[1]LONG Xiyu,ZHANG Xinzhu,ZHANG Xinping,et al.Analysis on the Characteristices of Circulation Evolution of Extreme Rainfall Events During the Rainy Season in Donting Lake Basin[J].Research of Soil and Water Conservation,2020,27(02):158-164,177.
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Research of Soil and Water Conservation[ISSN 1005-3409/CN 61-1272/P] Volume:
27
Number of periods:
2020 02
Page number:
158-164,177
Column:
Public date:
2020-03-30
- Title:
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Analysis on the Characteristices of Circulation Evolution of Extreme Rainfall Events During the Rainy Season in Donting Lake Basin
- Author(s):
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LONG Xiyu1, ZHANG Xinzhu1, ZHANG Xinping1, LI Qiaoyuan2
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(1.College of Resources and Environmental Sciences, Hunan Normal University, Changsha 410081, China; 2.Hunan Provincial Meteorological Station, Changsha 410118, China)
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- Keywords:
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extreme rainfall; som-k clustering; circulation evolution
- CLC:
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P426.6
- DOI:
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- Abstract:
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Based on the daily precipitation data of 56 years(1961—2016)in 85 meteorological stations and daily reanalysis dataset from NCEP, a detailed analysis is performed to understand the circulation evolution characteristices of extreme rainfall events(ERT)during the rainy reason(May to September)in Dongting Lake Basin. Som-k(Self Organizing Map and kmeans)is used to cluster the ERT. Based on the foregoing work, the evolution characteristices of different regions of ERT are explored. The results show that there are many reasons for the extreme rainfall, such as the development of low tropospheric cyclonic vorticity, the enhancement of trough at 500 hPa and the enhancement of convergence zone in the southeast side of Dongting Lake Basin, and the central area of upward flow is enhanced and moves northward. Although the anomalous moisture transport channels of ERT in various regions are not consistent, the source of anomalous moisture is basically the same. The excessive anomalous moisture transported from the Bay of Bengal, the South China Sea and the Western Pacific plays an important role in producing environmental conditions favorable for ERT. The seasonal variation of the Western Pacific subtropical high pressure and the difference of synoptic condition cause the spatial variability of the main extreme rainfall rain-band together in Dongting Lake Basin: the ERT of northern region cover about 27°—30°N, which concentrate in June and July, ERT of the central region cover about 26°—27°N, which concentrate in May and June; and ERT of the south region cover about 25°—26°N, which concentrate in May and June. The extreme precipitation rain-band and the location of the anomalous moisture convergence center zone of each category region are coincident.