1998年长江流域夏季降水异常的一个物理机制

陶云; 赵荻; 杨明

1998年长江流域夏季降水异常的一个物理机制

陶云¹,
赵荻²,
杨明³

1.
云南省气候中心, 云南, 昆明, 650034;云南大学大气科学系, 云南, 昆明, 650091
2.
云南大学大气科学系, 云南, 昆明, 650091
3.
云南省气象台, 云南, 昆明, 650034

基金项目: 国家青年科学自然基金项目(40305005);国家自然科学研究基金重点项目(40233033);国家自然科学研究基金(40475040)

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出版历程
- 收稿日期: 2005-09-12
- 修回日期: 2006-01-06

A POSSIBLE MECHANISM FOR THE ABNORMAL SUMMER RAINFALL OVER YANGTZE RIVER VALLEY IN 1998

1.
Climate Center of Yunnan Province, Kunming 650034, China;Atmospheric Science Department of Yunnan University, Kunming 650091, China
2.
Atmospheric Science Department of Yunnan University, Kunming 650091, China
3.
Meteorological Observatory of Yunnan, Kunming 650034, China

摘要

摘要: 根据1998年北半球夏季6、7、8月逐月500hPa高度场实测资料,利用具有双重筛选功能的二维空间谱分析方法,分别获得了能大致反映1998年北半球6、7、8月500hPa高度场分布特征的3组空间波集,每组包含15个空间波。分别利用这3组空间谱函数,从Galerkin途径出发,获得了1998年长江流域夏季降水异常的一个物理机制:在前期典型ElNiño型海温异常,以及5月后ElNiño型海温异常减弱,Laniña型海温异常分布建立的这些外部异常热力强迫作用下,导致大气环流出现不同的非线性内部动力过程,6月大气环流演变中波波相互作用和波流相互作用较弱,7、8月的大气环流演变中尽管波波相互作用明显,但波流相互作用仍然很弱。波流相互作用的持续偏弱,导致了1998年夏季西太平洋副热带高压位置持续偏南,夏季强降雨带持续稳定于长江流域。
- 长江流域夏季降水 /
- 空间谱分析 /
- Galerkin方法 /
- 热力强迫 /
- 副热带高压
Abstract: Based on observed height data,three-set spatial waves mainly describing the characteristics on the North Hemispheric 500 hPa height field of June,July and August in 1998 were obtained with 2-dimension spatial spectrum analysis method.There were 15 waves in each set.Based on the three-set spatial spectrum functions,a possible mechanism for the abnormal summer rainfall over Yangtze River valley in 1998 was obtained with the Galerkin method.The mechanism indicated that forced by a special sea surface temperature anomaly distribution which belonged to the El Niño pattern before May,then to the decreasing El Niño pattern,and finally to the La Niña pattern,there were different inner nonlinear dynamic processes in the atmospheric circulation.In June,there were weaker wave-wave and wave-mean flow interactions.Although there was stronger wave-wave interaction,there was weaker wave-mean flow interaction.The persistently weaker wave-mean flow interaction made the western Pacific subtropical to be positioned more southward than normal during the summer of 1998,and then cause the heavy rainfall belt to maintain over the Yangtze River valley.
- summer rainfall over Yangtze valley /
- spatial spectrum analysis /
- Galerkin method /
- thermal forcing /
- subtropical high

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参考文献(20)

[1]	GERALD D B,MIiCHAEL S H,CHESTER F R,et al.Climate Assessment for 1998[J].Bulletin of the American Meteorological Society,1999,80(5):1040-1088.
[2]	陶诗言,张庆云,张顺利.1998年长江流域灾害的气候背景和大尺度环流条件[J].气候与环境,1998,3(4):289-299.
[3]	黄荣辉,徐予红,王鹏飞,等.1998年夏季长江流域特大洪涝特征及其成因探讨[J].气候与环境,1998,3(4):300-313.
[4]	李维京.1998年大气环流异常及其对中国气候异常的影响[J].气象,1999,25(4):20-25.
[5]	王会军.关于我国几个大水年大气环流特征的几点思考[J].应用气象学报,2002,11(增刊):79-86.
[6]	Shen Xueshun,Masahide Kimoto,Akimasa Sumi,et al.Simulation of the 1998 East Asian summer monsoon by the CCSR/NIES AGCM[J].Journal of the Meteorological Society of Japan,2001,79 (3):741-757.
[7]	Nakazawa Tetsuo.Suppressed tropical cyclone formation over the Western North Pacific in 1998[J].Journal of the Meteorological Society of Japan,2001,79 (1):173-183.
[8]	苗秋菊,徐祥德,张雪金.长江中下游旱涝的环流型与赤道东太平洋海温遥相关波列特征[J].气象学报,2002,60(6):687-696.
[9]	王亚非,高桥清利.长江中下游降水以及东亚夏季风环流的年代际变化[J].热带气象学报,2005,21(4):351-358.
[10]	琚建华,赵尔旭.东亚夏季风区的低频振荡对长江中下游旱涝的影响[J].热带气象学报,2005,21(2):163-171.
[11]	苗娟,林振山.我国九大气候区降水特性及其物理成因的研究Ⅱ:我国各区降水与环流因子的关系[J].热带气象学报,2004,20(1):64-72.
[12]	吕俊梅,任菊章,琚建华.东亚夏季风的年代际变化对中国降水的影响[J].热带气象学报,2004,20(1):73-80.
[13]	中国气象局国家气候中心.1998中国大洪水与气候异常[M].北京:气象出版社,1998:1-24.
[14]	Kalnay E M,Kanamitsu R K,Collins W,et al.The NCEP/NCAR 40-year reanalysis project[J].Bull Amer Meteor Soc,1996,77(3):437-471.
[15]	黄嘉佑,李黄.气象中的谱分析[M].北京:气象出版社,1984:254-262.
[16]	曹杰,尤亚磊.低阶谱模式的一种新方案及其应用[J].应用数学和力学,2006,27(4):424-430.
[17]	朱抱真,金飞飞,刘征宇.大气和海洋的非线性动力学概论[M].北京:海洋出版社,1991:41-42.
[18]	曹杰,黄荣辉,谢应齐,等.西太平洋副热带高压演变物理机制的研究[J].中国科学D,2002,32(8):659-666.
[19]	缪锦海,丁敏芳.热力强迫下大气平衡态的突变与季节变化、副高北跳[J].中国科学B,1985,(1):87-96.
[20]	Zhang Renhe,Zhao Gang.Meridional wind stress anomalies over tropical pacific and the onset of El Nino Part Ⅱ:Dynamical analysis[J].AdvAtmos Sci,2001,18(6):1053-1065.