A multi-instrument comparison of integrated water vapour measurements at a high latitude site

Publikation: Forskning - peer-reviewTidskriftsartikel

Stefan Buehler ; S. Östman ; C. Melsheimer ; Gerrit Holl ; Salomon Eliasson ; V.O. John ; T. Blumenstock ; F. Hase ; G. Ekgered ; U. Raffalski ; T. Nasuno ; M. Satho ; Mathias Milz ; Jana Mendrok

  • Luleå tekniska universitet
  • Institute of Environmental Physics, University of Bremen
  • Met Office Hadley Centre, Exeter
  • Forschungszentrum Karlsruhe, Institut für Meteorologie und Klimaforschung Karlsruhe
  • Chalmers University of Technology, Department of Earth and Space Sciences
  • Swedish Institute of Space Physics / Institutet för rymdfysik
  • Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology, Yokohama
  • Atmosphere and Ocean Research Institute, University of Tokyo
We compare measurements of integrated water vapour (IWV) over a subarctic site (Kiruna, Northern Sweden) from five different sensors and retrieval methods: Radiosondes, Global Positioning System (GPS), ground-based Fourier-transform infrared (FTIR) spectrometer, ground-based microwave radiometer, and satellite-based microwave radiometer (AMSU-B). Additionally, we compare also to ERA-Interim model reanalysis data. GPS-based IWV data have the highest temporal coverage and resolution and are chosen as reference data set. All datasets agree reasonably well, but the ground-based microwave instrument only if the data are cloud-filtered. We also address two issues that are general for such intercomparison studies, the impact of different lower altitude limits for the IWV integration, and the impact of representativeness error. We develop methods for correcting for the former, and estimating the random error contribution of the latter. A literature survey reveals that reported systematic differences between different techniques are study-dependent and show no overall consistent pattern. Further improving the absolute accuracy of IWV measurements and providing climate-quality time series therefore remain challenging problems.
TidskriftAtmospheric Chemistry and Physics
Sidor (från-till)10925-10943
StatusPublicerad - 2012