Comparative analysis of two flow decomposition approaches and their applications in diagnosing water vapor in extreme precipitation events over Xinjiang province, China
Water vapor flux divergence under the terrain-following coordinate system is decomposed into slow and fast manifolds with the adoption of the Barnes filter method and the synoptic approach based on the Helmholtz theorem in this study. The performances and applications of both methods are evaluated i...
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Frontiers Media S.A.
2022-08-01
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| Series: | Frontiers in Earth Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/feart.2022.847317/full |
| _version_ | 1817995247023554560 |
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| author | Jie Cao Shuping Ma Shuping Ma Lingkun Ran |
| author_facet | Jie Cao Shuping Ma Shuping Ma Lingkun Ran |
| author_sort | Jie Cao |
| collection | DOAJ |
| description | Water vapor flux divergence under the terrain-following coordinate system is decomposed into slow and fast manifolds with the adoption of the Barnes filter method and the synoptic approach based on the Helmholtz theorem in this study. The performances and applications of both methods are evaluated in precipitating events over the Xinjiang province in China when traditional analysis fails to capture the evolutions of extreme precipitations caused by multi-scale systems and complicated terrains. A blizzard with a short duration under weak moisture environments and a persistent torrential rainfall event with abundant water vapor in the summer are selected as test examples for comparative analysis of the relationships between water vapor divergence and precipitation characteristics with the adoptions of both traditional synoptic diagnosis and two decomposition methods. It is found that divergent areas of the total water vapor flux divergence at the middle and high levels are blocked by false convergence at the low levels as the precipitation weakens in both cases, which leads to the failure of traditional synoptic diagnoses. Meanwhile, the two decomposition methods can provide superior indicators for extreme precipitation, especially before rainfall decreases or terminates. The synoptic approach performs better than the Barnes filter method as the latter sharply decreases in accuracy as the complexity of the flow fields and moisture conditions increase. Remedies for relieving this problem are proposed before being used for further applications. |
| first_indexed | 2024-04-14T02:03:12Z |
| format | Article |
| id | doaj.art-0fdcfe9d8b36475ab44787bde21c4a7a |
| institution | Directory Open Access Journal |
| issn | 2296-6463 |
| language | English |
| last_indexed | 2024-04-14T02:03:12Z |
| publishDate | 2022-08-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Earth Science |
| spelling | doaj.art-0fdcfe9d8b36475ab44787bde21c4a7a2022-12-22T02:18:45ZengFrontiers Media S.A.Frontiers in Earth Science2296-64632022-08-011010.3389/feart.2022.847317847317Comparative analysis of two flow decomposition approaches and their applications in diagnosing water vapor in extreme precipitation events over Xinjiang province, ChinaJie Cao0Shuping Ma1Shuping Ma2Lingkun Ran3Key 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, ChinaSchool of Geography and Planning, Ningxia University, Yinchuan, ChinaInstitute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, ChinaInstitute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, ChinaWater vapor flux divergence under the terrain-following coordinate system is decomposed into slow and fast manifolds with the adoption of the Barnes filter method and the synoptic approach based on the Helmholtz theorem in this study. The performances and applications of both methods are evaluated in precipitating events over the Xinjiang province in China when traditional analysis fails to capture the evolutions of extreme precipitations caused by multi-scale systems and complicated terrains. A blizzard with a short duration under weak moisture environments and a persistent torrential rainfall event with abundant water vapor in the summer are selected as test examples for comparative analysis of the relationships between water vapor divergence and precipitation characteristics with the adoptions of both traditional synoptic diagnosis and two decomposition methods. It is found that divergent areas of the total water vapor flux divergence at the middle and high levels are blocked by false convergence at the low levels as the precipitation weakens in both cases, which leads to the failure of traditional synoptic diagnoses. Meanwhile, the two decomposition methods can provide superior indicators for extreme precipitation, especially before rainfall decreases or terminates. The synoptic approach performs better than the Barnes filter method as the latter sharply decreases in accuracy as the complexity of the flow fields and moisture conditions increase. Remedies for relieving this problem are proposed before being used for further applications.https://www.frontiersin.org/articles/10.3389/feart.2022.847317/fullextreme precipitationflow decompositionHelmholtz theoremBarnes filtermoisture flux divergence |
| spellingShingle | Jie Cao Shuping Ma Shuping Ma Lingkun Ran Comparative analysis of two flow decomposition approaches and their applications in diagnosing water vapor in extreme precipitation events over Xinjiang province, China Frontiers in Earth Science extreme precipitation flow decomposition Helmholtz theorem Barnes filter moisture flux divergence |
| title | Comparative analysis of two flow decomposition approaches and their applications in diagnosing water vapor in extreme precipitation events over Xinjiang province, China |
| title_full | Comparative analysis of two flow decomposition approaches and their applications in diagnosing water vapor in extreme precipitation events over Xinjiang province, China |
| title_fullStr | Comparative analysis of two flow decomposition approaches and their applications in diagnosing water vapor in extreme precipitation events over Xinjiang province, China |
| title_full_unstemmed | Comparative analysis of two flow decomposition approaches and their applications in diagnosing water vapor in extreme precipitation events over Xinjiang province, China |
| title_short | Comparative analysis of two flow decomposition approaches and their applications in diagnosing water vapor in extreme precipitation events over Xinjiang province, China |
| title_sort | comparative analysis of two flow decomposition approaches and their applications in diagnosing water vapor in extreme precipitation events over xinjiang province china |
| topic | extreme precipitation flow decomposition Helmholtz theorem Barnes filter moisture flux divergence |
| url | https://www.frontiersin.org/articles/10.3389/feart.2022.847317/full |
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