Optimum temporal update periods for regional ionosphere monitoring

Monitoring of the ionospheric variability is necessary for improving the performance of communication, navigation, and positioning systems. Total electron content (TEC) is an important parameter in analyzing the variability of the ionosphere. Owing to sparse distribution of TEC in a given region, spatial interpolation methods are used for mapping TEC on a dense grid. Typically, TEC maps are produced at time intervals that do not match the variability of the regional ionosphere. To capture the local, small-scale variability, the temporal update period (TUP) in regional TEC monitoring has to be optimized. In this study, the wide sense stationarity (WSS) period is proposed to be used as the optimum TUP of the regional TEC maps. Individual WSS periods of TEC are obtained by the sliding window statistical analysis method. Four types of measures are employed to compute the differences between TEC maps. When WSS periods of the sampling points and the differences of TEC maps are compared with each other, it is observed that for the quiet days of the ionosphere where the general temporal trends dominate, the maximum WSS period in the region can be chosen as the optimum TUP. For the disturbed days of the ionosphere where high temporal and spatial variability is observed, averages or the minimums of WSS periods in a given region have to be chosen as the optimum TUP. Thus, WSS period can be developed into a useful tool in monitoring the ionospheric variability in a given region.