Direct Data Assimilation Over Solar Cycle Time-Scales to Improve Proton Radiation Belt Models

Data assimilation technique has already been developed and proved its worth to provide dasiathe bestpsila estimate of the current state of the electron radiation belts. Data assimilation proceeds by analysis cycles. In each analysis cycle, observations of the current (and possibly, past) state of a system are combined with the results from a mathematical model (the forecast) to produce an analysis, which is considered as dasiathe bestpsila estimate of the current state of the system. Here we present its adaptation to the case of proton radiation belts over solar cycle time-scales. Many deficiencies of AP8 models can be overcome thanks to direct data assimilation. An anticorrelation between the <10 MeV proton radiation belts and solar activity is put forward. However, the definition of only an average state for solar minimum and solar maximum seems to be insufficient to respond to the need of precision required by the reanalysis of > 10 MeV proton radiation belts. Point-like but intense events can have long term effects which depend on whether a SPE (solar proton event) is associated or not with this storm period.