Identification and localization of layers in the ionosphere using the eikonal and amplitude of radio occultation signals

Abstract

Abstract. By using the CHAllenge Minisatellite Payload (CHAMP) radio occultation (RO) data, a description of different types of the ionospheric impacts on the RO signals at the altitudes 30-90 km of the RO ray perigee is given and compared with the results of measurements obtained earlier in the satellite-to-Earth communication link at frequency 1.5415 GHz. An analytical model is introduced for describing propagation of radio waves in a stratified medium consisting of sectors with spherically symmetric refractivity distribution. This model gives analytical expressions for the phase, bending angle, and refractive attenuation of radio waves and is applied to the analysis of radio wave propagation phenomena along an extended path including the atmosphere and two parts of the ionosphere. The model explains significant amplitude and phase variations at altitudes 30-90 km of the RO ray perigee and attributes them to inclined ionospheric layers. Based on this analytical model, an innovative technique is introduced to locate layers in the atmosphere and ionosphere. A necessary and sufficient criterion is obtained for a layer to be located at the RO ray perigee. This criterion gives both qualitative and quantitative estimation of the displacement of an ionospheric and/or atmospheric layer from the RO ray perigee. This is important, in particular, for determining the location of wind shears and directions of the internal wave propagation in the lower ionosphere, and, possibly, in the atmosphere.

Fluctuations of radio occultation signals in sounding the Earth's atmosphere

“…We position the phase screen in the plane crossing the Earth's center and perpendicular to the incident rays. The occultation geometry has been discussed in many papers: Vorob'ev and Krasil'nikova (1994), Ware et al (1996), Gorbunov and Lauritsen (2004), Cornman et al (2004), and Pavelyev et al (2012), as well as further references therein. The phase screen has been discussed in Hubbard et al (1978), Woo et al (1980), Gurvich (1984), and Gurvich and Brekhovskikh (2001).…”

Radio Wave Propagation Phenomena from GPS Occultation Data Analysis

“…The radio occultation (RO) method employs the highly-stable radio waves transmitted at two GPS frequencies 1 f  1575.42 MHz and 2 f  1227.60 MHz by the GPS satellites and recorded at a GPS receiver onboard low Earth orbiting (LEO) satellite to remote sense the Earth's ionosphere and neutral atmosphere [4,5,10,11,17,[23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42]46,47,[52][53][54][55][56][59][60][61]. When applied to ionospheric investigations the RO method may be considered as a global tool and can be compared with the global Earth-and space-based radio tomography [42,43].…”

A comparison of Microtops II and satellite ozone measurements in the period 2001–2011

“…The rest of the measurements were done in rural or marine areas, relatively far away from pollution sources. A detailed description of the sites and observations can be found in Gó mez- Amo et al (2012a) for the campaigns carried out in Madrid and El Arenosillo. The observation station at Valencia is described by Estellé s et al (2007).…”

“…The analyses show that a linear interpolation between the consecutive calibrations produces the best results, also during the years without calibrations, against the Brewers The same calibration strategy was adopted also in this study. In addition, the Microtops procedure to improve the data quality suggested by Gó mez-Amo et al (2012a) was also implemented, and only the series of three or five observations within 1 min which display standard deviation of the signals less than 2% and standard deviation of the AOD at 1020 nm less than 0.015 have been used (Gó mez-Amo et al, 2012a).…”

“…Previous studies were devoted to describe the Microtops and test its performance (Morys et al, 2001), analyzing its advantages, limitations and uncertainties Labow et al, 1996;Köhler, 1999;Holdren et al, 2001) as well as the operational procedures to improve the data quality and its long term performance (Gó mez-Amo et al, 2012a).…”