A correction factor of bottomside thickness parameter for computing TEC in global navigation satellite systems

This paper proposes two new equations for computing the bottomside thickness parameter of the NeQuick 2 model with a correction factor (B2bot Pro2) and the simulated TEC values (TEC Pro). The main contributions of this work are twofold, i.e., 1) the proposed B2bot Pro2 equation can be used to compute the bottomside thickness whose trends and values are close to ones of the observed B0 (B0 obs) obtains from DPS-4 (Digisonde) and 2) the computed B2bot Pro2 are used to compute the TEC values without additional TEC observation by any devices and TEC computation. In this case, it is useful for some locations where there exist only ground-based ionosonde without TEC observation or TEC measurement doesn't work in some situations. The results show that the B2bot Pro2 have the same trends as the B0 obs. They are closer to the B0 obs, except at 13LT in June solstice and September equinox. The averages of absolute differences between B2bot Pro2 and B0 obs (avAD Pro2) are generally lower than about 8 km. They show that the B2bot Pro2 are close to the B0 obs with the improved percentages of higher than 80%. The TEC computed using the B2bot Pro2 equation (TEC Pro) in the nighttime are generally close to the observed TEC (TEC obs) compared with those in the daytime.