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Titel |
The performance of Aeolus in heterogeneous atmospheric conditions using high-resolution radiosonde data |
VerfasserIn |
X. J. Sun, R. W. Zhang, G. J. Marseille, A. Stoffelen, D. Donovan, L. Liu, J. Zhao |
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. 8 ; Nr. 7, no. 8 (2014-08-26), S.2695-2717 |
Datensatznummer |
250115882
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Publikation (Nr.) |
copernicus.org/amt-7-2695-2014.pdf |
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Zusammenfassung |
The European Space Agency Aeolus mission aims to measure wind profiles from space. A major
challenge is to retrieve high quality winds in heterogeneous atmospheric
conditions, i.e. where both the atmospheric dynamics and optical properties
vary strongly within the sampling volume. In preparation for launch we aim
to quantify the expected error of retrieved winds from atmospheric
heterogeneity, particularly in the vertical, and develop algorithms for wind
error correction, as part of the level-2B processor (L2Bp).
We demonstrate that high-resolution data from radiosondes provide valuable
input to establish a database of collocated wind and atmospheric optics at
10 m vertical resolution to simulate atmospheric conditions along
Aeolus' lines of sight. The database is used to simulate errors of Aeolus
winds retrieved from the Mie and Rayleigh channel signals. The non-uniform
distribution of molecules in the measurement bin introduces
height assignment errors in Rayleigh channel winds up to 2.5% of the
measurement bin size in the stratosphere which translates to 0.5 m s−1
bias for typical atmospheric conditions, if not corrected. The presence of
cloud or aerosol layers in the measurement bin yields biases in Mie channel
winds which cannot be easily corrected and mostly exceed the mission
requirement of 0.4 m s−1. The collocated Rayleigh channel wind solution
is generally preferred because of smaller biases, in particular for
transparent cloud and aerosol layers with one-way transmission above 0.8.
The results show that Aeolus L2Bp, under development, can be improved by the
estimation of atmosphere optical properties to correct for height assignment
errors and to identify wind solutions potentially detrimental when used in
Numerical Weather Prediction. |
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