Ionospheric research and space weather services

Cander, Ljiljana R.

doi:10.1016/j.jastp.2008.05.010

Cited by 29 publications

(11 citation statements)

References 39 publications

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“…In addition to simple representations of the ionosphere such as Chapman layers, more complicated models also exist. Cander (2008) lists some of the many ionospheric models in existence and summarises: ''Empirical models, like the global IRI model, the NeQuick model, the European region COSTPRIME, and COSTPROF family of models, attempt to extract systematic ionospheric variations from past data records … Physics-based theoretical and/or numerical models attempt to solve a set of first-principles equations for the ionospheric plasma, starting from the continuity, energy, and momentum equations for electrons and ions. … Parametric models simplify the theoretical models by expressing them in terms of solar-terrestrial parameters and geographical locations, giving a realistic representation of the ionospheric spatial and temporal structure using a limited number of numerical coefficients''.…”

Section: Modelling the Ionospherementioning

confidence: 99%

A Review of Higher Order Ionospheric Refraction Effects on Dual Frequency GPS

et al. 2010

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Higher order ionospheric effects are increasingly relevant as precision requirements on GPS data and products increase. The refractive index of the ionosphere is affected by its electron content and the magnetic field of the Earth, so the carrier phase of the GPS L1 and L2 signals is advanced and the modulated code delayed. Due to system design the polarisation is unaffected. Most of the effect is removed by expanding the refractive index as a series and eliminating the first term with a linear combination of the two signals. However, the higher order terms remain. Furthermore, transiting gradients in refractive index at a non-perpendicular angle causes signal bending. In addition to the initial geometric bending term, another term allows for the difference that the curvature makes in electron content along each signal. Varying approximations have been made for practical implementation, mainly to avoid the need for a vertical profile of electron density. The magnetic field may be modelled as a tilted co-centric dipole, or using more realistic models such as the International Geomagnetic Reference Field. The largest effect is from the second term in the expansion of the refractive index. Up to several cm on L2, it particularly affects z-translation, and satellite orbits and clocks in a global network of GPS stations. The third term is at the level of the errors in modelling the second order term, while the bending terms appear to be absorbed by tropospheric parameters. Modelling improvements are possible, and three frequency transmissions will allow new possibilities.

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Section: Modelling the Ionospherementioning

confidence: 99%

A Review of Higher Order Ionospheric Refraction Effects on Dual Frequency GPS

et al. 2010

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“…In order to better classify the complexity of ionosphere that exerted from potential perturbation, a local ionospheric outburst index which will more closely describe the ionospheric disturbances over Malaysia is needed. Numerous regional or national TEC‐based ionospheric indices and near real‐time ionospheric disturbance monitoring systems have been deployed and operationally serving the public in the U.S., Europe and Japan [see Jakowski et al , 2006; Belehaki et al , 2006; Cander , 2008; Fuller‐Rowell et al , 2006; Jakowski et al , 2005; Miyake , 2007; Miyake and Jin , 2009]. However, Leong et al [2010] show that the differential ionospheric residual of baselines from GPS NRTK, which contains local ionosphere information, is a remarkable alternative parameter for deriving ionospheric outburst index.…”

Section: Introductionmentioning

confidence: 99%

ISKANDARnet IOMOS: Near real‐time equatorial space weather monitoring and alert system in Peninsular Malaysia

et al. 2012

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This work proposes ISKANDARnet Ionospheric Outburst MOnitoring and alert System (IOMOS), along with Ionospheric Outburst Index (IOX) to develop an operational near real‐time space weather service for Malaysia. The IOMOS is based on Global Positioning System (GPS) Network‐based Real‐Time Kinematic (NRTK) concept which is by nature for atmospheric (ionosphere and troposphere) modeling within the network coverage. The elegance of this solution lies in the fact that IOMOS utilize differential ionospheric residual from network of GPS baselines which incur no additional cost for operation. Users will be informed about the ionospheric perturbation through Short Message Service (SMS), email or Twitter®. This approach will ultimately beneficial for the navigation and satellite positioning communities, particularly during the coming Solar Cycle 24. In addition, a combination of local and global GPS network has been employed to study the equatorial ionosphere geomorphology and climatology in the Malaysian sector. Equatorial Total Electron Content (TEC) over Malaysia shows semi‐annual, annual, and seasonal variations with maximum values appearing during equinoctial months and minimum during solstices months. The TEC value during vernal equinox is about 21% higher than autumnal equinox, and December solstice exceeds that at the June solstice by around 14%. It is also found that semi‐annual variation is present at all levels of solar activity, whereas June solstice predominates December solstice during high solar activity for annual and seasonal variations. In near future, a near real‐time TEC derivation system will be developed to support equatorial ionosphere modeling to enhance space weather service for Malaysia.

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“…Next applications are under development. Validation of the mapping and forecasting algorithms has been presented by Cander [2008].…”

Section: Scientific Results Applicable For Operational Usementioning

confidence: 99%

Monitoring and modeling of ionospheric characteristics in the framework of European COST 296 Action MIERS

et al. 2010

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[1] The Mitigation of Ionospheric Effects on Radio Systems COST 296 Action is devoted to the mitigation of ionospheric effects on radio systems. It creates a platform for sharing of data, algorithms, models, and jointly developed advanced technologies, the processing chain from measurements, through algorithms, to operational knowledge. This initiative creates a unique possibility for national groups to consolidate the design of a product required for their own activity and for European assessments in the ionosphere and telecommunication area. An important part of the action is to stimulate and integrate many national and international activities which provide tools for global and regional ionospheric monitoring and modeling. The work includes the near-Earth space plasma monitoring, modeling and forecasting, and a study of the upper atmosphere climate. Well-defined terms of reference include developing ground-based and space-borne monitoring techniques and parameters describing the state of ionospheric plasma, maintaining and extending the flow of real-time and retrospective ionospheric monitoring data to databases. To obtain adequate, high-quality information, special attention is paid to the data ingestion and assimilation in constructing ionospheric models of different spatial and time scale perturbations, as well as storms, small variations, and irregularities. The physical origin of atmospheric/ionospheric effects and their signatures and parameters are investigated. Identification criteria are studied and formulated.

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Ionospheric research and space weather services

Cited by 29 publications

References 39 publications

A Review of Higher Order Ionospheric Refraction Effects on Dual Frequency GPS

A Review of Higher Order Ionospheric Refraction Effects on Dual Frequency GPS

ISKANDARnet IOMOS: Near real‐time equatorial space weather monitoring and alert system in Peninsular Malaysia

Monitoring and modeling of ionospheric characteristics in the framework of European COST 296 Action MIERS

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