Three-Dimensional Structural Anomalies of the Western Pacific Subtropical High Ridge and Its Relationship with Precipitation in China during August–September 2021
In August-September 2021, the western Pacific subtropical high (WPSH) showed significant anomalies, with some areas between the Yangtze and Yellow River basins in China suffering from heavy rainfall and flooding, while extreme heat occurred in Southern China. Using the 6 h reanalysis data of NCEP/NC...
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MDPI AG
2022-07-01
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| Series: | Atmosphere |
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| Online Access: | https://www.mdpi.com/2073-4433/13/7/1089 |
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| author | Fei Zhang Xianyu Yang Qingfei Sun Suxiang Yao Qu Guo |
| author_facet | Fei Zhang Xianyu Yang Qingfei Sun Suxiang Yao Qu Guo |
| author_sort | Fei Zhang |
| collection | DOAJ |
| description | In August-September 2021, the western Pacific subtropical high (WPSH) showed significant anomalies, with some areas between the Yangtze and Yellow River basins in China suffering from heavy rainfall and flooding, while extreme heat occurred in Southern China. Using the 6 h reanalysis data of NCEP/NCAR and the daily precipitation observation data, this paper studied the abnormal characteristics and the thermal mechanism of the three-dimensional ridge of the WPSH during the seasonal transition from late summer to early autumn in August-September 2021, and explored its connection with the precipitation in the areas between the Yangtze and Yellow River basins in China during the same period. The results showed that, in August-September 2021, the three-dimensional ridge of the WPSH appeared to be southward at the lower troposphere and tilted northward with height. According to the diagnosis of the atmospheric heat source, it was found that the center of atmospheric cold source in the low latitudes at 850 hPa enhanced the surface high pressure, corresponding to the WPSH ridge shifting southward at the lower troposphere, which led to more water vapor convergence and more precipitation between the Yangtze and Yellow River basins. The latent heat of condensation released by the increased precipitation between the Yangtze and Yellow River basins in China heated the middle and upper troposphere, increasing the intensity of the high pressure in the upper troposphere, corresponding to the WPSH ridge northward at the upper troposphere. This anomalous tilt of the WPSH ridge in August-September 2021 and the intense precipitation processes between the Yangtze and Yellow River basins in China during the same period established a reciprocal feedback mechanism through diabatic heating. Further studies also showed that the anomalous tilt of the WPSH ridge is one of the important modes of its three-dimensional structural anomalies, and that, in years when the ridge tilts from south to north with height anomalously in August-September, the areas between the Yangtze and Yellow River basins are characterized by high precipitation. |
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| language | English |
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| series | Atmosphere |
| spelling | doaj.art-b3aa73a451fc4b8a8ae8acb51aaefc062023-12-03T14:38:47ZengMDPI AGAtmosphere2073-44332022-07-01137108910.3390/atmos13071089Three-Dimensional Structural Anomalies of the Western Pacific Subtropical High Ridge and Its Relationship with Precipitation in China during August–September 2021Fei Zhang0Xianyu Yang1Qingfei Sun2Suxiang Yao3Qu Guo4Key Laboratory of Meteorological Disaster, Ministry of Education (KLME), Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters (CIC-FEMD), Joint International Research Laboratory of Climate and Environment Change (ILCEC), Nanjing University of Information Science and Technology, Nanjing 210044, ChinaPlateau Atmosphere and Environment Key Laboratory of Sichuan Province, School of Atmospheric Sciences, Chengdu University of Information Technology, Chengdu 610225, ChinaYizheng Meteorological Bureau, Yizheng 211400, ChinaKey Laboratory of Meteorological Disaster, Ministry of Education (KLME), Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters (CIC-FEMD), Joint International Research Laboratory of Climate and Environment Change (ILCEC), Nanjing University of Information Science and Technology, Nanjing 210044, ChinaChongqing Climate Center, Chongqing 401147, ChinaIn August-September 2021, the western Pacific subtropical high (WPSH) showed significant anomalies, with some areas between the Yangtze and Yellow River basins in China suffering from heavy rainfall and flooding, while extreme heat occurred in Southern China. Using the 6 h reanalysis data of NCEP/NCAR and the daily precipitation observation data, this paper studied the abnormal characteristics and the thermal mechanism of the three-dimensional ridge of the WPSH during the seasonal transition from late summer to early autumn in August-September 2021, and explored its connection with the precipitation in the areas between the Yangtze and Yellow River basins in China during the same period. The results showed that, in August-September 2021, the three-dimensional ridge of the WPSH appeared to be southward at the lower troposphere and tilted northward with height. According to the diagnosis of the atmospheric heat source, it was found that the center of atmospheric cold source in the low latitudes at 850 hPa enhanced the surface high pressure, corresponding to the WPSH ridge shifting southward at the lower troposphere, which led to more water vapor convergence and more precipitation between the Yangtze and Yellow River basins. The latent heat of condensation released by the increased precipitation between the Yangtze and Yellow River basins in China heated the middle and upper troposphere, increasing the intensity of the high pressure in the upper troposphere, corresponding to the WPSH ridge northward at the upper troposphere. This anomalous tilt of the WPSH ridge in August-September 2021 and the intense precipitation processes between the Yangtze and Yellow River basins in China during the same period established a reciprocal feedback mechanism through diabatic heating. Further studies also showed that the anomalous tilt of the WPSH ridge is one of the important modes of its three-dimensional structural anomalies, and that, in years when the ridge tilts from south to north with height anomalously in August-September, the areas between the Yangtze and Yellow River basins are characterized by high precipitation.https://www.mdpi.com/2073-4433/13/7/1089WPSHridgethe diabatic heatingprecipitation |
| spellingShingle | Fei Zhang Xianyu Yang Qingfei Sun Suxiang Yao Qu Guo Three-Dimensional Structural Anomalies of the Western Pacific Subtropical High Ridge and Its Relationship with Precipitation in China during August–September 2021 Atmosphere WPSH ridge the diabatic heating precipitation |
| title | Three-Dimensional Structural Anomalies of the Western Pacific Subtropical High Ridge and Its Relationship with Precipitation in China during August–September 2021 |
| title_full | Three-Dimensional Structural Anomalies of the Western Pacific Subtropical High Ridge and Its Relationship with Precipitation in China during August–September 2021 |
| title_fullStr | Three-Dimensional Structural Anomalies of the Western Pacific Subtropical High Ridge and Its Relationship with Precipitation in China during August–September 2021 |
| title_full_unstemmed | Three-Dimensional Structural Anomalies of the Western Pacific Subtropical High Ridge and Its Relationship with Precipitation in China during August–September 2021 |
| title_short | Three-Dimensional Structural Anomalies of the Western Pacific Subtropical High Ridge and Its Relationship with Precipitation in China during August–September 2021 |
| title_sort | three dimensional structural anomalies of the western pacific subtropical high ridge and its relationship with precipitation in china during august september 2021 |
| topic | WPSH ridge the diabatic heating precipitation |
| url | https://www.mdpi.com/2073-4433/13/7/1089 |
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