【作者】 邓淑梅；

【导师】 陈月娟；

【作者基本信息】 中国科学技术大学 ， 空间物理， 2007， 博士

【摘要】 平流层爆发性增温(SSW)是平流层大气的重要特征之一，一直以来围绕着平流层爆发性增温的环流变化以及它与行星波之间的关系国内外开展了一系列研究，并且逐渐成为平流层大气研究的一个热点和前沿问题。为了进一步搞清楚平流层爆发性增温的动力学特征、它对平流层微量成分含量和分布的影响以及它对对流层的影响，本文在资料统计和分析平流层爆发性增温的时空分布特征的基础上，计算了SSW期间的E-P通量，讨论了SSW期间行星波的活动和变化；计算了剩余环流，讨论了SSW期间剩余环流的瞬变特征及其对臭氧的输送；用HALOE资料分析了爆发性增温期间其它微量气体分布的变化；通过NAM分析了爆发性增温对气候尤其是东亚气候的可能影响。得到以下的结果和新的认识：第一，通过NCEP再分析资料的统计分析，表明SSW具有以下的统计特征：平流层爆发性增温发生的频数具有月际变化的特征，多发生在3月份；SSW发生时暖中心位置随高度变化，在每个高度层表现出很强的地域性，SSW通常发生在较高层，然后由上向下延伸和传播，在增温下传的过程中增暖中心的位置也在发生着变化，在较高层暖中心首先出现在东半球，随着增温的下传暖中心逐渐经过180°子午面沿逆时针移向西半球；SSW发生时，不但高纬的温度场发生变化，中低纬的温度也发生变化：高纬增温，低纬降温；南半球2002年9月的一次强爆发性增温发生时，表现出的特征与北半球的SSW相似。第二，本文通过NECP资料对多年平流层爆发性增温期间位势高度场进行谐波分析，发现在平流层爆发性增温过程中行星波的活动与Labitzke所指出的不尽相同，尽管增温前行星波1波都异常发展增温期间明显减弱，但2波在增温过程中有其不同的特点。对于不同的行星波活动，极涡崩溃的形式也不同。据此将平流层爆发性增温过程中的行星波活动分为三类；(1)在增温前期，行星波2波很弱；在增温期间，行星波2波异常发展，伴随着极涡崩溃的形式是由偏心型向偶极型过渡；(2)在增温前期，行星波2波较强；在增温期间，行星波2波明显减弱，极涡的变化形式是远离极地，在极地外围活动，但不发生分裂；(3)在增温前期，行星波2波不太强；在增温期间，行星波2波有所发展，但始终强不过1波，极涡的变化是先偏离极地，然后发生不对称的变形。通过E-P通量来讨论这三种类型的行星波变化，指出无论是行星波2波的哪种活动类型，都有利于平流层爆发性增温的发生和发展。第三，本文利用ECMWF逐日再分析资料通过变形欧拉平均的热力学方程和连续计算了爆发性增温过程中的瞬变剩余环流并进行了合成分析，给出了增温过程中剩余环流变化的一般特征，同时还分析了高纬地区的瞬变剩余环流在爆发性增温过程中的变化。结果表明随着增温的开始10hPa～2 hPa气层瞬变剩余经向速度(?)逐渐由弱北风转为南风，随着增温加强其向北输送也随之增强，且其强度随着高度的增加而增大，增温减弱时它又慢慢变为弱的北风，并其强度较之增温开始时有所加强；而10hPa～2 hPa气层的垂直速度(?)随着增温的开始由弱的上升运动逐渐变为下沉运动，并且随着增温的加强其下沉运动加强，增温减弱时(?)也逐渐恢复为上升运动且强度也有所加强。本文还对考虑波加热项和不考虑波加热项得到的剩余环流进行对比，指出波加热项在极地附近的平流层上层还是有影响的，值得考虑。第四，利用ECMWF逐日再分析资料结合HALOE资料分析了爆发性增温过程中臭氧以及其它微量气体体积混合比分布的变化，分析表明：爆发性增温的过程中，高纬地区臭氧混合比增加的同时，中纬度地区臭氧混合比减少，通过合成分析臭氧的这种变化特征得到了验证；利用计算的剩余环流计算了爆发性增温过程中臭氧的净输送量，通过行星波的变化以及剩余环流的动力输送作用综合分析了爆发性增温过程中臭氧分布的变化，解释了增温过程中臭氧增加的动力输送机制。第五，利用NCEP资料通过分析北半球环状模(Northern Annular Mode)与SSW的关系，然后讨论了NAM变化与东亚急流和东亚大槽的关系，进而探讨爆发性增温对东亚急流和东亚大槽的影响。结果表明：爆发性增温的发生使东亚大槽加强，增温的下传使其对东亚大槽的影响南移，因此爆发性增温对东亚气候预测有参考价值。最后还总结了本论文工作的不足之处，对下一步应进行的工作提出了设想。更多还原

【Abstract】 Stratospheric Sudden Warming (SSW) is one of the most important characteristics in the stratosphere. A series of researches about the circulation variations of SSW and its relation with planetary wave have been done at home and abroad all the while and they gradually become a highlight and a frontier problem. In order to investigate the dynamical characteristics of SSW, the influence of SSW on the content and distribution of trace gases and the impact of SSW on the troposphere, on the basis of the data statistic analysis of the spatial and temporal distribution of SSW, E-P flux during SSW was calculated and planetary wave activity and variations during SSW was discussed; the residual meridional circulation was calculated and the transient characteristics of residual meridional circulation during SSW and the dynamical transport of ozone by the residual meridional circulation were studied, the variations of some other trace gases’ distribution during SSW were analyzed by using HALOE; the possible influence of SSW on the climate especially over East Asia via NAM was investigated. The following results and new recognition were obtained.Firstly, by analyzing the NCEP data, statistic characteristics of SSW are obtained: the frequency of SSW showed mensal feature and it usually occurred in March; during the period of SSW, the location of the wanning center of SSW in the Northern Hemisphere changed with height and it has an obvious local property at each level, SSW often occurred foremost at upper level, and then extended and transported from upper levels to lower levels with the warming center also shifting, at upper level the warming center firstly occurred in the East Hemisphere, with SSW transporting toward lower levels, the warming center shifted gradually to the Western Hemisphere anticlockwise pass through the 180°meridian plane; When SSW took place, the temperature changed not only in the high latitude regions , but also in the middle-low latitude regions, i.e. when the temperature rises in the high latitude regions , it decreases in the low latitude regions; SSW’s characteristics of the Southern Hemisphere in the September 2002 resembled that of the North Hemisphere.Secondly, the harmonics analysis of geopotential height fields was taken during SSW by using NCEP, the results showed that the planetary wave activity during SSW was not completely the same as Labitzke indicated, in spite of that the planetary wave of wave-number 1 unusually grows in the pre-SSW period and destroyed during SSW, the planetary wave of wave-number 2 has different feature in process of SSW. Corresponding with different planetary wave activity, breakdown of polar vortex was different. Planetary wave activity show in the following three types: (1), the planetary wave of wave-number 2 in the pre-SSW period is very weak, it unusually grows too stronger in the mid-SSW period. In this type the polar vortex breaks down and splits into two cyclonic centers; (2), the planetary wave of wave-number 2 in the pre-SSW period is correspondingly stronger, nevertheless, in the mid-SSW period, both planetary wave of wave-number 1 and wave-number 2 are distinctly weak, at the same time, the polar vortex moves outside of the polar region, but does not breakdown ; (3), planetary wave of wave-number 2 in the pre-SSW period is not very strong, while it develops slightly in the mid-SSW period, however, it can not surpass planetary wave of wave-number 1 in any case, simultaneously, the polar vortex firstly moves out from the polar region and then asymmetric distortion in form occurs. According to E-P flux, three types of planetary wave activity were discussed and the results showed that no matter what type of planetary wave of wave-number 2, it was in favor of the development of SSW.Thirdly, the transient residual meridional circulation was calculated during SSW via transformed Eulerian-mean thermodynamical equation and continuity equation by using ECMWF data for the composite analysis, and the general characteristics of residual meridional circulation during SSW was obtained, at the same time, the variation of the transient residual meridional circulation in the high latitude regions was analyzed during SSW. The results showed that the transient residual meridionalvelocity (?) at 10hPa～2hPa levels at the beginning of SSW changed gradually from southward to northward and northward wind turned stronger with SSW getting stronger , its intension increased with the increasing height, when SSW got weak, it slowly came back to southward wind with its intension stronger than that of pre-SSW period; the transient residual vertical velocity (?) at 10hPa～2hPa levels at the beginning of SSW changed gradually from weak ascending to sinking and its sinking became more stronger as SSW developing. When SSW became weak, it slowly came back to ascending with its intension stronger than that of pre-SSW period. The comparison between the transient residual meridional circulations which calculated with the term of wave heating or omitted wave heating, and the results showed that the term of wave heating in the upper stratosphere in the Polar Regions influenced transient residual meridional circulation and it was worth to be considered.Fourthly, the analysis of the distribution of ozone and other trace gases mixing ratio during SSW by using ECMWF data combining HALOE data showed that ozone mixing ratio in the high latitude increased during SSW with ozone mixing ratio decreasing in the middle latitude and this was validated by composite analysis; the net transportation of zone was calculated by using the calculated residual meridional circulation, the variation of ozone distribution was comprehensive analyzed according to the variation of planetary wave and dynamical transport of residual meridional circulation, therefore, mechanism of dynamical transportation about the increase of ozone was explained during SSW.Fifthly, by analyzing the relationship between Northern Annular Mode (NAM) and SSW and then discussing linkage between NAM and both East Asian jet and East Asian trough, the possible influence of SSW on East Asian jet and East Asian trough was investigated. The results showed that East Asian trough strengthened during SSW occurred, the influenced regions of East Asian trough shifted toward south with SSW transporting from upper to lower levels, thus, SSW has reference value for forecasting of East Asian climate.At last, we summed up the limitations of this paper and conceive the further work.更多还原