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| Titel |
Atmospheric composition and thermodynamic retrievals from the ARIES airborne FTS system – Part 1: Technical aspects and simulated capability |
| VerfasserIn |
S. M. Illingworth, G. Allen, S. Newman, A. Vance, F. Marenco, R. C. Harlow, J. Taylor, D. P. Moore, J. J. Remedios |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 7, no. 4 ; Nr. 7, no. 4 (2014-04-30), S.1133-1150 |
| Datensatznummer |
250115706
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| Publikation (Nr.) |
 copernicus.org/amt-7-1133-2014.pdf |
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| Zusammenfassung |
In this study we present an assessment of the retrieval capability of the
Airborne Research Interferometer Evaluation System (ARIES): an airborne
remote-sensing Fourier transform spectrometer (FTS) operated on the UK
Facility for Airborne Atmospheric Measurement (FAAM) aircraft. Simulated
maximum a posteriori retrievals of partial column trace gas concentrations,
and thermodynamic vertical profiles throughout the troposphere and planetary
boundary layer have been performed here for simulated infrared spectra
representative of the ARIES system operating in the nadir-viewing geometry.
We also describe the operational and technical aspects of the pre-processing
necessary for routine retrieval from the FAAM platform and the selection and
construction of a priori information. As exemplars of the capability of the
ARIES retrieval system, simulated retrievals of temperature, water vapour
(H2O), carbon monoxide (CO), ozone (O3), and methane (CH4),
and their corresponding sources of error and potential vertical sensitivity,
are discussed for ARIES scenes across typical global environments.
The maximum Degrees of Freedom for Signal (DOFS) for the retrievals,
assuming a flight altitude of 7 km, were 3.99, 2.97, 0.85, 0.96, and 1.45
for temperature, H2O, CO, O3, and CH4, respectively, for the a
priori constraints specified. Retrievals of temperature display significant
vertical sensitivity (DOFS in the range 2.6 to 4.0 across the altitude
range) as well as excellent simulated accuracy, with the vertical
sensitivity for H2O also extending to lower altitudes (DOFS ranging
from 1.6 to 3.0). It was found that the maximum sensitivity for CO, O3,
and CH4 was approximately 1–2 km below the simulated altitudes in all
scenarios.
Comparisons of retrieved and simulated-truth partial atmospheric columns are
used to assess the capability of the ARIES measurement system. Maximum mean
biases (and bias standard deviations) in partial columns (i.e. below
aircraft total columns) were found to be +0.06 (±0.02 at 1σ)%,
+3.95 (±3.11)%, +3.74 (±2.97)%, −8.26 (±4.64)%,
and +3.01 (±2.61)% for temperature,
H2O, CO, O3, and CH4, respectively, illustrating that the
retrieval system performs well compared to an optimal scheme. The maximum
total a posteriori retrieval errors across the partial columns were also
calculated, and were found to be 0.20, 22.57, 18.22, 17.61,
and 16.42% for temperature, H2O, CO, O3, and CH4, respectively. |
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