Comparative analysis of radioholographic methods of processing radio occultation data

Горбунов, М. Е.; Gurvich, A. S.; Kornblueh, Luis

doi:10.1029/1999rs002247

Cited by 53 publications

(54 citation statements)

References 17 publications

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“…Refractivity pro files are re trieved from GPS RO sig nals re ceived by the COS MIC sat el lites us ing the pro cess ing pro ce dures ex plained in de tail by Kuo et al (2004). The CDAAC data pro cess ing soft ware in cludes four radioholographic al go rithms, that is, back prop a ga tion met hod (Gorbunov et al 2000), slid ing spec tral method (Sokolovskiy 2001a), ca non i cal trans form method (Gorbunov 2002), and full spec trum in ver sion (FSI) method (Jensen et al 2003) in or der to in vert RO sig nals which passed through the moist tro po sphere where the multipath prop a ga tion is com mon and the con ven tional (geo met ric op tics) method does not work. The COS MIC refractivity pro files in the lower tro po sphere are de rived by the FSI method since it is op ti mal as to ac cu racy and com pu ta tional cost.…”

Section: Data and Methods Of Com Par I Sonsmentioning

confidence: 99%

Validation of Refractivity Profiles Retrieved from FORMOSAT-3/COSMIC Radio Occultation Soundings: Preliminary Results of Statistical Comparisons Utilizing Balloon-Borne Observations

Hayashi¹,

Furumoto²,

Lin³

et al. 2009

Terr. Atmos. Ocean. Sci.

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AB STRACTThe GPS ra dio occultation (RO) soundings by the FORMOSAT-3/COS MIC (Tai wan's Formosa Sat el lite Misssion #3/Con stel la tion Ob serv ing Sys tem for Me te o rol ogy, Ion o sphere and Cli mate) sat el lites launched in mid-April 2006 are com pared with high-res o lu tion bal loon-borne (ra dio sonde and ozonesonde) ob ser va tions. This pa per pres ents pre lim i nary re sults of val i da tion of the COS MIC RO mea sure ments in terms of refractivity through the tro po sphere and lower strato sphere. With the use of COS MIC RO soundings within 2 hours and 300 km of sonde pro files, sta tis ti cal com par i sons be tween the col lo cated refractivity pro files are per formed for some trop i cal re gions (Ma lay sia and West ern Pa cific is lands) where mois ture-rich air is ex pected in the lower tro po sphere and for both north ern and south ern po lar ar eas with a very dry tro po sphere. The re sults of the com par i sons show good agree ment be tween COS MIC RO and sonde refractivity pro files through out the tro po sphere (1 -1.5% dif fer ence at most) with a pos i tive bias gen er ally be com ing larger at pro gres sively higher al ti tudes in the lower strato sphere (1 -2% dif fer ence around 25 km), and a very small stan dard de vi a tion (about 0.5% or less) for a few ki lo me ters be low the tropo pause level. A large stan dard de vi a tion of frac tional dif fer ences in the low er most tro po sphere, which reaches up to as much as 3.5 -5% at 3 km, is seen in the tropics while a much smaller standard deviation (1 -2% at most) is evident throughout the polar troposphere.

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Section: Data and Methods Of Com Par I Sonsmentioning

confidence: 99%

Validation of Refractivity Profiles Retrieved from FORMOSAT-3/COSMIC Radio Occultation Soundings: Preliminary Results of Statistical Comparisons Utilizing Balloon-Borne Observations

Hayashi¹,

Furumoto²,

Lin³

et al. 2009

Terr. Atmos. Ocean. Sci.

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“…Moreover, because BP does not take into account of the atmosphere, rays that diverge at the LEO could very well converge at the BP orbit if we were to position it too far back. To avoid intersection with these so-called imaginary caustics, Gorbunov et al [9] suggested a simple rule of thumb for the limb distance of the BP plane as x BP = R E α max , where R E is the radius of curvature of the Earth and α max is the maximum bending angle. For typical occultation parameters, x BP = 200 km.…”

Section: Formulationmentioning

confidence: 99%

“…In recent years, a number of "radioholographic" methods have been proposed that not only aimed to resolve the multipath problem encountered by the standard method but also to improve the vertical resolution of the retrievals [7,8,9,10,11,12]. These methods use both the amplitude and phase of the received signal in reconstructing the ray structure of the refracted field.…”

Section: Introductionmentioning

confidence: 99%

Backpropagation Processing of GPS Radio Occultation Data

Hajj

Meehan

et al. 2003

First CHAMP Mission Results for Gravity, Magnetic and Atmospheric Studies

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Summary.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 receiver errors that arise when signals with low SNR are tracked.

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“…Using knowledge on the expected atmosphere conditions (included in the phase function ψ m (t)) for optimal measuring angular position of the ray's in angular spectrum is a main point of the radio holographic method. This is a main distinction from quantum cell approach now under elaboration by Gorbunov et al (2000). Spectral radio holographic method reveals only the rays in the angular spectrum that are in coherence (or matched in the sense of high resolution radar imaging technology) with the reference beam.…”

Section: Radio Holographic Methodsmentioning

confidence: 99%

Radio holographic principle for observing natural processes in the atmosphere and retrieving meteorological parameters from radio occultation data

et al. 2014

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The radio holographic principle is briefly described and tested by using radio occultation data of the GPS/MET and MIR/GEO experiments. Sub-Fresnel spatial resolution ∼12 m/pixel was achieved using focused synthetic aperture radio holographic approach, and direct evidence of multibeam propagation effects in the atmosphere was obtained. The achieved instrumental accuracy in angular distance measurements was near 0.004 milliradian/pixel, and observed angular distance between different rays was equal to 0.3 milliradians. The angular resolution of the radio holographic method depends on the wavelength as λ 1 compared to λ 1/2 in conventional methods. In general case the principal limit of the vertical resolution may be determined using focused synthetic aperture antenna theory and may achieve a value ∼20-40 m under assumptions of spherical symmetry and quiet atmospheric conditions. Wave structures were discovered in the altitude distribution of the gradient electron density at a height interval of 60-95 km with spatial period 1-2 km and vertical resolution 300-500 m. Good correspondence was found between the temperature profiles revealed by radio holographic analysis and those obtained by traditional retrieval using UCAR GPS/MET data.

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Comparative analysis of radioholographic methods of processing radio occultation data

Abstract: Abstract.Two methods for the determination of refraction angle profiles from radio occultation measurements in nmltipath areas are analyzed and compared: (1) the radio-

Cited by 53 publications

References 17 publications

Validation of Refractivity Profiles Retrieved from FORMOSAT-3/COSMIC Radio Occultation Soundings: Preliminary Results of Statistical Comparisons Utilizing Balloon-Borne Observations

Validation of Refractivity Profiles Retrieved from FORMOSAT-3/COSMIC Radio Occultation Soundings: Preliminary Results of Statistical Comparisons Utilizing Balloon-Borne Observations

Backpropagation Processing of GPS Radio Occultation Data

Radio holographic principle for observing natural processes in the atmosphere and retrieving meteorological parameters from radio occultation data

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