Journal cover Journal topic
Atmospheric Measurement Techniques An interactive open-access journal of the European Geosciences Union

Journal metrics

  • IF value: 2.989 IF 2.989
  • IF 5-year<br/> value: 3.489 IF 5-year
    3.489
  • CiteScore<br/> value: 3.37 CiteScore
    3.37
  • SNIP value: 1.273 SNIP 1.273
  • SJR value: 2.026 SJR 2.026
  • IPP value: 3.082 IPP 3.082
  • h5-index value: 45 h5-index 45
Atmos. Meas. Tech., 8, 3385-3393, 2015
http://www.atmos-meas-tech.net/8/3385/2015/
doi:10.5194/amt-8-3385-2015
© Author(s) 2015. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
21 Aug 2015
A modification to the standard ionospheric correction method used in GPS radio occultation
S. B. Healy1 and I. D. Culverwell2 1European Centre for Medium-range Weather Forecasts (ECMWF), Reading, UK
2Met Office, Exeter, UK
Abstract. 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.

Citation: Healy, S. B. and Culverwell, I. D.: A modification to the standard ionospheric correction method used in GPS radio occultation, Atmos. Meas. Tech., 8, 3385-3393, doi:10.5194/amt-8-3385-2015, 2015.
Publications Copernicus
Short summary
This paper presents a new method for reducing the impact of residual ionospheric errors in geophysical climatologies derived from GPS radio occultation measurements.
This paper presents a new method for reducing the impact of residual ionospheric errors in...
Share