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Quadrant-Averaged Structure and Evolution Mechanisms of a Northeast Cold Vortex during Its Mature Stage |
LI Wei1,2, SHEN Xin-Yong1, FU Shen-Ming3, and LI Wan-Li4 |
1Key Laboratory of Meteorological Disaster of Ministry of Education, Nanjing University of Information Science and Technology, Nanjing 210044, China
2Hebei Meteorological Bureau, Shijiazhuang 050021, China
3International Center for Climate and Environment Sciences, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
4China Meteorological Administration Training Center, Beijing 100081, China |
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Abstract A Northeast China cold vortex (NCCV) that maintained from 0200 UTC 3 July to 0500 UTC 3 July 2013 and caused several heavy rainfall events was analyzed in detail to reveal its quadrant-averaged structure and main maintaining mechanisms during its mature stage. Results indicated the vortex’s intensity, divergence, ascending motions, precipitable water (PW), and thermal structures were all characterized by significant unevenness, and their main pattern changed gradually during the mature stage. Mechanisms accounting for the maintenance of the NCCV were also characterized by remarkable unevenness. Within different quadrants, dominant factors for the vortex’s evolution may have differed from each other significantly. The NCCV-averaged vorticity budget revealed that the vertical advection of vorticity, which is closely related to convective activities, was the most favorable factor for maintaining the NCCV, whereas the tilting effect, which is closely related to the vertical shear of the horizontal wind (horizontal vorticity), was the most detrimental factor.
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Received: 27 May 2014
Revised: 14 October 2014
Accepted: 15 November 2014
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Corresponding Author:
FU Shen-Ming
E-mail: fusm@mail.iap.ac.cn
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