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| Titel |
Water Vapour Profiles from SCIAMACHY Solar Occultation Measurements derived with Onion Peeling DOAS |
| VerfasserIn |
S. Noël, K. Bramstedt, A. Rozanov, H. Bovensmann, J. P. Burrows |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250023442
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| Zusammenfassung |
| Water vapour is the most important greenhouse gas and plays a key role in atmospheric
chemistry and transport. Most of the water vapour is located in the troposphere where it
significantly contributes to weather and climate. Because the tropopause acts as a cold trap,
the water vapour density in the stratosphere is significantly lower and decreases rapidly with
increasing altitude. However, the amount of stratospheric water vapour plays an important
role in the generation of Polar Stratospheric Clouds (PSCs), which in turn influence strongly
the amount of ozone in polar regions.
Trends in stratospheric water vapour are determined by methane oxidation, transport through
the tropopause and by the Brewer-Dobson circulation. To seperate the various effects there is
a clear need for global long term measurements of lower stratospheric water vapour, which
can be provided by satellite measurements.
A new retrieval method (called “Onion Peeling DOAS”) has been developed to derive water
vapour number density profiles from solar occultation measurements of the SCanning
Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY). This
method is intentionally kept simple and based on a combination of an onion peeling approach
with a modified DOAS (Differential Optical Absorption Spectroscopy) fit in the wavelength
region around 940Â nm. The resulting water vapour profiles currently cover the altitude range
15–50Â km.
Here, first retrieval results and comparisons of the SCIAMACHY profiles with water vapour
data provided by the Atmospheric Chemistry Explorer Fourier Transform Spectrometer
(ACE-FTS) and model data of the European Centre for Medium Range Weather Forecasts
(ECMWF) are shown. |
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