 |
| Titel |
Trends and variability in the upper troposphere/lower stratosphere 1990-2008: Insights from stratospheric water vapour |
| VerfasserIn |
S. Fueglistaler, P. H. Haynes, Y. Liu, A. Simmons, W. G. Read, G. Stiller |
| Konferenz |
EGU General Assembly 2009
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250028087
|
|
|
|
|
|
| Zusammenfassung |
| Stratospheric water vapour strongly affects Earth’s radiation budget, and plays an important
role for stratospheric chemistry. The processes that control its variability and long-term trends
remain a topic of debate despite significant progress in our understanding of the processes
controlling dehydration in the tropical tropopause layer (TTL). Here, we combine
measurements of stratospheric water vapour from HALOE (1991-2005), MIPAS
(2002-present) and MLS (2004-present) to derive a timeseries of water mixing ratios of air
entering the stratosphere. We use trajectory calculations based on the newly available
reanalysis data ERA-Interim provided by ECMWF to estimate water vapour concentrations at
entry into the stratosphere. We show that this Lagrangian approach successfully reproduces
observations, including a sharp drop in mid-2000 and a prolonged period of dryness
thereafter. The successful reproduction of observations allows identification of the processes
that control variability and trends. It is shown that stratospheric water vapour is a very
sensitive indicator of changes in the global climate system that affect conditions, i.e.
temperature structure and circulation, in the TTL, and as such elucidates connections in
the climate system that may be far less evident in other tracer or meteorological
data. |
|
|
|
|
|
|