naa a22 4500 530098431 20181026074613.0 cr unu---uuuuu 181026s2014 xx s 000 0 eng 10.3929/ethz-b-000091942 doi 10.5194/acp-14-10803-2014 doi (ETHRESEARCH)oai:www.research-collection.ethz.ch:20.500.11850/91942 Comparison of Fast In situ Stratospheric Hygrometer (FISH) measurements of water vapor in the upper troposphere and lower stratosphere (UTLS) with ECMWF (re)analysis data [Elektronische Daten] [Anne Kunz, Nicole Spelten, Paul Konopka, Rolf Müller, Richard M. Forbes, Heini; id_orcid 0000-0001-9674-4837 Wernli] Atmos. chem. phys. Open access ethresearch An evaluation of water vapor in the upper troposphere and lower stratosphere (UTLS) of the ERA-Interim, the global atmospheric reanalysis produced by the European Centre for Medium-Range Weather Forecasts (ECMWF), is presented. Water vapor measurements are derived from the Fast In situ Stratospheric Hygrometer (FISH) during a large set of airborne measurement campaigns from 2001 to 2011 in the tropics, midlatitudes and polar regions, covering isentropic layers from 300 to 400K (5-18km). The comparison shows around 87% of the reanalysis data are within a factor of 2 of the FISH water vapor measurements and around 30% have a nearly perfect agreement with an over- and underestimation lower than 10%. Nevertheless, strong over- and underestimations can occur both in the UT and LS, in particularly in the extratropical LS and in the tropical UT, where severe over- and underestimations up to 10 times can occur. The analysis data from the evolving ECMWF operational system is also evaluated, and the FISH measurements are divided into time periods representing different cycles of the Integrated Forecast System (IFS). The agreement with FISH improves over the time, in particular when comparing water vapor fields for time periods before 2004 and after 2010. It appears that influences of tropical tropospheric and extratropical UTLS processes, e.g., convective and quasi-isentropic exchange processes, are particularly challenging for the simulation of the UTLS water vapor distribution. Both the reanalysis and operational analysis data show the tendency of an overestimation of low water vapor mixing ratio (⪅10ppmv) in the LS and underestimation of high water vapor mixing ratio (⪆300ppmv) in the UT. Creative Commons Attribution 3.0 Unported http://creativecommons.org/licenses/by/3.0 ethresearch Kunz Anne joint author Spelten Nicole joint author Konopka Paul joint author Müller Rolf joint author Forbes Richard M. joint author Wernli Heini; id_orcid 0000-0001-9674-4837 joint author Atmospheric Chemistry and Physics Göttingen : Copernicus 14, pp. 10803-10822 1680-7375 http://hdl.handle.net/20.500.11850/91942 text/html WWW-Backlink auf das Repository (Open access) 1 Journal Article ethresearch ETHRESEARCH 856 40 http://hdl.handle.net/20.500.11850/91942 text/html WWW-Backlink auf das Repository (Open access) ETHRESEARCH 700 1- Kunz Anne joint author ETHRESEARCH 700 1- Spelten Nicole joint author ETHRESEARCH 700 1- Konopka Paul joint author ETHRESEARCH 700 1- Müller Rolf joint author ETHRESEARCH 700 1- Forbes Richard M. joint author ETHRESEARCH 700 1- Wernli Heini; id_orcid 0000-0001-9674-4837 joint author ETHRESEARCH 773 0- Atmospheric Chemistry and Physics Göttingen : Copernicus 14, pp. 10803-10822 1680-7375 BK010053 XK010053 XK010000 ETHRESEARCH ETHRESEARCH ETHRESEARCH Journal Article Open access