Radio occultation data analysis by the radioholographic method

The radioholographic method is briefly described and tested by using data o f 4 radio occultation events observed by the GPS/MET experiment on 9 Februa ry 1997, The central point of the radioholographic method (Pavelyev, 1998) is the generation of a radiohologram along the LEO satellite trajectory whi ch allows the calculation of angular spectra of the received GPS radio wave field at the LEO satellite. These spectra are promising in view of detecti on, analysis and reduction of multipath/diffraction effects, study of atmos pheric irregularities and estimation of bending angle error. Initial analys is of angular spectra calculated by the multiple signal classification (MUS IC) method gives evidence that considerable multibeam propagation occurs at ray perigee heights below 20 km and at heights around 80-120 km for the 4 GPS/MET occultation events. Temperature profiles obtained by our analysis ( radioholographic method, Abel inversion) are compared with those of the tra ditional retrieval by the UCAR GPS/MET team (bending angle from slope of ph ase front, Abel inversion). In 3 of 4 cases we found good agreement (standa rd deviation sigma(T) similar to 1.5 degrees K between both retrievals at h eights 0-30 km). (C) 1999 Elsevier Science Ltd. All rights reserved.