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Abstract:
FARBES (Forecast of Radiation Belt Scenarios) is a recently started H2020 project to predict the subsequent behavior of a geomagnetic storm after its arrival. For such predictions, FARBES intends to use only ground-based, real-time data to produce input parameters of the radiation belt model, like Salammbô. These input parameters are 1. Outer boundary (magnetopause boundary and injected distribution from the plasmasheet); 2. Background plasma density; 3. Amplitudes of natural waves and their distribution (Chorus, Hiss, EMIC, lightning-whistlers); 4. Amplitude and distribution of radial diffusion coefficients; 5. The low energy boundary condition. Here we focus on the third input data, the ‘Amplitudes of natural waves and their distribution.’ To get the specifications of the in situ natural wave environment, we created an empirical transfer function to describe the attenuation/amplification of whistler-mode waves during their quasi-parallel propagation from the equator through the ionosphere to the ground. We used whistler-mode waves from satellites, like Van Allen Probes, Cluster, and DEMETER, and the ground-based VLF recordings of AWDANet. For this study, we selected the 0.1-0.9 fce (giro-frequency) frequency range of the spectrograms to calculate the average wave powers. Ground-based spectrograms required extensive noise removal (sferics, hum harmonics, etc.) considering the daily attenuation variation of the Earth-Ionosphere waveguide.
