Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 16, 4307-4321, 2016
https://doi.org/10.5194/acp-16-4307-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
07 Apr 2016
Variability of water vapour in the Arctic stratosphere
Laura Thölix1, Leif Backman1, Rigel Kivi2, and Alexey Yu. Karpechko3 1Climate Research, Finnish Meteorological Institute, Helsinki, Finland
2Arctic Research, Finnish Meteorological Institute, Sodankylä, Finland
3Arctic Research, Finnish Meteorological Institute, Helsinki, Finland
Abstract. This study evaluates the stratospheric water vapour distribution and variability in the Arctic. A FinROSE chemistry transport model simulation covering the years 1990–2014 is compared to observations (satellite and frost point hygrometer soundings), and the sources of stratospheric water vapour are studied. In the simulations, the Arctic water vapour shows decadal variability with a magnitude of 0.8 ppm. Both observations and the simulations show an increase in the water vapour concentration in the Arctic stratosphere after the year 2006, but around 2012 the concentration started to decrease. Model calculations suggest that this increase in water vapour is mostly explained by transport-related processes, while the photochemically produced water vapour plays a relatively smaller role. The increase in water vapour in the presence of the low winter temperatures in the Arctic stratosphere led to more frequent occurrence of ice polar stratospheric clouds (PSCs) in the Arctic vortex. We perform a case study of ice PSC formation focusing on January 2010 when the polar vortex was unusually cold and allowed large-scale formation of PSCs. At the same time a large-scale persistent dehydration was observed. Ice PSCs and dehydration observed at Sodankylä with accurate water vapour soundings in January and February 2010 during the LAPBIAT (Lapland Atmosphere–Biosphere facility) atmospheric measurement campaign were well reproduced by the model. In particular, both the observed and simulated decrease in water vapour in the dehydration layer was up to 1.5 ppm.

Citation: Thölix, L., Backman, L., Kivi, R., and Karpechko, A. Yu.: Variability of water vapour in the Arctic stratosphere, Atmos. Chem. Phys., 16, 4307-4321, https://doi.org/10.5194/acp-16-4307-2016, 2016.
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