Processing and validation of refractivity from GRAS radio occultation data

Backpropagation Processing of GPS Radio Occultation Data

We provide an assessment of the backpropagation (BP) method for processing GPS radio occultations using simulations as well as recent data from CHAMP and SAC-C. It is found that BP gives improved retrievals over the standard Doppler technique, even when multipath ambiguities are not completely removed. In addition, by being an amplitude-weighted algorithm, BP is robust in the presence of receiv...

Vertical Gradients of Refractivity in the Mesosphere and Atmosphere Retrieved from GPS/MET and CHAMP Radio Occultation Data

Fine structures in the vertical gradient of the electron density have been retrieved by means of analysis of the amplitude of radio occultation (RO) data in sporadic E-layers (heights interval 85-110 km). Maximum values of the positive gradients 45⋅10, 48⋅10, 25⋅10, 29⋅10 [mkm] are located at levels 92, 105 km (GPS/MET event 0393) and 93.5, 100 km (GPS/MET event 0583). Variations in the vertica...

Assimilation of GPS Radio Occultation Refractivity Data from CHAMP and SAC-C Missions over High Southern Latitudes with MM5 4DVAR

In this study, the GPS radio occultation (RO) data from the Challenging Minisatellite Payload (CHAMP) and Satellite de Aplicaciones Cientificas-C (SAC-C) missions are assimilated. An updated version of the fifth-generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model (MM5) four-dimensional variational data assimilation system (4DVAR) is used to assess t...

Evaluation of a non-local observation operator in assimilation of CHAMP radio occultation refractivity with WRF

Estimation of Radio Refractivity Structure Using Matched-Field Array Processing

In coastal regions the presence of the marine boundary layer can significantly affect RF propagation. The relatively high specific humidity of the underlying “marine layer” creates elevated trapping layers in the radio refractivity structure. While direct sensing techniques provide good data, they are limited in their temporal and spatial scope. There is a need for assessing the three-dimension...