Journal Article

FZJ-2018-07121

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Intercomparison of midlatitude tropospheric and lower-stratospheric water vapor measurements and comparison to ECMWF humidity data

Kaufmann, S. (Corresponding author) ; Voigt, C. ; Heller, R. ; Jurkat-Witschas, T. ; Krämer, M.FZJ* ; Rolf, C.FZJ* ; Zöger, M. ; Giez, A. ; Buchholz, B. ; Ebert, V. ; Thornberry, T. ; Schumann, U.

2018
EGU Katlenburg-Lindau

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Please use a persistent id in citations: http://hdl.handle.net/2128/20455  doi:10.5194/acp-18-16729-2018

Abstract: Accurate measurement of water vapor in the climate-sensitive region near the tropopause is very challenging. Unexplained systematic discrepancies between measurements at low water vapor mixing ratios made by different instruments on airborne platforms have limited our ability to adequately address a number of relevant scientific questions on the humidity distribution, cloud formation and climate impact in that region. Therefore, during the past decade, the scientific community has undertaken substantial efforts to understand these discrepancies and improve the quality of water vapor measurements. This study presents a comprehensive intercomparison of airborne state-of-the-art in situ hygrometers deployed on board the DLR (German Aerospace Center) research aircraft HALO (High Altitude and LOng Range Research Aircraft) during the Midlatitude CIRRUS (ML-CIRRUS) campaign conducted in 2014 over central Europe. The instrument intercomparison shows that the hygrometer measurements agree within their combined accuracy (±10 % to 15 %, depending on the humidity regime); total mean values agree within 2.5 %. However, systematic differences on the order of 10 % and up to a maximum of 15 % are found for mixing ratios below 10 parts per million (ppm) H2O. A comparison of relative humidity within cirrus clouds does not indicate a systematic instrument bias in either water vapor or temperature measurements in the upper troposphere. Furthermore, in situ measurements are compared to model data from the European Centre for Medium-Range Weather Forecasts (ECMWF) which are interpolated along the ML-CIRRUS flight tracks. We find a mean agreement within ±10 % throughout the troposphere and a significant wet bias in the model on the order of 100 % to 150 % in the stratosphere close to the tropopause. Consistent with previous studies, this analysis indicates that the model deficit is mainly caused by too weak of a humidity gradient at the tropopause

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Contributing Institute(s):

1. Stratosphäre (IEK-7)

Research Program(s):

1. 244 - Composition and dynamics of the upper troposphere and middle atmosphere (POF3-244) (POF3-244)

Appears in the scientific report 2018

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Database coverage:
; ; ; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; DOAJ Seal ; IF >= 5 ; JCR ; NCBI Molecular Biology Database ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Web of Science Core Collection

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