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| Titel |
Biases caused by the instrument bandwidth and beam width on simulated brightness temperature measurements from scanning microwave radiometers |
| VerfasserIn |
V. Meunier, U. Löhnert, P. Kollias, S. Crewell |
| 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 ; 6, no. 5 ; Nr. 6, no. 5 (2013-05-07), S.1171-1187 |
| Datensatznummer |
250017886
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| Publikation (Nr.) |
 copernicus.org/amt-6-1171-2013.pdf |
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| Zusammenfassung |
| More so than the traditional fixed radiometers, the scanning radiometer
requires a careful design to ensure high quality measurements. Here the
impact of the radiometer characteristics (e.g., antenna beam width and receiver
bandwidth) and atmospheric propagation (e.g. curvature of the Earth and
vertical gradient of refractive index) on scanning radiometer measurements are presented. A forward
radiative transfer model that includes all these effects to represent the
instrument measurements is used to estimate the biases. These biases are
estimated using differences between the measurement with and without these
characteristics for three commonly used frequency bands: K, V and W-band.
The receiver channel bandwidth errors are less important in K-band and
W-band. Thus, the use of a wider bandwidth to improve detection at low
signal-to-noise conditions is acceptable at these frequencies. The biases
caused by omitting the antenna beam width in measurement simulations are
larger than those caused by omitting the receiver bandwidth, except for
V-band where the bandwidth may be more important in the vicinity of
absorption peaks. Using simple regression algorithms, the effects of the
bandwidth and beam width biases in liquid water path, integrated water
vapour, and temperature are also examined. The largest errors in liquid water
path and integrated water vapour are associated with the beam width errors. |
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