TEC data assimilation into NeQuick2

NAVA BRUNO; ALZAZO K.; KASHCHEYEV ANTON; AZPILICUETA FRANCISCO

Pasadena

Workshop; 42nt COSPAR Assembly; 2018

COSPAR

NeQuick 2 is the ionosphere electron density model developed at the Abdus Salam International Centre for Theoretical Physics (ICTP) ‐ Trieste, Italy in collaboration with the University of Graz, Austria.To provide 3-D specifications of the ionosphere electron density for current conditions, different ionosphere electron density retrieval techniques based on the NeQuick adaptation to Total Electron Content (TEC) data and ionosonde measured peak parameters values have been proposed. Recently, a procedure based on the Best Linear Unbiased Estimator (BLUE) has been implemented to incorporate ground and space-based GNSS-derived TEC data into NeQuick, considered as a background model. In the present paper an overview of the mentioned assimilation techniques will be given and the latest development concerning the assimilation of Radio Occultation (RO)-derived TEC data into NeQuick will be presented.As a first step, the results of a simulation experiment will be described to evaluate the relevance of the RO-derived TEC data assimilation in the topside electron density reconstruction. More specifically, it will be shown that the inclusion of RO TEC data can improve the description of the topside profile shape (scale height), but not always allows for a sufficiently accurate reconstruction of the peak density and height. Indeed, it will also be demonstrated how the background model slab thickness can play an important role in the analysis results.Subsequently, using experimental data, specific test cases will be illustrated where the BLUE algorithm is used to assimilate both ground a space-based TEC data. In particular, the effects of assimilating RO TEC data on the reconstruction of the ionospheric electron density at selected locations and epochs will be discussed and interpreted in light of the simulation outcomes. For this purpose, independent ground truth measurements like manually scaled F2 layer peak parameter values will be utilised to evaluate the performance of the proposed assimilation procedure.