Comparison of ionospheric radio occultation CHAMP data with IRI 2001

GPS radio occultation measurements on board low Earth orbiting satellites can provide vertical electron density profiles of the ionosphere from satellite orbit heights down to the bottomside. Ionospheric radio occultation (IRO) measurements carried out onboard the German CHAMP satellite mission since 11 April 2001 were used to derive vertical electron density profiles (EDP’s) on a routine basis. About 150 vertical electron density profiles may be retrieved per day thus providing a huge data basis for testing and developing ionospheric models. Although the validation of the EDP retrievals is not yet completed, the paper addresses a systematic comparison of about 78 000 electron density profiles derived from CHAMP IRO data with the International Reference Ionosphere (IRI 2001).</p><p style=&quot;line-height: 20px;&quot;> The results are discussed for quite different geophysical conditions, e.g. as a function of latitude, local time and geomagnetic activity.</p><p style=&quot;line-height: 20px;&quot;> The comparison of IRO data with corresponding IRI data indicates that IRI generally overestimates the upper part of the ionosphere whereas it underestimates the lower part of the ionosphere under high solar activity conditions. In a first order correction this systematic deviation could be compensated by introducing a height dependence correction factor in IRI profiling

Forecast of Total Electron Content over Europe for disturbed ionospheric Conditions

A general picture of the occurrence of ionospheric storms as function of local time, season and location is known from numerous studies over the past 50 years. Nevertheless, it is not yet possible to say how the ionosphere will actually respond to a given space weather event because the measurements of the onset time, location of maximum perturbation, amplitude and type of storm (positive or negative) deviate much from the climatology. However, statistical analyses of numerous storm events observed in the Total Electron Content (TEC) since 1995 enable to estimate and predict a most probable upcoming perturbed TEC over Europe based on forecasts of geomagnetic activity. A first approach will be presented here. The forecast of perturbed TEC is part of the Forecast System Ionosphere build under the umbrella of the FP7 project AFFECTS∗ (Advanced Forecast For Ensuring Communication Through Space). It aims to help users mitigating the impact on communication system

A new global model for the ionospheric F2 peak height for radio wave propagation

The F2-layer peak density height <I>hm</I>F2 is one of the most important ionospheric parameters characterizing HF propagation conditions. Therefore, the ability to model and predict the spatial and temporal variations of the peak electron density height is of great use for both ionospheric research and radio frequency planning and operation. For global <I>hm</I>F2 modelling we present a nonlinear model approach with 13 model coefficients and a few empirically fixed parameters. The model approach describes the temporal and spatial dependencies of <I>hm</I>F2 on global scale. For determining the 13 model coefficients, we apply this model approach to a large quantity of global <I>hm</I>F2 observational data obtained from GNSS radio occultation measurements onboard CHAMP, GRACE and COSMIC satellites and data from 69 worldwide ionosonde stations. We have found that the model fits to these input data with the same root mean squared (RMS) and standard deviations of 10%. In comparison with the electron density NeQuick model, the proposed Neustrelitz global <I>hm</I>F2 model (Neustrelitz Peak Height Model – NPHM) shows percentage RMS deviations of about 13% and 12% from the observational data during high and low solar activity conditions, respectively, whereas the corresponding deviations for the NeQuick model are found 18% and 16%, respectively

TRANSMIT: Training Research and Applications Network to Support the Mitigation of Ionospheric Threats

TRANSMIT is an initiative funded by the European Commission through a Marie Curie Initial Training Network (ITN). Main aim of such networks is to improve the career perspectives of researchers who are in the first five years of their research career in both public and private sectors. In particular TRANSMIT will provide a coordinated program of academic and industrial training, focused on atmospheric phenomena that can significantly impair a wide range of systems and applications that are at the core of several activities embedded in our daily life. TRANSMIT deals with the harmful effects of the ionosphere on these systems, which will become increasingly significant as we approach the next solar maximum, predicted for 2013. Main aim of the project is to develop real time integrated state of the art tools to mitigate ionospheric threats to Global Navigation Satellite Systems (GNSS) and several related applications, such as civil aviation, marine navigation and land transportation. The project will provide Europe with the next generation of researchers in this field, equipping them with skills developed through a comprehensive and coordinated training program. Theirs research projects will develop real time integrated state of the art tools to mitigate these ionospheric threats to GNSS and several applications that rely on these systems. The main threat to the reliable and safe operation of GNSS is the variable propagation conditions encountered by GNSS signals as they pass through the ionosphere. At a COST 296 MIERS (Mitigation of Ionospheric Effects on Radio Systems) workshop held at the University of Nottingham in 2008, the establishment of a sophisticated Ionospheric Perturbation Detection and Monitoring (IPDM) network (http://ipdm.nottingham.ac.uk/) was proposed by European experts and supported by the European Space Agency (ESA) as the way forward to deliver the state of the art to protect the range of essential systems vulnerable to these ionospheric threats. Through a set of carefully designed research work packages TRANSMIT will be the enabler of the IPDM network. The goal of TRANSMIT is therefore to provide a concerted training programme including taught courses, research training projects, secondments at the leading European institutions, and a set of network wide events, with summer schools, workshops and a conference, which will arm the researchers of tomorrow with the necessary skills and knowledge to set up and run the proposed service. TRANSMIT will count on an exceptional set of partners, encompassing both academia and end users, including the aerospace and satellite communications sectors, as well as GNSS system designers and service providers, major user operators and receiver manufacturers. TRANSMIT's objectives are: A. Develop new techniques to detect and monitor ionospheric threats, with the introduction of new prediction and forecasting models, mitigation tools and improved system design; B. Advance the physical modeling of the underlying processes associated with the ionospheric plasma environment and the knowledge of its influences on human activity; C. Establish a prototype of a real time system to monitor the ionosphere, capable of providing useful assistance to users, which exploits all available resources and adds value for European services and products; D. Incorporate solutions to this system that respond to all end user needs and that are applicable in all geographical regions of European interest (polar, high and mid-latitudes, equatorial region). TRANSMIT will pave the way to establish in Europe a system capable of mitigating ionospheric threats on GNSS signals in real tim