Study on the dehydration processes in the tropical tropopause layer by measurements of minor constituents and numerical modeling

本研究的目的是更好地了解在热带对流层顶层的dehydrationprocess和监测热带低平流层的水汽趋势进行无线电探空观测，在西部的水热带太平洋的冰点湿度计。该项目的独特之处在于水汽“匹配”的协调观测策略，即操作一个站点网络两次或更多次捕获相同的空气包，以量化所观测的特定空气的脱水量。从积累的资料中得到的主要结果是：观测气团的水量与相应气团沿沿着的饱和水混合比之间有密切的关系，它反映了气象条件，如站的位置、等熵层、季节和ENSO状态。探测器剖面的具体特征，如相对湿度的跳跃，可以作为单个探测基础上的空气团起源的差异来追踪。这一事实为我们提供了一些信心，在确定“匹配”对，尽管在这样的尝试的困难。与激光雷达观测到的卷云分布的水廓线的比较显示出有趣的结果的凝结和过饱和的空气。其中一些结果已在国际会议上提出，并发表在文献中。不幸的是，由于美国的预算问题，与TC4的合作观测没有进行。然而，我们的数据有助于验证卫星观测结果。最后，值得一提的是，我们已经用莱曼α湿度计进行了一些试飞，并正在准备一些同化运行，将观测数据纳入当前研究的未来扩展。

The purpose of the present study is to better understand the dehydrationprocesses in the TropicalTropopause Layer and to monitor the water vapor trend in the tropical lower stratosphere by conducting radiosonde observations using frostpoint hygrometers in the western for the water tropical Pacific. Uniqueness of this project lies in the coordinated observation strategy for the water vapor "match", that is, to operate a network of stations to catch the same air parcels twice or more toquantify the dehydrated amount for the specific air observed. The main findings so far obtained from the accumulated data are: There are close relationships between the water amount of the observed air parcel and the saturation water mixing ratio along the trajectories of the corresponding air parcel reflecting the meteorological conditions such as the location of the stations, isentropic levels, season and ENSOstatus. Specific features of the sonde profiles such as a jump in the relative humidity could be traced as a difference in the origin of the air parcel on an individual sounding basis. This fact provides us some confidence in identifying the "match" pairs in spite of the difficulties in such an attempt. Comparisons of the water profiles with cirrus distributions observed by lidars show interesting results on the condensation and super saturation for the air. Some of these results have been presented in international conferences and published in the literature. Unfortunately, the collaborative observations with TC4 did not take place due to the budget problem in US. However, our data have contributed to the validation of satellite observations. Finally it will be worth mentioning that we have conducted some test flights with Lyman alpha hygrometer and are preparing some assimilation runs by incorporating observed data for the future extension of the current study.