DOI: 10.1007/s00382-015-2885-6
Scopus记录号: 2-s2.0-84946139502
论文题名: Mechanisms for concurrent low-latitude circulation anomalies responsible for persistent extreme precipitation in the Yangtze River Valley
作者: Chen Y. ; Zhai P.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2016
卷: 47, 期: 2017-03-04 起始页码: 989
结束页码: 1006
语种: 英语
英文关键词: Diabatic heating
; Mechanisms
; Persistent extreme precipitation
; Precursors
; Vorticity budget
英文摘要: Concurrent position shifts of the mid-level western Pacific subtropical high (WPSH) and the upper-level South Asia high (SAH) are regarded as significant precursors for persistent extreme precipitation events (PEPEs) in the Yangtze River Valley (YRV). By performing composite analyses, accountable vorticity genesis and dissipation are diagnosed based on a potential vorticity–diabatic heating theory. The results indicate that about 1 week preceding precipitation onset, a wave-like pattern of anomalous diabatic heating (Q) initiates its northwestward propagation from equatorial central Pacific. Subsequently, this wave-like pattern induces substantial changes in both horizontal and vertical structure of local Q along the propagating route. Forced negative vorticities in key areas result in the zonal approach between the SAH and the WPSH. During PEPEs, two thermal-induced vertical circulation cells take shape, with common strong ascent centered in the YRV. These anomalous cells are capable of self-maintaining for a few days via positive feedback processes. The WPSH and the SAH are therefore anchored in respective favorable positions for PEPEs. Simultaneously, descending motion of these two cells increases local solar radiation and decreases upward latent heat flux from surface, facilitating warmer underlying surface and swift accumulation of lower-level moisture. Correspondingly, enhanced heating to the north and rapid developing cyclone over warmer sea surface to the south combine to terminate above positive feedback processes. Finally, both the WPSH and the SAH retreat to their normal positions, accompanied by a quick decay of PEPEs. © 2015, The Author(s). Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/53580
Appears in Collections: 过去全球变化的重建
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作者单位: Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science and Technology, Nanjing, China; State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, CMA, No. 46, South Ave. Zhong-guan-cun, Haidian, Beijing, China
Recommended Citation:
Chen Y.,Zhai P.. Mechanisms for concurrent low-latitude circulation anomalies responsible for persistent extreme precipitation in the Yangtze River Valley[J]. Climate Dynamics,2016-01-01,47(2017-03-04)