西风角动量输送的气候特征及其与急流关系研究  

Climatic Characteristics of Relative Atmospheric Angular Momentum Transport and Its Relationship with Jet Streams

作　　者：杨玮[1,2] 王盘兴[1] 何金海[1] 李丽平[1] 成丽萍[1] 

机构地区：[1]南京信息工程大学气象灾害教育部重点实验室,南京210044 [2]安徽省气候中心,合肥230031

出　　处：《大气科学》2014年第2期363-372,共10页Chinese Journal of Atmospheric Sciences

基　　金：国家重点基础研究发展(973)计划2013CB430202;国家自然科学基金青年科学基金项目41205063;江苏省普通高校研究生科研创新计划CXZZ11_0608;江苏高校优势学科建设工程资助项目(PAPD)

摘　　要：摘要利用1958-1997年NCEP／NCAR一日四次的风场再分析资料，系统地分析了季节平均西风角动量（即U角动量）经向、垂直输送通量及其三个分量（平均经圈环流、定常波、瞬变涡输送通量）的气候特征，特别是讨论了12-2月、6-8月它们与东、西风带、副热带西风急流、极夜急流之间的联系。结果表明：（1）包含纬度因子的角动量通量与动量通量在高纬地区存在显著差别，高纬对流层上部的强动量输送中心在角动量通量中不明显。而U角动量强经向输送主要在中低纬对流层顶附近和冬半球高纬平流层项附近，副热带西风急流和极夜西风急流均位于“角动量强向极输送中心及其高纬一侧的辐合区中。（2）发现三个输送分量对急流维持的作用随纬度、季节不同。北半球冬季（夏季）的副热带西风急流主要由平均经圈环流（强度相当的定常波和瞬变涡）强经向输送及辐合维持；南半球西风急流全年均由平均经圈环流和瞬变涡旋输送及辐合维持；冬半球中平流层极夜急流主要由定常波、瞬变涡旋输送及其辐合共同维持。（3）热带东风区是牵连角动量（即Q角动量）的高值区，它主要由平均经圈环流向对流层上部输送；冬半球副热带及中纬西风区存在“角动量垂直输送的切变区，它主要由平均经圈环流和瞬变涡旋完成；热带对流层顶附近有”角动量的定常波弱向下输送。Based on the NCEP/NCAR wind reanalysis data, the climatic seasonal mean relative atmospheric angular momentum transport flux and its three components （mean meridional circulation, stationary eddies, and transient eddies） are computed to investigate their relationships with easterlies, westerlies, the subtropical westerly jet, and the polar night jet in both winter and summer. The results show that： （1） The flux of angular momentum, including latitude factors and the flux of momentum, differs remarkably in high latitudes, where a strong momentum transport center is found in the upper troposphere. The strong meridional transport of u angular momentum mainly occurs in low latitudes around the tropopause and high latitudes near the stratosphere of both northern and southern hemispheres in winter. Both the subtropical westerly jet and polar night jet demonstrate poleward transport of their centers with convergence zones in thehigh latitudes. （2） The roles of the three aforementioned components on jet maintenance change with latitudes and seasons In the northern hemisphere winter, the subtropical westerly jet is mainly maintained by strong meridional transport and convergence of mean meridional circulation, owing to equivalent stationary eddies and transient eddies. In the northern hemisphere summer, however, the role of the mean meridional circulation diminishes and the stationary and transient eddies are the most important factors at work. In contrast, fluxes in the southern hemisphere are more easily identified, as they are maintained all year by meridional transports and the convergence of the mean meridional circulation and transient eddies. The polar night jet in winter hemisphere, occurring in the middle stratosphere, is mainly maintained by meridional transports and the convergence of stationary and transient eddies. （3） In the tropical easterlies, g2 angular momentum appears as high values and is transported to the upper troposphere mainly by the mean meridional circulation. In winter hemisph

关 键 词：u角动量通量 经向输送 垂直输送 副热带西风急流 极夜急流 

分 类 号：P434.5[天文地球—大气科学及气象学]