Air sea conditions facilitate a transformation of the positive Indian Ocean Dipole with distinct east pole characteristics into an extreme event
The Indian Ocean Dipole (IOD) is one of the dominant interannual variabilities in the Indian Ocean (IO), and an extreme IOD, in particular, has dramatic effects on the weather, agriculture, and ecosystem around it. Therefore, the formation of an extreme IOD has been a worldwide research focus. Among...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2023-03-01
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| Series: | Frontiers in Marine Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fmars.2023.1106130/full |
| _version_ | 1811162698286628864 |
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| author | Zhi Li Zhi Li Zhi Li Zecheng Xu Zecheng Xu Yunxia Zheng Yue Fang Yue Fang |
| author_facet | Zhi Li Zhi Li Zhi Li Zecheng Xu Zecheng Xu Yunxia Zheng Yue Fang Yue Fang |
| author_sort | Zhi Li |
| collection | DOAJ |
| description | The Indian Ocean Dipole (IOD) is one of the dominant interannual variabilities in the Indian Ocean (IO), and an extreme IOD, in particular, has dramatic effects on the weather, agriculture, and ecosystem around it. Therefore, the formation of an extreme IOD has been a worldwide research focus. Among 13 positive IOD (PIOD) events, two type-east and two type-comparable PIODs developed into extreme events during the 1960–2020 period. This investigation focuses on the cause of the formation of the type-east extreme PIOD, as previous studies have discussed the origin of the type-comparable extreme PIOD. Composite analysis showed that, as an entity, the strong East Asian and Australian monsoon (EAAM) may result in an evident easterly wind anomaly around the Indonesian region of the Marine Continent during May to August of the years when type-east PIODs occurred. The easterly wind anomaly associated with the EAAM was stronger in the extreme IOD group, whereas it was relatively weak in the regular group. The difference in the easterly wind anomaly between the extreme and regular groups could result in a vertical motion anomaly by enhancing the anomalous westward current. The stronger vertical motion created an upwelling in the deep-layer cold water, resulting in a more distinct difference in the vertical temperature gradient. All these conditions promoted the transformation of the type-east PIODs that occurred in 1961 and 1994 into extreme events and are indicative of the importance of vertical advection terms in the formation of type-east extreme PIODs. This study reveals the cause of the formation of type-east extreme PIODs, which will be helpful in understanding IOD diversity. |
| first_indexed | 2024-04-10T06:33:28Z |
| format | Article |
| id | doaj.art-e4ef4951be4e427ea20c8f47248fe1c6 |
| institution | Directory Open Access Journal |
| issn | 2296-7745 |
| language | English |
| last_indexed | 2024-04-10T06:33:28Z |
| publishDate | 2023-03-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Marine Science |
| spelling | doaj.art-e4ef4951be4e427ea20c8f47248fe1c62023-03-01T05:20:01ZengFrontiers Media S.A.Frontiers in Marine Science2296-77452023-03-011010.3389/fmars.2023.11061301106130Air sea conditions facilitate a transformation of the positive Indian Ocean Dipole with distinct east pole characteristics into an extreme eventZhi Li0Zhi Li1Zhi Li2Zecheng Xu3Zecheng Xu4Yunxia Zheng5Yue Fang6Yue Fang7First Institute of Oceanography, Ministry of Natural Resources and Laboratory for Regional Oceanography and Numerical Modeling, Laoshan Laboratory, Qingdao, ChinaShanghai Typhoon Institute, China Meteorological Administration, Shanghai, ChinaShandong Key Laboratory of Marine Science and Numerical Modeling, Qingdao, ChinaFirst Institute of Oceanography, Ministry of Natural Resources and Laboratory for Regional Oceanography and Numerical Modeling, Laoshan Laboratory, Qingdao, ChinaShanghai Typhoon Institute, China Meteorological Administration, Shanghai, ChinaShanghai Typhoon Institute, China Meteorological Administration, Shanghai, ChinaFirst Institute of Oceanography, Ministry of Natural Resources and Laboratory for Regional Oceanography and Numerical Modeling, Laoshan Laboratory, Qingdao, ChinaShandong Key Laboratory of Marine Science and Numerical Modeling, Qingdao, ChinaThe Indian Ocean Dipole (IOD) is one of the dominant interannual variabilities in the Indian Ocean (IO), and an extreme IOD, in particular, has dramatic effects on the weather, agriculture, and ecosystem around it. Therefore, the formation of an extreme IOD has been a worldwide research focus. Among 13 positive IOD (PIOD) events, two type-east and two type-comparable PIODs developed into extreme events during the 1960–2020 period. This investigation focuses on the cause of the formation of the type-east extreme PIOD, as previous studies have discussed the origin of the type-comparable extreme PIOD. Composite analysis showed that, as an entity, the strong East Asian and Australian monsoon (EAAM) may result in an evident easterly wind anomaly around the Indonesian region of the Marine Continent during May to August of the years when type-east PIODs occurred. The easterly wind anomaly associated with the EAAM was stronger in the extreme IOD group, whereas it was relatively weak in the regular group. The difference in the easterly wind anomaly between the extreme and regular groups could result in a vertical motion anomaly by enhancing the anomalous westward current. The stronger vertical motion created an upwelling in the deep-layer cold water, resulting in a more distinct difference in the vertical temperature gradient. All these conditions promoted the transformation of the type-east PIODs that occurred in 1961 and 1994 into extreme events and are indicative of the importance of vertical advection terms in the formation of type-east extreme PIODs. This study reveals the cause of the formation of type-east extreme PIODs, which will be helpful in understanding IOD diversity.https://www.frontiersin.org/articles/10.3389/fmars.2023.1106130/fullIndian Ocean Dipole (IOD)extreme event analysisAsian–Australian monsooneasterly wind anomalyheat budget analysis |
| spellingShingle | Zhi Li Zhi Li Zhi Li Zecheng Xu Zecheng Xu Yunxia Zheng Yue Fang Yue Fang Air sea conditions facilitate a transformation of the positive Indian Ocean Dipole with distinct east pole characteristics into an extreme event Frontiers in Marine Science Indian Ocean Dipole (IOD) extreme event analysis Asian–Australian monsoon easterly wind anomaly heat budget analysis |
| title | Air sea conditions facilitate a transformation of the positive Indian Ocean Dipole with distinct east pole characteristics into an extreme event |
| title_full | Air sea conditions facilitate a transformation of the positive Indian Ocean Dipole with distinct east pole characteristics into an extreme event |
| title_fullStr | Air sea conditions facilitate a transformation of the positive Indian Ocean Dipole with distinct east pole characteristics into an extreme event |
| title_full_unstemmed | Air sea conditions facilitate a transformation of the positive Indian Ocean Dipole with distinct east pole characteristics into an extreme event |
| title_short | Air sea conditions facilitate a transformation of the positive Indian Ocean Dipole with distinct east pole characteristics into an extreme event |
| title_sort | air sea conditions facilitate a transformation of the positive indian ocean dipole with distinct east pole characteristics into an extreme event |
| topic | Indian Ocean Dipole (IOD) extreme event analysis Asian–Australian monsoon easterly wind anomaly heat budget analysis |
| url | https://www.frontiersin.org/articles/10.3389/fmars.2023.1106130/full |
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