Sezen, U.Arikan, F.Arıkan, OrhanUgurlu, O.Sadeghimorad, A.2016-02-082016-02-0820131542-7390http://hdl.handle.net/11693/20895The variability of space weather can best be captured using total electron content (TEC), which corresponds to total number of electrons on a ray path. The dual-frequency ground based GPS receivers provide a cost-effective means for monitoring TEC. Computation of TEC for a single GPS station is a challenge due to various unknowns and ambiguities such as inter-frequency receiver bias and satellite bias, choice of mapping function, and peak height of ionosphere for ionospheric piercing point. In this study, IONOLAB group introduces a robust, automatic, online computation routine near-real time TEC, IONOLAB-TEC, for IGS and/or EUREF stations from www.ionolab.org. The user can choose online one station or multiple stations, date or dates for the computation. The IONOLAB-TEC values can be compared with TEC estimates from IGS analysis centers. The output can be obtained either in graphical form, or IONOLAB-TEC estimates can be provided in an excel file. The service is easy to use with a graphical user interface. This unique and original space weather application is provided online, and IONOLAB-TEC estimates are downloaded automatically to the user defined directories under user defined filenames. Key PointsOnline, automatic, near real-time GPS-TEC is estimated as IONOLAB-TECIONOLAB-TEC is available from www.ionolab.org for single/multiple stations/daysIONOLAB-TEC is available in graphics and as excel file ©2013. American Geophysical Union. All Rights Reserved.EnglishGPS-TECIonosphereTotal electron contentArticle10.1002/swe.20054