ROTI Maps: a new IGS ionospheric product characterizing the ionospheric irregularities occurrence

The International GNSS Service (IGS) has recently accepted for official release a new ionospheric product to characterize ionospheric irregularity and intensity as derived from multi-site ground-based GPS observations. This product was developed and implemented in the Space Radio-Diagnostic Research Center (SRRC), University of Warmia and Mazury. The SRRC has implemented this approach using in-house software for multi-step processing and interpretation of carrier phase delays in dual-frequency GPS signals and provides the new product to the IGS database. We used measurements with 30-s sampling rate from about 700 GPS stations located at high and middle latitudes of the Northern Hemisphere. The product represents changes in the GPS-based Rate of TEC Index (ROTI) and has a polar projection within a range of 50\textdegree\textendash90\textdegreeN in geomagnetic latitude and 00\textendash24 magnetic local time. The new service allows regular monitoring of ionospheric irregularities over the Northern Hemisphere. We demonstrate results of visualization and analysis of the IGS ROTI Maps product for representative periods with geomagnetically quiet conditions and severe geomagnetic storms in 2014\textendash2015 in order to demonstrate the performance and ability of this product to depict the development of ionospheric irregularities in the area of interest. During space weather events, the ionospheric irregularities oval, as deduced from the ROTI Maps, expands significantly in size toward midlatitudes with simultaneous increase in irregularities intensity, which can lead to degradation of the GPS precise positioning performance at lower latitudes.