TERRAPUB Earth, Planets and Space

Earth Planets Space, Vol. 52 (No. 11), pp. 893-899, 2000

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

K. Igarashi1, A. Pavelyev2, K. Hocke3, D. Pavelyev2, I. A. Kucherjavenkov2, S. Matyugov2, A. Zakharov2, and O. Yakovlev2

1Communications Research Laboratory, Ministry of Posts and Telecommunications, 4-2-1 Nukui-Kita Machi, Koganei-shi, Tokyo 184-0015, Japan
2Institute of Radio Engineering and Electronics of Russian Academy of Sciencies (IRE RAS), Fryazino, Vvedenskogo sq. 1, 141120 Moscow region, Russia
3GeoForschungsZentrum Potsdam (GFZ-Potsdam), Telegrafenberg, 14473 Potsdam, Germany

(Received December 20, 1999; Revised September 25, 2000; Accepted September 26, 2000)

Abstract: 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 l1 compared to l1/2 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.

Corresponding author E-mail: igarashi@crl.go.jp

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