LEEM: A new empirical model of radiation-belt electrons in the low-Earth-orbit region

A new empirical model of radiation-belt electrons in the low-Earth-orbit region has been developed based upon decade-long in situ observations from several low-altitude-orbiting satellites. This model-LEEM-aims to provide the electron environment conditions that a satellite would encounter in a given low Earth orbit. This model presents electron flux values for five energy ranges (0.03-2.5 MeV, 0.1-2.5 MeV, 0.3-2.5 MeV, 1.5-6 MeV, and 2.5-14 MeV) within the space below an altitude of similar to 600 km. Compared to the de-facto standard empirical model of AE-8, this model not only has a better data coverage in this specific region, but also can provide statistical information on flux levels such as worst cases and occurrence percentiles instead of solely mean values. The comparison indicates that the AE-8 model not only highly overpredicts the fluxes in the inner belt region in most cases, especially for the MeV electrons, which cannot be accounted for by the widely quoted error factor of 2 for AE-8, but also is unable to reflect the observed orders of magnitude variations in electron intensities. The LEEM model is carefully validated with both in-sample and out-of-sample tests. The characteristic electron environments along the International Space Station track and other virtual orbits are given as examples and as a demonstration of the use of the model.