Tropical Cyclone Activities Over the Western North Pacific in Summer 2020: Transition From Silence in July to Unusually Active in August
In the summer of 2020, tropical cyclone (TC) activities experienced a contrastive transition over the western North Pacific (WNP), from silence in July to unusually active in August. Furthermore, the generation location of TCs was further northwestward in August 2020, resulting in more typhoons land...
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| Language: | English |
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Frontiers Media S.A.
2022-02-01
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| Series: | Frontiers in Earth Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/feart.2022.843990/full |
| _version_ | 1818987698160926720 |
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| author | Zhensong Gong Yunyun Liu Yunyun Liu Zeng-Zhen Hu Ping Liang |
| author_facet | Zhensong Gong Yunyun Liu Yunyun Liu Zeng-Zhen Hu Ping Liang |
| author_sort | Zhensong Gong |
| collection | DOAJ |
| description | In the summer of 2020, tropical cyclone (TC) activities experienced a contrastive transition over the western North Pacific (WNP), from silence in July to unusually active in August. Furthermore, the generation location of TCs was further northwestward in August 2020, resulting in more typhoons landing, and three TCs successively moving northward, which is rare in history. Based on diagnoses with the total genesis potential index (GPI) in July and August 2020, it is suggested that the variation of mid-tropospheric relative humidity and upward convective motion is the major factor for the transition of TC genesis in summer 2020, while the changes of SST, low-level vorticity, and vertical wind shear anomalies played a secondary role. The exceptional variation of the Madden–Julian Oscillation (MJO) activity from July to August 2020 contributed to the transition of the environmental conditions over WNP. In July 2020, MJO was restricted in the Indian Ocean, thus generating an anomalous low-level anticyclone over WNP that intensified the WNP subtropical high. While in early August, MJO propagated eastward to enhance convective activities over the South China Sea and the Philippine Sea, favorable to TC genesis. Thus, MJO activity is a potential predictability source for intraseasonal variation of TC genesis anomalies in WNP. |
| first_indexed | 2024-12-20T19:10:49Z |
| format | Article |
| id | doaj.art-8fd7dbaf0b0544c09143a181744ea7e8 |
| institution | Directory Open Access Journal |
| issn | 2296-6463 |
| language | English |
| last_indexed | 2024-12-20T19:10:49Z |
| publishDate | 2022-02-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Earth Science |
| spelling | doaj.art-8fd7dbaf0b0544c09143a181744ea7e82022-12-21T19:29:13ZengFrontiers Media S.A.Frontiers in Earth Science2296-64632022-02-011010.3389/feart.2022.843990843990Tropical Cyclone Activities Over the Western North Pacific in Summer 2020: Transition From Silence in July to Unusually Active in AugustZhensong Gong0Yunyun Liu1Yunyun Liu2Zeng-Zhen Hu3Ping Liang4CMA Climate Studies Key Laboratory, National Climate Center, China Meteorological Administration, Beijing, ChinaCMA Climate Studies Key Laboratory, National Climate Center, China Meteorological Administration, Beijing, ChinaKey Laboratory of Meteorological Disaster, Ministry of Education and Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science and Technology, Nanjing, ChinaClimate Prediction Center, NCEP/NOAA, College Park, MD, United StatesKey Laboratory of Cities’ Mitigation and Adaptation to Climate Change in Shanghai, Shanghai Regional Climate Center, China Meteorological Administration, Shanghai, ChinaIn the summer of 2020, tropical cyclone (TC) activities experienced a contrastive transition over the western North Pacific (WNP), from silence in July to unusually active in August. Furthermore, the generation location of TCs was further northwestward in August 2020, resulting in more typhoons landing, and three TCs successively moving northward, which is rare in history. Based on diagnoses with the total genesis potential index (GPI) in July and August 2020, it is suggested that the variation of mid-tropospheric relative humidity and upward convective motion is the major factor for the transition of TC genesis in summer 2020, while the changes of SST, low-level vorticity, and vertical wind shear anomalies played a secondary role. The exceptional variation of the Madden–Julian Oscillation (MJO) activity from July to August 2020 contributed to the transition of the environmental conditions over WNP. In July 2020, MJO was restricted in the Indian Ocean, thus generating an anomalous low-level anticyclone over WNP that intensified the WNP subtropical high. While in early August, MJO propagated eastward to enhance convective activities over the South China Sea and the Philippine Sea, favorable to TC genesis. Thus, MJO activity is a potential predictability source for intraseasonal variation of TC genesis anomalies in WNP.https://www.frontiersin.org/articles/10.3389/feart.2022.843990/fulltropical cyclone genesis in 2020 summerwestern North Pacifictransition from silence in July to active in Augustgenesis potential indexMadden-Julian oscillation |
| spellingShingle | Zhensong Gong Yunyun Liu Yunyun Liu Zeng-Zhen Hu Ping Liang Tropical Cyclone Activities Over the Western North Pacific in Summer 2020: Transition From Silence in July to Unusually Active in August Frontiers in Earth Science tropical cyclone genesis in 2020 summer western North Pacific transition from silence in July to active in August genesis potential index Madden-Julian oscillation |
| title | Tropical Cyclone Activities Over the Western North Pacific in Summer 2020: Transition From Silence in July to Unusually Active in August |
| title_full | Tropical Cyclone Activities Over the Western North Pacific in Summer 2020: Transition From Silence in July to Unusually Active in August |
| title_fullStr | Tropical Cyclone Activities Over the Western North Pacific in Summer 2020: Transition From Silence in July to Unusually Active in August |
| title_full_unstemmed | Tropical Cyclone Activities Over the Western North Pacific in Summer 2020: Transition From Silence in July to Unusually Active in August |
| title_short | Tropical Cyclone Activities Over the Western North Pacific in Summer 2020: Transition From Silence in July to Unusually Active in August |
| title_sort | tropical cyclone activities over the western north pacific in summer 2020 transition from silence in july to unusually active in august |
| topic | tropical cyclone genesis in 2020 summer western North Pacific transition from silence in July to active in August genesis potential index Madden-Julian oscillation |
| url | https://www.frontiersin.org/articles/10.3389/feart.2022.843990/full |
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