The department “Space Weather Observations” investigates and applies ionosphere measurement and inversion techniques using ground and space borne sensors. The observational data are used to reconstruct the temporally varying 3D electron density distribution of the geo-plasma environment by means of data fusion, reconstruction and assimilation techniques. The department includes currently three main working areas: space based observations, ground based observations, and data fusion and reconstruction.
Space Based Observations
The focus is on developing powerful space-based methods like the radio occultation (RO) technique for exploring Earth’s upper atmosphere and ionosphere. Research is used to perform continuous monitoring of the Earth’s ionosphere and plasmasphere by tracking GNSS RO and navigation signals from low Earth orbiting (LEO) satellites. Other space-based techniques include ionosphere estimation using dual-frequency altimeter data (e.g. TOPEX-Poseidon, Jason 2 & 3 missions), using radio beacon measurements from DORIS (geodetic orbit determination and positioning system) receivers onboard LEO satellites and GNSS reflectometry. Research performs on development and improvement of current in-situ measurement techniques of electron density (e.g. Langmuir probe), temperature, wind, and composition of the thermosphere (e.g. TIMED, ICON, GOLD missions) and solar irradiance, wind parameters (e.g. ACE/DSCOVR, SDO missions). The tasks include developing powerful processing systems for handling big data sets of space based measurements in near real-time.
Ground Based Observations
The focus is on development of improved measurement and inversion techniques and powerful processing systems for handling big data sets of ground based measurements in near real-time. Ongoing research is necessary for development and enhancement of technology and methodology for continuous monitoring of Earth’s ionosphere using worldwide distributed GNSS sensor stations taking advantage of the multi-constellation, multi-frequency observations and new signals. Other ground based techniques include ionosphere estimation using vertical sounding (VS) and Incoherent Scatter Radar (ISR) data, solar flare monitoring and detection using DLR’s operational Global Ionosphere Flare Detection System (GIFDS). Research includes investigation of EISCAT radar data which can improve understanding of space weather effects on technological systems like GNSS, regional tomography of ionosphere and detection of travelling ionospheric disturbances using radio beacon measurements received on ground.
Data Fusion and Reconstruction
The focus of this working group is to generate 3D electron density reconstructions of the geo-plasma environment up to the plasmapause with high spatial and temporal resolution. The data originating from different sources need to be harmonized and integrated properly to obtain accurate and consistent data sets for direct use in scientific studies. For this, special fusion techniques need to be developed both for post-processing as well as for near real-time solutions. Data fusion to create synthetic data sets requires specific modelling efforts or machine learning procedures. Data gaps in spatially distributed data sets can be filled by empirical modelling information. Hence, synthetic data sets like vertical total electron content (TEC) maps and spatial electron density distributions can be reconstructed by using robust but sufficiently accurate background models. Consequently, the development of fast and robust empirical 2D- and 3D- background models with an excellent performance is one of the key tasks in this working group.
Department for Space Weather Observation
Institute for Solar-Terrestrial Physics