Assessment of La Plata Ionospheric Model using synthetic data based on NeQuick Ionospheric Model

AZPILICUETA, F.; BRUNINI, C.; RADICELLA, S.; CIRAOLO, L.

Trieste, Italia.

Simposio; International Beacon Satellite Symposium; 2004

International Center for Theoretical Physics

A widely used approach for global vertical TEC (vTEC) modeling based on GPS data uses spherical harmonics series expansions to represent the geographical distribution of vTEC. As in any technique of this type, a set of simplified hypothesis are assumed, among them: single layer representation of the ionosphere with constant height, geometrical conversion factor from slant to vertical TEC values, adoption of appropriate spatial and temporal coordinates, and statistical constrains on the coefficients of the series expansion. In addition to these assumptions another important issue is the goodness of the representation of the global vTEC distribution that could be expected from a spherical harmonic series expansion of certain order and degree.On the present work, an optimum scenario has been adopted by simulating a globally homogenously distributed grid of vTEC values using the NeQuick model. This simulation allows analyzing the limits of the spherical harmonics representation, independently of the problems that may arise from the uneven distribution of real observational sites, slant to vertical TEC conversion errors, etc.It is shown that such representations deviate from the simulated ionosphere in the region of low latitudes.