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Study on the dehydration processes in the tropical tropopause layer

热带对流层顶层脱水过程的研究

基本信息

批准号：
15204043
负责人：
HASEBE Fumio
金额：
$ 28.04万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

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.

在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，目的是研究热带对流层顶层（TTL）的脱水过程和估计热带平流层低层水汽的长期趋势。到目前为止还没有发现明显的水汽趋势。沿着TTL的空中轨迹选择观测站在塔拉瓦、Biak、万隆、Kototabang和河内。还利用了“未来”号游轮的机会。在空气中保留的水量与观测前相应气团经历的冷度之间有很好的对应关系。在水汽“匹配”中，同一气团沿着轨迹被观测两次或更多次，这有助于使这种估计更可靠。目前正在进行分析，特别注意估计探空数据的观测不确定性，客观识别“匹配”对，探测穿透性对流云，以及考虑气象领域可能存在的偏差。激光雷达观测亚可见光卷云（SVC），以补充探空观测。这将使我们能够在水汽剖面中推断出SVC的高度，并了解SVC中冰粒周围的大气状况。对于过饱和程度在SVC中显示出有趣变化的情况，正在进行详细的调查。另一方面，在模型研究中，建立了一个使用质量加权等熵纬向平均值的新框架。用它来研究运输在臭氧总量季节变化中的作用。研究了同化气象变量变化对臭氧模拟的影响。这些结果将在未来的后续研究中得到扩展。