Assimilation procedures for updating ionospheric profiles below the F2 peak

摘要: [1] This paper describes and compares two real-time assimilative ionospheric models, with an emphasis on their ability to provide accurate profiles of the electron density below peak F2 layer at a midlatitude location, given automatically processed vertical incidence ionograms single location. The models are specifically oriented toward several important practical applications high-frequency (HF) radio propagation: HF communications, station location transmitters, coordinate registration for OTHR. Both start International Reference Ionosphere (IRI) as background ionosphere assimilate digisonde observations (either ionogram or profile) available GPS total content observations. data from one site in Republic South Africa (RSA) ionosonde assimilation data, while other three digisondes RSA ground-truth foF2, hmF2, plasma frequency profile. Since four receive each other's transmissions, maximum observed frequencies have also been used ground truth. tested both found significant improvements over IRI similar accuracies study interval (September 2011). errors very close minimum achievable all validation parameters, which seem be set by ubiquitous traveling disturbances being different locations. For optimum ~685 km providing RMS foF2 were 0.2 MHz (night) 0.5 MHz (day).