Ionosphere Monitoring and Prediction Center

One hour Forecast TEC Map, Global

DLR’s 1 hour forecast global TEC maps provide information about the vertical TEC (VTEC) one hour ahead with a latency of not more than 5 minutes and an update rate of 15 minutes. The maps have a global coverage with 2.5° in latitudes and 5° in longitude spatial resolution. The one hour forecast is calculated as a sum of the actual global TEC map and a weighted sum of the temporal TEC gradient of the previous hour and the temporal gradient of the previous day at the same time.

Latest Data

Product Description

The 1 hour forecast TEC is provided in TEC units (1016 electrons per square meter) for a shell-height of 400 km.

Every 5 minutes a VTEC matrix with an ionospheric grid point spacing of 2.5° latitude x 5° longitude is generated and stored in ASCII format. Data is provided here with 15 minutes updated rate. Higher temporal resolution can be provided on request.

This product can be applied to help to improve the accuracy during GNSS positioning. Related validations can be found for instance in Minkwitz et al. (2014). The quality of the 24 hours forecast TEC map is estimated with the deviation between forecast and observation. These errors are monitored through the production pipeline and displayed in a forecast TEC error map. This forecast TEC error map is provided as quality information along with the product.

SpecificationDescription
External partiesGerman Federal Agency for Cartography and Geodesy, data providers below
Data providersIGS, Greenland network of the Technical University of Denmark
Input data GPS dual-frequency measurements
Input sampling rates 1 s
Reliability of data source Data is preprocessed by DLR including e.g. cycle slip detection
Region of sensors Global
Sensorscf. station list
Single layer shell height400 km
Spatial Resolution2.5° Latitude x 5° Longitude
Boundaries of grid-90°N – 90°N, 180°W – 180°E
Temporal Resolution15 min
Time InformationUTC Time
Reference coordinate SystemECEF coordinate system with WGS84 reference ellipsoid
AlgorithmsThe one hour forecast is calculated as a sum of the actual European TEC map and a weighted sum of the temporal TEC gradient of the previous hour and the temporal gradient of the previous day at the same time.
File formatASCII
ASCII file format 

Header line containing: unit of TEC values, UTC time, minimum latitude in degree, maximum latitude in degree, minimum longitude in degree, maximum longitude in degree, latitude step width in degree, longitude step width in degree, size of data matrix

Data matrix with VTEC values in TECU (1e+16 electrons/m²): Upper left corner value represents the minimum longitude and maximum latitude; the lower right corner value represents the maximum longitude and minimum latitude value

Quality Information

Error of the NRT TEC map, global, derived from errors of the GNSS measurements.

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