Ionosphere Monitoring and Prediction Center

One minute mean ROTI, Global

Mean ROTI is presented for the preceding minute on a global map.

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Product Description

The Rate of TEC index (ROTI) is defined as standard deviation of the rate of TEC (ROT) assuming the ionosphere as a thin layer. Hence the index provides information about temporal ionospheric irregularities. DLR’s ROTI is calculated globally. As input GPS dual-frequency data is acquired from different providers, like IGS and EUREF, in real-time via the German Federal Agency for Cartography and Geodesy in Frankfurt. These data is used to calculate relative TEC as input for the ROTI processing. The standard deviation is calculated over a one minute window and the ROT is calculated each second.

The ROTI measurements are mapped into a regular grid (2°x2° lat/lon). Each grid cell presents the mean of the ROTI measurements located in this cell.

Product Specification

SpecificationDescription
External partiesGerman Federal Agency for Cartography and Geodesy
Data providersIGS, EUREF, ASI, Greenland network of the Technical University of Denmark
Input dataGPS dual-frequency measurements
Input sampling rates1s
Reliability of data sourceData is preprocessed by DLR including e.g. cycle slip detection
Region of sensorsEurope
Sensorscf. station list
Single-layer shell height400 km
Spatial resolution2° x 2° latitude-longitude-bins stations
Boundaries of gridglobal
Temporal resolution15 min
Time informationUTC Time
Reference coordinate systemECEF coordinate system with WGS84 reference ellipsoid
AlgorithmsThe rate of TEC (ROT) is calculated receiver-satellite-link specific with a time difference that corresponds to the usual sampling rate of 1 Hz. Based on the ROT the ROTI is calculated over a sliding window of one minute. Afterwards the available ROTI values are binned in 2°x2° bins and averaged. The minimum number of samples within one bin equals one.
File formatASCII
ASCII file formatJSON: this file format includes metadata and data; the meta data key “data” provides a data matrix of ROTI values where the first row represents all ROTI values between 20°W-45°E for a latitude of 25°N

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