variances of intraseasonal oceanic signals over SEIO, which is far from the observation. This research offers a new perspective on the chronic dry monsoon bias in the Northern Hemisphere; the cross-equatorial process and the bias of intraseasonal oceanic variation over SEIO deserve further attention in the coupled models.https://www.frontiersin.org/articles/10.3389/fmars.2022.921585/fullSoutheastern Indian Oceanocean–atmosphere interactionintraseasonal variability (ISV)Indian summer monsoon (ISM)CMIP6 |
| spellingShingle | Ze Meng Lei Zhou Lei Zhou Jianhuang Qin Baosheng Li Intraseasonal Air–Sea Interaction Over the Southeastern Indian Ocean and its Impact on Indian Summer Monsoon Frontiers in Marine Science Southeastern Indian Ocean ocean–atmosphere interaction intraseasonal variability (ISV) Indian summer monsoon (ISM) CMIP6 |
| title | Intraseasonal Air–Sea Interaction Over the Southeastern Indian Ocean and its Impact on Indian Summer Monsoon |
| title_full | Intraseasonal Air–Sea Interaction Over the Southeastern Indian Ocean and its Impact on Indian Summer Monsoon |
| title_fullStr | Intraseasonal Air–Sea Interaction Over the Southeastern Indian Ocean and its Impact on Indian Summer Monsoon |
| title_full_unstemmed | Intraseasonal Air–Sea Interaction Over the Southeastern Indian Ocean and its Impact on Indian Summer Monsoon |
| title_short | Intraseasonal Air–Sea Interaction Over the Southeastern Indian Ocean and its Impact on Indian Summer Monsoon |
| title_sort | intraseasonal air sea interaction over the southeastern indian ocean and its impact on indian summer monsoon |
| topic | Southeastern Indian Ocean ocean–atmosphere interaction intraseasonal variability (ISV) Indian summer monsoon (ISM) CMIP6 |
| url | https://www.frontiersin.org/articles/10.3389/fmars.2022.921585/full |
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