Articles | Volume 16, issue 4
https://doi.org/10.5194/acp-16-2207-2016
https://doi.org/10.5194/acp-16-2207-2016
Research article
 | 
25 Feb 2016
Research article |  | 25 Feb 2016

Water vapour variability in the high-latitude upper troposphere – Part 2: Impact of volcanic eruptions

Christopher E. Sioris, Jason Zou, C. Thomas McElroy, Chris D. Boone, Patrick E. Sheese, and Peter F. Bernath

Abstract. The impact of volcanic eruptions on water vapour in the high-latitude upper troposphere is studied using deseasonalized time series based on observations by the Atmospheric Chemistry Experiment (ACE) water vapour sensors, namely MAESTRO (Measurements of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation) and the Fourier Transform Spectrometer (ACE-FTS). The two eruptions with the greatest impact on the high-latitude upper troposphere during the time frame of this satellite-based remote sensing mission are chosen. The Puyehue–Cordón Caulle volcanic eruption in June 2011 was the most explosive in the past 24 years and is shown to be able to account for the observed (50 ± 12) % increase in water vapour in the southern high-latitude upper troposphere in July 2011 after a minor adjustment for the simultaneous influence of the Antarctic oscillation. Eyjafjallajökull erupted in the spring of 2010, increasing water vapour in the upper troposphere at northern high latitudes significantly for a period of  ∼  1 month. These findings imply that extratropical volcanic eruptions in windy environments can lead to significant perturbations to high-latitude upper tropospheric humidity mostly due to entrainment of lower tropospheric moisture by wind-blown plumes. The Puyehue–Cordón Caulle eruption must be taken into account to properly determine the magnitude of the trend in southern high-latitude upper tropospheric water vapour over the last decade.

Short summary
This paper shows that volcanic eruptions occurring at higher latitudes in windy environments can lead to significant perturbations to upper tropospheric (UT) humidity mostly due to entrainment of lower tropospheric moisture by wind-blown plumes. This research was performed for the purpose of determining long-term trends in high-latitude UT water vapour. The steps involve building a monthly climatology and using it to deseasonalize the time series. Large observed anomalies are then studied.
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