Abstract
Solar Spectrum Prediction for Applications and Modeling (SPAM) – a new
empirical model of solar X-Ray, EUV and FUV radiation flux at the top of
the Earth’s atmosphere. The model is based on 14 years of daily averaged
TIMED spacecraft measurements from 2002 to 2016 when the SEE sensors
were regularly calibrated. We used a second-order parametrization of the
irradiance spectrum by a single parameter – the F10.7 index, which is a
reliable and consistently observed measure of solar activity. The SPAM
model consists of two submodels for general and specific use. The first
is the Solar-SPAM model of the photon energy flux in the first 190 1nm
spectral bands, which can be used for a wide range of applications in
different fields of research. The second model, Aero-SPAM, is designed
specifically for aeronomic research and provides a photon flux for 37
specific wavelength intervals (20 wave bands and 16 separate spectral
lines within the range of 5 –105 nm and an additional 121.5 nm Ly-alpha
line), that play a major role in the photoionization of atmospheric gas
particles. We provide the full set of parameterization coefficients that
allows for immediate implementation of the model for research and
applications. In addition, we used the Aero-SPAM model to build a
ready-to-use numerical application for calculating the photoionization
rates of the main atmospheric components N2, O2, O, N and NO with known
absorption and ionization cross sections.