与天气系统发生和发展有关的非均匀饱和湿位涡理论分析  

THEORETICAL ANALYSIS OF NON-UNIFORM SATURATED MOIST POTENTIAL VORTICITY(NUSMPV) ASSOCIATED WITH THE OCCURRENCE AND DEVELOPMENT OF WEATHER SYSTEMS

作　　者：王兴荣[1] 魏鸣[2] 

机构地区：[1]安徽省气象科学研究所,安徽合肥230061 [2]南京信息工程大学中美合作遥感实验室江苏省气象灾害重点实验室,江苏南京210044

出　　处：《热带气象学报》2007年第5期459-466,共8页Journal of Tropical Meteorology

摘　　要：在动力气象理论方面,无论大尺度、中尺度还是小尺度大气运动,对于同一尺度之内大气运动演变机制,有着相当完美的讨论。然而,对于不同尺度天气系统之间转换演变机制讨论,即使因为它与天气系统的出现和发展密切相关而显得非常重要,却很少涉及。为了讨论这个重要的转换演变机制,在导出无粘滞非均匀饱和湿位涡(NUSMPV)方程的基础上,首先,通过对这方程进行数理分析证明:在非均匀饱和湿绝热大气运动中,干区和饱和区之间的不饱和区的NUSMPV是不守恒的,并进一步证明:只在次饱和区(0.78<q/qs<1),NUSMPV不守恒才是明显的,而在其它不饱和区,NUSMPV是接近守恒的。接着,根据守恒的相对性原理,通过NUSMPV无因次形式的讨论,把大气运动分成三类,即NUSMPV守恒,准守恒和不守恒运动。然后用数理分析方法讨论了各类运动的出现条件,时空之间关系,物理机制和一些特征。最后分析了不同尺度之间天气系统的转换机制,指出:当与狭义NUSMPV(P0)有关的涡管项(A)和非绝热加热项(B)之间的动力不平衡(A+B)/P0减少,以至NUSMPV守恒条件满足时,大气运动将主要通过非常快的频散适应过程继续失去不平衡能量,从较小尺度向较大尺度转换;而当(A+B)/P0增加,以至NUSMPV不守恒条件满足时,大气运动将主要通过非常快的外源激发过程,而从较大尺度向较小尺度转换。无论上述两种转换过程是那一种,一旦产生都将持续进行,直至大气运动重新回到NUSMPV准守恒运动状态。At present, in the theory of dynamical meteorology, whether it is a large-scale, meso-scale or small-scale atmospheric movement, there are many quite prefect discussions on the evolution mechanism of atmospheric motion within a single scale. However, there is little discussion on the transformation between weather systems of different scale, even though it is obviously important because it is related to the occurrence and development of weather systems. To discuss the above important transformation mechanism problem, the equation of the frictionless and non- uniform saturated moist potential vorticity （NUSMPV） is derived in this article. First, by mathematical and physical analysis of the equation, it is shown that, in moist adiabatic atmospheric motion, the NUSMPV of the motion is not conserved in the unsaturated regions between the dry area and saturated moist area. It is further shown that in the sub-saturated regions （0.78〈q/qs〈1） the NUSMPV is not conserved; whereas, in the other unsaturated regions, the NUSMPV may be nearly conserved. Second, according to the relativity principle of conservation, by discussing the non-dimensional form of the NUSMPV equation, the atmospheric motion is classified into three types： motions with conserved, quasi-conserved, and non-conserved NUSMPV. By mathematical and physical analysis, the occurrence condition, the relation between space and time, physical mechanism, and some characteristics are studied for each type of motion. Finally, the transformation mechanism between the synoptic systems of different scale is analyzed. It is pointed out as follows. When the dynamic non-equilibrium degree, which is related to the narrow sense NUSMPV （P0）, between the solenoidal term （A） and diabetic heating （B）, i.e. （A＋B）/P0, decreases so that the condition of NUSMPV conservation is satisfied, the atmospheric motion in NUSMPV conservation state transforms from smaller scale to larger scale mainly by the very fast adaptation process in which the non-equilib

关 键 词：非均匀饱和湿位涡 不同尺度之间天气系统 转换机制 

分 类 号：P433[天文地球—大气科学及气象学]