摘要
利用1958—2011年NCEP/NCAR逐日再分析资料,根据Lorenz能量循环理论框架,分析了北半球大气能量循环的年变化特征,在此基础上给出了更具普适性的多年平均的大气能量循环框图。结果表明:北半球大气能量循环的年变化特征十分明显。大气能量及能量转换率均表现为冬季高、夏季低、春秋季过渡的演变特征;纬向平均有效位能、纬向平均动能和涡动动能中有少许能量在冬季时由南半球向北半球进行越赤道输送,夏季时则由北半球向南半球输送,而涡动有效位能的输送方向则与此相反;纬向平均有效位能的制造在秋季最大,涡动有效位能的制造在夏季最大;动能的耗散冬季最强,夏季最弱。就年平均而言,相较于能量转化过程,能量越赤道交换过程非常微弱。在经向上,纬向平均有效位能主要分布于高纬地区,纬向平均动能主要分布于中低纬地区,而涡动能量主要贮存在中纬和高纬地区;此外,能量转化过程一般在中纬度地区较活跃。
According to the framework of energy cycle proposed by Lorenz in 1967 ,the atmospheric energy cycle is estimated on a monthly basis in the Northern Hemisphere using the NCEP/NCAR reanaly- sis daily data for the period of 1958-2011.The annual variations of energy reservoirs ,conversions ,exchanges across the equator, generations and dissipations have been investigated in the present paper.The results show that the energy cycle of the Northern Hemispheric atmosphere varies on annual time-scale evidently.Reservoirs and conversion rates change in the same phase, with values larger in winter, smaller in summer.In winter, the zonal mean energies and eddy kinetic energy are transported northward from the Southern Hemisphere into the Northern Hemisphere. However, in boreal summer, they are transported southward from the Northern Hemisphere into the Southern Hemisphere, whereas the exchange of eddy available potential energy at the equatorial boundary is in contrast.A maximum in generation of the zonal mean available potential energy takes place in the fall, and the generation of eddy available potential energy has a maximum in the summer.The dissipations of both zonal mean and eddy kinetic energy are stronger in winter but weaker in summer.In the annual mean case, the cross-equatorial fluxes are smaller than the energy conversion processes. In the meridional direction, the zonal mean available potential energy mainly appears in high-latitudes, the zonal mean kinetic energy mainly in mid- and low-latitudes ,and the eddy energies mainly in mid-and high-latitudes.Further more ,the conversion processes of atmospheric energies are more active in the middle latitude regions.
出处
《大气科学学报》
CSCD
北大核心
2015年第4期531-539,共9页
Transactions of Atmospheric Sciences
基金
国家自然科学基金资助项目(41105056
41175062)
江苏省研究生科研创新计划项目(CXZZ12-0485)
江苏省青蓝工程创新团队及高校优势学科工程(PAPD)
关键词
能量循环
有效位能
动能
年变化
energy cycle
available potential energy
kinetic energy
annual variation
