Statistical analysis of regional STEC gradient trends for midlatitude ionosphere  

作　　者：Meltem Koroglu Feza Arikan 

机构地区：[1]Department of Telecommunication Design,Plan-S Satellite and Space Technologies Inc,Bilkent,Ankara,600,Turkey [2]Department ofElectrical and Electronics Engineering,Hacettepe University,Beytepe,Ankara,60,Turkey

出　　处：《Geodesy and Geodynamics》2025年第1期7-28,共22页大地测量与地球动力学(英文版)

基　　金：supported by TUBITAK 112E568,114E092,and 115E915 projects;TNPGN-Active RINEX data set is available to the IONOLAB group for the TUBITAK 109E055 project。

摘　　要：In this study,the gradients of Total Electron Content(TEC)for a midlatitude region are estimated and grouped with respect to the distance between neighboring stations,time periods within a day,and satellite directions.Annual medians of these gradients for quiet days are computed as templates.The metric distances(L2N)and Symmetric Kullback-Leibler Distances(SKLD)are obtained between the templates and the daily gradient series.The grouped histograms are fitted to the prospective Probability Density Functions(PDF).The method is applied to the Slant Total Electron Content(STEC)estimates from the Turkish National Permanent GPS Network(TNPGN-Active)for 2015.The highest gradients are observed in the east-west axis with a maximum of 25 mm/km during a geomagnetic storm.The maximum differences from the gradient templates occur for neighboring stations within100-130 km distance away from each other,during night hours,and for regions bordering the Black Sea and the Mediterranean in the northeast and southeast of Turkey.The empirical PDFs of the stationpair gradients are predominantly Weibull-distributed.The mean values of Weibull PDFs in all station groups are between 1.2 and 1.8 mm/km,with an increase during noon and afternoon hours.The standard deviations of the gradient PDFs generally increase during night hours.The algorithm will form a basis for quantifying the stochastic variations of the spatial rate of change of TEC trends in midlatitude regions,thus supplementing reliable and accurate regional monitoring of ionospheric variability.

关 键 词：onospheric disturbances lonospheric gradient Statistical modeling Ground based augmentation system 

分 类 号：P228.4[天文地球—大地测量学与测量工程]