Study on the dehydration processes in the tropical tropopause layer

为了研究热带对流层顶（TTL）的脱水过程和估算热带平流层低层水汽的长期变化趋势，分别于2003年12月、2004年12月至2005年1月和2005年12月至2006年1月进行了臭氧和水汽探空观测。到目前为止，尚未探测到明显的水汽趋势。在TTL的空中轨迹上选择了塔拉瓦、比亚克、万隆、科托塔邦和河内的观测站。“米拉伊”号邮轮的机会也被抓住了。在空气中保留的水量和相应的气团在观测之前经历的寒冷度之间发现了良好的对应关系。水蒸气“匹配”，其中相同的空气团被观察到两次或更多次沿着的轨迹是有用的，使这种估计更可靠。目前正在进行分析，特别注意估计探测器数据的观测不确定性，客观确定“匹配”对，探测穿透性对流云，并考虑气象领域可能存在的偏差。激光雷达观测的亚可见卷云（SVC）也补充探空观测。这将使我们能够推断SVC的高度在水汽廓线和了解周围的大气条件SVC的冰粒。详细的调查正在进行的情况下，过饱和的程度显示有趣的变化，在SVC。另一方面，对于模式研究，建立了一个新的框架，使用质量加权等熵纬向平均。它被用来研究输送在臭氧总量季节变化中的作用。还研究了变化的同化气象变量对臭氧模拟的影响。这些结果将在今后的后续研究中得到推广。

Ozone and water vapor sonde observations were conducted in December 2003, December 2004 to January 2005, and December 2005 to January 2006 for the purpose of studying the dehydration processes in the tropical tropopause layer (TTL) and estimating long-term trend of water vapor in the tropical lower stratosphere. Appreciable water vapor trend has not been detected so far. Observational stations were chosen along the air trajectory in the TTL at Tarawa, Biak, Bandung, Kototabang, and Hanoi. The opportunity of "Mirai" cruise was also taken. There found good correspondence between the retained amount of water in the air and the coldness the corresponding air mass experienced prior to observation. Water vapor "match" in which the same air parcel is observed twice or more along the trajectories is useful to make such estimates more reliable. Analyses are currently under way paying special attention to the estimation of observational uncertainty in the sonde data, objective identification of "match" pairs, detection of penetrating convective clouds, and consideration of possible bias in the meteorological field. Lidar observations of subvisible cirrus clouds (SVC) were also made to supplement sonde observations. It will enable us to infer the altitude of SVC in the water vapor profiles and to know the atmospheric condition surrounding the ice particle in SVC. Detailed investigation is under way for the case where the degree of super saturation shows interesting change in the SVC. For the modeling study, on the other hand, a new framework with the use of mass-weighted isentropic zonal mean was established. It was used to study the role of transport in the seasonal variation of total ozone. The impact of changing assimilated meteorological variables on ozone simulations is also investigated. These results will be extended in the successive studies in the future.