SHARP-WV Phase II
The explanation of recent stratospheric H2O concentration changes based on extended ground based and satellite time series in conjunction with respective model studies, and a reliable assessment of future H2O concentrations based on improved understanding of the relevant processes in the past are a key issue for SHARP-WV in Phase II. Recent research work has focussed on phase change processes during transport of water vapour through the tropopause, and regional analysis of uplift processes (West Pacific, monsoon regions). Within SHARP we will extend studies related to these topics by putting some emphasis on the analysis of HDO data sets, since deuterated water vapour keeps a phase change record of the air mass. With respect to regional processes, we will focus on uplift processes in longitudinal regions in the tropics, or the Asian, African, and American monsoon systems. The data records of the new satellite instruments are dense enough to allow such a regional analysis. As a third focus, we will re-assess observational data and model results (in particular from a model run nudged to ERA-Interim data) related to re-assessed 30-year Boulder data record which became available recently, and the drop in water vapour abundance in 2000/2001 which is not yet fully understood. Finally, within SHARP we will investigate the correlation between water vapour and methane in the light of the somewhat unexpected changes of methane growth observed during the last 10 to 15 years.