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| Titel |
CO2 and CH4 total column retrievals: The study of co-registration errors in multiband IR spectroscopes in support of future satellite missions |
| VerfasserIn |
Frans Alkemade, André Galli, Hartmut Boesch, Heinrich Bovensmann, Michael Buchwitz, Ramiro Checa-Garcia, André Butz, Ilse Aben, Otto Hasekamp, Jochen Landgraf |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250098927
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| Publikation (Nr.) |
 EGU/EGU2014-14651.pdf |
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| Zusammenfassung |
| Measuring atmospheric composition is a central objective for monitoring climate change and
understanding human impact on the environment. One of the targets of future Earth observing
satellite missions is quantifying natural and anthropogenic sources and sinks of Carbon
Dioxide (CO2) and Methane (CH4). These missions, like CarbonSat, Sentinel-5 and its
precursor S5-P, use a multi-band retrieval approach to characterize atmospheric scattering by
aerosols and cirrus. The measurements from a grating spectrometer in which different optical
modules measure different spectral bands may typically suffer from co-registration errors,
due to a spatial mis-alignement of the different optical channels. Here, we study the effect
that a mis-alignement of the different spectral bands would have on the retrieval
performance for a space-borne multiband spectroscope collecting solar backscatter
absorption spectra in the near and shortwave infrared. We only take into account
retrieval errors due to spatial heterogeneity of cirrus clouds. Since cloudy scenes are
commonly filtered out, the remaining co-registration errors in the retrieved CO2
and CH4 are expected to arise mostly from differing cirrus optical depth between
different bands. This may cause an incorrect fit of the aerosol size distribution.
To study the impact of this error on the retrieval accuracy of CO2 and CH4, we
performed retrieval simulations for an ensemble of synthetic scenarios covering
a typical range of cirrus configurations, derived from LIDAR observations. Our
study in particular aims at supporting the best selection of instrument properties
of new sensors such as Sentinel-5, S5-P and the CarbonSat mission and provides
insight into critical aspects to be considered in the design of future satellite missions. |
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