Articles | Volume 35, issue 3
https://doi.org/10.5194/angeo-35-393-2017
https://doi.org/10.5194/angeo-35-393-2017
Regular paper
 | 
14 Mar 2017
Regular paper |  | 14 Mar 2017

High-resolution coherent backscatter interferometric radar images of equatorial spread F using Capon's method

Fabiano S. Rodrigues, Eurico R. de Paula, and Gebreab K. Zewdie

Abstract. We present results of Capon's method for estimation of in-beam images of ionospheric scattering structures observed by a small, low-power coherent backscatter interferometer. The radar interferometer operated in the equatorial site of São Luís, Brazil (2.59° S, 44.21° W, −2.35° dip latitude). We show numerical simulations that evaluate the performance of the Capon method for typical F region measurement conditions. Numerical simulations show that, despite the short baselines of the São Luís radar, the Capon technique is capable of distinguishing localized features with kilometric scale sizes (in the zonal direction) at F region heights. Following the simulations, we applied the Capon algorithm to actual measurements made by the São Luís interferometer during a typical equatorial spread F (ESF) event. As indicated by the simulations, the Capon method produced images that were better resolved than those produced by the Fourier method. The Capon images show narrow (a few kilometers wide) scattering channels associated with ESF plumes and scattering regions spaced by only a few tens of kilometers in the zonal direction. The images are also capable of resolving bifurcations and the C shape of scattering structures.

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Short summary
We present results of Capon's method for the estimation of in-beam images of equatorial spread F (ESF) irregularities observed by the São Luís radar interferometer. Results of numerical simulations show that, despite the short baselines of the system, the method is capable of distinguishing localized features with kilometric scale sizes (zonal direction). Results from the application of Capon’s method to actual measurements show that it is able to resolve features expected to occur in ESF.