Study on cut-off low-pressure systems with floods over Northeast Asia

被引:80
作者
Zhao, Sixiong [1 ]
Sun, Jianhua [1 ]
机构
[1] Chinese Acad Sci, Inst Atmospher Phys, Beijing 100029, Peoples R China
关键词
D O I
10.1007/s00703-006-0226-3
中图分类号
P4 [大气科学(气象学)];
学科分类号
0706 ; 070601 ;
摘要
The cut-off lows (COLs) during the period from June to August 1998 leading to the record flood in Northeast Asia, especially in Northeast China, has been investigated in this paper. The results are as follows: the blocking highs benefited significantly the formation and maintenance of COLs over Northeast China; an obvious frontogenesis zone existed in Northeast China and it implies that baroclinity played an important role in the initiation of COLs, especially in middle and upper troposphere; the maxima of the potential vorticity anomaly were located in the upper troposphere, then extended downwards to the middle and the lower troposphere. The pronounced interaction between systems in upper-middle and low troposphere can be revealed; the moisture supply was from South China, and even from East China Sea and South China Sea. The strong southerly current transported very rich moisture to Northeast China. The maximum of the convergence of moisture flux was below 850 hPa. Obvious interaction between the middle and lower latitude systems was found in the study. Also, the summer monsoon showed significant impacts on the sustained heavy rainfalls related with the COLs over Northeast China; the upward motion could be caused by the lifting of the large scale dynamic forcing and there was no obvious releasing of latent heating in the upper-middle troposphere. The cold dome in the COLs was quite different both from the warm core in tropical cyclone and from the weaker warm core in Meiyu (Baiu) front low. The calculation of vorticity budget shows that both the horizontal advection term and horizontal divergence term contributed importantly to the maintenance and the strengthening of positive relative vorticity. Finally, the complex dynamical characteristics regarding the COLs are discussed and further investigation is proposed.
引用
收藏
页码:159 / 180
页数:22
相关论文
共 41 条
[1]   Numerical simulation of a heavy rainfall event in China during July 1998 [J].
Bei, NF ;
Zhao, SX ;
Gao, ST .
METEOROLOGY AND ATMOSPHERIC PHYSICS, 2002, 80 (1-4) :153-164
[2]  
DAGGUPATY SM, 1977, J ATMOS SCI, V34, P773, DOI 10.1175/1520-0469(1977)034<0773:OTVBAV>2.0.CO
[3]  
2
[4]  
Doty R., 1995, GRID ANAL DISPLAY SY, V3
[5]  
HILL FF, 1987, METEOROL MAG, V116, P297
[6]  
HOSKINS BJ, 1980, Q J ROY METEOR SOC, V106, P707, DOI 10.1002/qj.49710645004
[7]   ON THE USE AND SIGNIFICANCE OF ISENTROPIC POTENTIAL VORTICITY MAPS [J].
HOSKINS, BJ ;
MCINTYRE, ME ;
ROBERTSON, AW .
QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, 1985, 111 (470) :877-946
[8]  
HSIEH YP, 1949, J METEOROL, V6, P401, DOI 10.1175/1520-0469(1949)006<0401:AIOASC>2.0.CO
[9]  
2
[10]  
Kalnay E, 1996, B AM METEOROL SOC, V77, P437, DOI 10.1175/1520-0477(1996)077<0437:TNYRP>2.0.CO