Climate and Dynamics
A drop in upper tropospheric humidity in autumn 2001, as derived from radiosonde measurements at Uccle, Belgium
Article first published online: 26 OCT 2010
Copyright 2010 by the American Geophysical Union.
Journal of Geophysical Research: Atmospheres (1984–2012)
Volume 115, Issue D20, 27 October 2010
How to Cite
2010), A drop in upper tropospheric humidity in autumn 2001, as derived from radiosonde measurements at Uccle, Belgium, J. Geophys. Res., 115, D20114, doi:10.1029/2009JD013587., and (
- Issue published online: 26 OCT 2010
- Article first published online: 26 OCT 2010
- Manuscript Accepted: 21 JUN 2010
- Manuscript Revised: 9 JUN 2010
- Manuscript Received: 23 NOV 2009
- water vapor;
- climate change
 Simulations of climate models predict a doubling of the amount of upper tropospheric water vapor by the end of this century, caused by the increasing concentrations of greenhouse gases. Observations indicate that the tropopause height has increased by several hundred meters since 1979. In this paper, we verify and link these two results by carrying out a time series analysis on a uniform database of corrected radiosonde vertical profiles gathered at Uccle, Belgium, and covering the 1990–2007 time period. The most remarkable finding of this trend analysis is a significant drop in upper tropospheric humidity (UTH) around autumn 2001, which marks an end to the upper tropospheric moistening of the precedent decade. This UTH drop in autumn 2001 coexists with a sudden lifting and cooling of the tropopause and with a significant stretch-out of the free troposphere. Therefore, we conclude that these autumn 2001 trends are certainly associated with the dynamical behavior of the troposphere, triggered by the surface warming. Links with the solar variability and the lower stratosphere were investigated but could not be established definitely.