Due to network problems, the ISM nowcast and forecast services are temporary interrupted.
Our teams are working to solve this problem. Sorry for the inconvenience.
The application is retrieving data
Ionosphere is the region of atmosphere between altitudes 100 km and 1500 km above sea level. It is characterized by its electron density which peaks around the magnetic equator and decreases as the latitude increases. The low latitudes region is in addition a region where strong inhomogeneities inside the medium may occur. These inhomogeneities are sub structures of bubbles, which may reach dimensions of several hundreds of kilometers as can be seen from radar observations. These bubbles present a patchy structure. They appear after sunset, when the sun ionization drops to zero. Instability processes develop inside these bubbles with creation of turbulences inside the medium. As a result, depletions of electron density appear.
As a result of propagation through these ionosphere electron density irregularities, transionospheric radio signals may experience amplitude and phase fluctuations. In equatorial regions, these signal fluctuations specially occur during equinoxes, after sunset, and last for a few hours. They are more intense in periods of high solar activity. There is also a longitudinal dependency. These fluctuations result in signal degradation from VHF up to C band. They are a major issue for many systems including Global Navigation Satellite Systems (GNSS), telecommunications, remote sensing and earth observation systems.
On the nowcast part of the service, 3 types of maps are available:
At the bottom of the page, it is possible to get the numerical values of the scintillation or TEC at a given location by entering its coordinates.
Each map is also associated with a confidence level map, as for the nowcast maps.
The remaining observations used in the service come from geodetic receivers from three permanent GNSS networks : IGS, CORS and SOPAC. The IGS network offers data either at a 1s or 30s observation rate, whereas the 2 other networks only have 30s observation rate data. Stations were selected by combining the 3 networks, to obtain a maximum coverage, keeping a minimum distance of 200 km between stations.
The chosen deterministic model is GISM (developed by IEEA). For this model, the indices depend on the date, the location and the solar flux (daily F10.7).
The correlation function of the random variable is considered to decrease exponentially regarding the distance between two measured points.
This web page forms part of the ESA Space Situational Awareness Programme's network of space weather service development activities, and is supported under ESA contract number 4000107200/12/D/MRP.
Please note that all SSA-SWE service developments are under review and testing and should not at this stage be used for operational purposes. For further product-related information or enquiries contact helpdesk. E-mail: firstname.lastname@example.org
All publications and presentations using data obtained from this site should acknowledge CLS, IEEA and ESA/SSA-SWE.
For further information about space weather in the ESA Space Situational Awareness Programme see: www.esa.int/spaceweather
Access the SSA-SWE portal here: swe.ssa.esa.int
IEEA has developed an ionosphere mapping technique based on a Krigging algorithm. The algorithm takes as an input the data recorded by ground based receivers. These data are assimilated in a regression model (GISM) validated against measurements on the occasion of several measurement campaigns.
CLS was in charge of the processing chain that converts raw observations from GNSS stations into calibrated data values at IPPs (ionospheric pierce points). It consisted in selecting a worldwide set of stations based on existing networks, developing algorithms to compute scintillation and TEC values as well as IPP locations, and correlating data from geodetic and specific ionospheric receivers.
SWE Portal [2.5.0], Copyright 2000 - 2017 © European Space Agency. All rights reserved.