This title appears in the Scientific Report : 2001 

Water vapor at the tropopause during the CRISTA 2 mission
Offermann, D.
Schaeler, B. / Riese, M. / Langfermann, M. / Jarisch, M. / Eidmann, G. / Schiller, C. / Smit, H. G. J. / Read, W. G.
Troposphäre; ICG-II
Journal of geophysical research / Atmospheres, 107 (2002) D23, S. CRI 4-1–CRI 4-18, 16
Washington, DC Washington, DC Union 2002
Journal Article
Chemie und Dynamik der Geo-Biosphäre
Journal of Geophysical Research 107
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[1] Water vapor mixing ratios at the tropopause are derived as a new Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA) data product from limb scan measurements of the second mission. Global maps are obtained on a daily basis. Data loss due to high clouds is found to be moderate. Good agreement with in situ airplane measurements (Fast In Situ Stratospheric Hygrometer (FISH)) is obtained for these Version 1 data. A number of different analyses are performed to show the research potential of the data product: the CRISTA data are compared to measurements of the Microwave Limb Sounder (MLS) instrument on the Upper Atmosphere Research Satellite (UARS). Version 4.9 climatology data and Version 5 coincident measurements are used. Good agreement of CRISTA and Version 4.9 data is obtained, whereas there are differences with respect to the Version 5.0 data. CRISTA finds vapor mixing ratios to be highly variable. Only a small part of this is instrumental. Variability is structured, and a scaling behavior is observed. Relation to convectively generated gravity waves is discussed. Relative humidity (RH) is determined on the basis of the CRISTA data. Suitability for supersaturation statistics is discussed and appears to be limited. CRISTA water vapor data are assimilated into a 3D transport model driven by UK Meteorological Office (UKMO) winds. Results are discussed in terms of meridional transports and atmospheric diffusivities. Diffusivities appear to be connected with the water vapor variances in a simple manner.