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| Titel |
A modification to the standard ionospheric correction method used in GPS radio occultation |
| VerfasserIn |
S. B. Healy, I. D. Culverwell |
| 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 ; 8, no. 8 ; Nr. 8, no. 8 (2015-08-21), S.3385-3393 |
| Datensatznummer |
250116536
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| Publikation (Nr.) |
 copernicus.org/amt-8-3385-2015.pdf |
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| Zusammenfassung |
| A modification to the standard bending-angle correction used in GPS
radio occultation (GPS-RO) is proposed. The modified approach should reduce
systematic residual ionospheric errors in GPS radio occultation
climatologies. A new second-order term is introduced in order to
account for a known source of systematic error, which is generally
neglected. The new term has the form κ(a) ×
(αL1(a)-αL2(a))2, where a is
the impact parameter and (αL1,
αL2) are the L1 and L2 bending angles,
respectively. The variable κ is a weak function of the impact
parameter, a, but it does depend on a priori ionospheric
information. The theoretical basis of the new term is examined. The
sensitivity of κ to the assumed ionospheric parameters is
investigated in one-dimensional simulations, and it is shown that
κ ≃ 10–20 rad−1. We note that the current
implicit assumption is κ=0, and this is probably adequate for
numerical weather prediction applications. However, the uncertainty
in κ should be included in the uncertainty estimates for the
geophysical climatologies produced from GPS-RO measurements. The
limitations of the new ionospheric correction when applied to CHAMP (Challenging Minisatellite Payload)
measurements are noted. These arise because of the assumption that
the refractive index is unity at the satellite, made when deriving
bending angles from the Doppler shift values. |
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