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| Titel |
MARS: A New Retrieval Scheme for Aircraft Remote Sensing Measurements |
| VerfasserIn |
Samuel Illingworth, Grant Allen, Martin Gallagher, Sebastian O'shea, Stuart Newman, Alan Vance, John Remedios, David Moore |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250081409
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| Zusammenfassung |
| The importance of aircraft in-situ measurements of GreenHouse Gases (GHG) and
trace gases is well understood, providing not only spatially resolved and accurate
concentration data for these gases, but also essential validation for many other types of
measurement, the most common being that from ground-based and satellite remote sensing
instrumentation. The role of airborne remote sensing instruments is equally important
in building up an accurate understanding of the composition of the atmosphere,
providing far greater spatial coverage than their ground-based equivalents, whilst in
the thermal infrared, the opportunity to fly at relatively low altitudes allows for a
greater sensitivity towards the surface than that provided by any current satellite
measurements.
The UK Met Office Airborne Research Interferometer Evaluation System (ARIES) is a
Fourier transform spectrometer that is mounted on the NERC Facility for Airborne
Atmospheric Measurements (FAAM) aircraft, and which measures incoming radiation over a
large wavenumber range (550-3000 cm-1), at high spectral resolution (~0.7 cm-1
unapodised). This level of precision, combined with a low NEDT (0.2 K for 1-minute
averaged spectra) allows for the detection of a wide variety of important GHG and trace
gases, the concentrations of which can be derived from the measured spectra by use of
retrieval theory.
This work presents a new Optimal Estimation Method (OEM) retrieval of GHG and trace
gas vertically resolved profiles in the mid-troposphere and planetary boundary layer, from
observations of the ARIES instrument. The Manchester ARIES Retrieval Scheme (MARS)
utilizes a large subset of high-accuracy and high-precision auxiliary datasets to produce a
well-characterized retrieval product. First retrieval results, as well as a validation of these
results with in-situ measurements are to be presented, with error characterization suggesting
that the retrieval bias is of the order of 1-2%.
As well as presenting the results from this particular study, we shall also discuss the issue
of vertical sensitivity of nadir IR sensors in the troposphere for various trace gases, as well as
the importance that the selection of auxiliary data sets, in particular the influence of the a
priori, play in the retrieval process. |
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