Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

Journal metrics

  • IF value: 5.509 IF 5.509
  • IF 5-year value: 5.689 IF 5-year 5.689
  • CiteScore value: 5.44 CiteScore 5.44
  • SNIP value: 1.519 SNIP 1.519
  • SJR value: 3.032 SJR 3.032
  • IPP value: 5.37 IPP 5.37
  • h5-index value: 86 h5-index 86
  • Scimago H index value: 161 Scimago H index 161
Volume 18, issue 11 | Copyright

Special issue: Water vapour in the upper troposphere and middle atmosphere:...

Special issue: The Modular Earth Submodel System (MESSy) (ACP/GMD inter-journal...

Atmos. Chem. Phys., 18, 8331-8351, 2018
https://doi.org/10.5194/acp-18-8331-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

Research article 14 Jun 2018

Research article | 14 Jun 2018

Trend differences in lower stratospheric water vapour between Boulder and the zonal mean and their role in understanding fundamental observational discrepancies

Stefan Lossow1, Dale F. Hurst2, Karen H. Rosenlof2, Gabriele P. Stiller1, Thomas von Clarmann1, Sabine Brinkop3, Martin Dameris3, Patrick Jöckel3, Doug E. Kinnison4, Johannes Plieninger1, David A. Plummer5, Felix Ploeger6, William G. Read7, Ellis E. Remsberg8, James M. Russell9, and Mengchu Tao6 Stefan Lossow et al.
  • 1Karlsruhe Institute of Technology, Institute for Meteorology and Climate Research, Hermann-von-Helmholtz-Platz 1, 76344 Leopoldshafen, Germany
  • 2NOAA Earth System Research Laboratory, Global Monitoring Division, 325 Broadway, Boulder, CO 80305, USA
  • 3Deutsches Zentrum für Luft- und Raumfahrt (DLR), Institut für Physik der Atmosphäre, 82234 Oberpfaffenhofen-Wessling, Germany
  • 4University of Colorado, Atmospheric Chemistry Observations & Modeling Laboratory, P.O. Box 3000, Boulder, CO 80305-3000, USA
  • 5Environment and Climate Change Canada, Climate Research Branch, 550 Sherbrooke ouest, Montréal, Québec H3A 1B9, Canada
  • 6Forschungszentrum Jülich, Institute for Energy and Climate Research: Stratosphere (IEK–7), Leo-Brandt-Straße, 52425 Jülich, Germany
  • 7Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
  • 8NASA Langley Research Center, 21 Langley Boulevard, Hampton, VA 23681, USA
  • 9Hampton University, Center for Atmospheric Sciences, 23 Tyler Street, Hampton, VA 23668, USA

Abstract. Trend estimates with different signs are reported in the literature for lower stratospheric water vapour considering the time period between the late 1980s and 2010. The NOAA (National Oceanic and Atmospheric Administration) frost point hygrometer (FPH) observations at Boulder (Colorado, 40.0°N, 105.2°W) indicate positive trends (about 0.1 to 0.45ppmv decade−1). On the contrary, negative trends (approximately −0.2 to −0.1ppmv decade−1) are derived from a merged zonal mean satellite data set for a latitude band around the Boulder latitude. Overall, the trend differences between the two data sets range from about 0.3 to 0.5ppmv decade−1, depending on altitude. It has been proposed that a possible explanation for these discrepancies is a different temporal behaviour at Boulder and the zonal mean. In this work we investigate trend differences between Boulder and the zonal mean using primarily simulations from ECHAM/MESSy (European Centre for Medium-Range Weather Forecasts Hamburg/Modular Earth Submodel System) Atmospheric Chemistry (EMAC), WACCM (Whole Atmosphere Community Climate Model), CMAM (Canadian Middle Atmosphere Model) and CLaMS (Chemical Lagrangian Model of the Stratosphere). On shorter timescales we address this aspect also based on satellite observations from UARS/HALOE (Upper Atmosphere Research Satellite/Halogen Occultation Experiment), Envisat/MIPAS (Environmental Satellite/Michelson Interferometer for Passive Atmospheric Sounding) and Aura/MLS (Microwave Limb Sounder). Overall, both the simulations and observations exhibit trend differences between Boulder and the zonal mean. The differences are dependent on altitude and the time period considered. The model simulations indicate only small trend differences between Boulder and the zonal mean for the time period between the late 1980s and 2010. These are clearly not sufficient to explain the discrepancies between the trend estimates derived from the FPH observations and the merged zonal mean satellite data set. Unless the simulations underrepresent variability or the trend differences originate from smaller spatial and temporal scales than resolved by the model simulations, trends at Boulder for this time period should also be quite representative for the zonal mean and even other latitude bands. Trend differences for a decade of data are larger and need to be kept in mind when comparing results for Boulder and the zonal mean on this timescale. Beyond that, we find that the trend estimates for the time period between the late 1980s and 2010 also significantly differ among the simulations. They are larger than those derived from the merged satellite data set and smaller than the trend estimates derived from the FPH observations.

Download & links
Publications Copernicus
Special issue
Download
Short summary
Trend estimates of lower stratospheric H2O derived from the FPH observations at Boulder and a merged zonal mean satellite data set clearly differ for the time period from the late 1980s to 2010. We investigate if a sampling bias between Boulder and the zonal mean around the Boulder latitude can explain these trend discrepancies. Typically they are small and not sufficient to explain the trend discrepancies in the observational database.
Trend estimates of lower stratospheric H2O derived from the FPH observations at Boulder and a...
Citation
Share