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Atmospheric Physics and Radiopropagation Laboratory, International Centre tor Theoretical Physics, Trieste, Italy
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- PublicationOpen AccessAn improved bottomside for the ionospheric electron density model NeQuick(2005)
; ; ; ;Leitinger, R.; Institut für Physik, Institutsbereich für Geophysik, Astrophysik und Meteorologie (IGAM), Universität Graz, Austria ;Zhang, M. L.; Laboratory for Space Weather, Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing, People s Republic of China ;Radicella, S. M.; The Abdus Salam International Centre for Theoretical Physics (ICTP), Trieste, Italy; ; The ionospheric electron density model NeQuick is a «profiler» which uses the peaks of the E-layer, the F1-layer and the F2-layer as anchor points. In the version prepared for and submitted to the International Telecommunication Union (ITU) the model uses the ITU-R (CCIR) maps for foF2 and M(3000)F2 and adapted maps similar to the ITU-R ones for foE and foF1. Since users found problematic behaviour of NeQuick under conditions of strong differences of foE and foF2 map structures, the profiling was adapted by changing the properties of the Epstein layers used for this purpose. The new formulation avoids both strange horizontal structures of the geographic distribution of electron density in fixed heights and unrealistic peculiarities of the height profile which occasionally occurred with the old version of the model. Since the Epstein layer approach allows for 8 parameters only (3 layer amplitudes and 5 semi-thicknesses) the adaptation was no minor task but needed careful planning of suitable strategies.426 4131 - PublicationOpen AccessThe improved DGR analytical model of electron density height profile and total electron content in the ionosphere(1995-03)
; ; ;Radicella, S. M.; Atmospheric Physics and Radiopropagation Laboratory, International Centre tor Theoretical Physics, Trieste, Italy ;Zhang, M. L.; Atmospheric Physics and Radiopropagation Laboratory, International Centre tor Theoretical Physics, Trieste, Italy; Tests of the analytical model of the electron density profile originally proposed by G, Di Giovanni and S.M. Radicella (DGR model) have shown the need to introduce improvements in order to obtain a model able to reproduce the ionosphere in a larger spectrum of geophysical and time conditions. The present paper reviews the steps toward such progress and presents the final formulation of the model. It gives also a brief re- view of tests of the improved model done by different authors.657 840 - PublicationOpen AccessIonogram inversion F1-layer treatment effect in raytracing(2005)
; ; ; ;Miró Amarante, G.; The Abdus Salam International Centre for Theoretical Physics (ICTP), Trieste, Italy ;Zhang, M. L.; Laboratory for Space Weather, Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing, People s Republic of China ;Radicella, S. M.; The Abdus Salam International Centre for Theoretical Physics (ICTP), Trieste, Italy; ; This paper shows the importance of the F1-layer shape in the electron density profiles obtained from ionograms with different inversion techniques when the profiles are used in ray tracing. This layer often controls the propagation on the path with ranges less than about 2000 km, particularly for spring and summer periods. Ionograms from two different stations, Hainan (19.4N, 109E) and El Arenosillo (37.1N, -6.7E), obtained during the month of July 2002 (average sunspot number: 99.6) during geomagnetic quiet conditions (Ap-index between 9 and 15) are analyzed. The profiles obtained with two different inversion techniques with different options are used together with the ray tracing program of the Proplab-Pro software. This program calculates the features of the received signal as angle of arrival, path length, height of reflection and range for each given profile assumed to define a spherically symmetric ionosphere in the region along the path. For each ionospheric condition (location, day, hour) the difference between range values obtained with Proplab-Pro program using profiles from the two techniques and the different options (POLAN no valley, POLAN valley, POLAN1-layer and NHPC) are considered.168 356