The occurrence of the mid-latitude ionospheric trough in GPS-TEC measurements

Krankowski, Andrzej; Шагимуратов, И. И.; Ephishov, I.I.; Krypiak-Gregorczyk, Anna; Yakimova, G. A.

doi:10.1016/j.asr.2008.05.014

Cited by 39 publications

(55 citation statements)

References 23 publications

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“…The ionospheric trough, characterized by very low values of N e , is so well detected under disturbed conditions by Swarm satellites because, as shown by Krankowski et al (2009), it significantly depends on the geomagnetic activity. In fact, under disturbed conditions, the ionospheric trough tends to exhibit much lower values of electron density than for quiet conditions.…”

Section: Resultsmentioning

confidence: 95%

Comparison between IRI and preliminary Swarm Langmuir probe measurements during the St. Patrick storm period

et al. 2016

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Preliminary Swarm Langmuir probe measurements recorded during March 2015, a period of time including the St. Patrick storm, are considered. Specifically, six time periods are identified: two quiet periods before the onset of the storm, two periods including the main phase of the storm, and two periods during the recovery phase of the storm. Swarm electron density values are then compared with the corresponding output given by the International Reference Ionosphere (IRI) model, according to its three different options for modelling the topside ionosphere. Since the Swarm electron density measurements are still undergoing a thorough validation, a comparison with IRI in terms of absolute values would have not been appropriate. Hence, the similarity of trends embedded in the Swarm and IRI time series is investigated in terms of Pearson correlation coefficient. The analysis shows that the electron density representations made by Swarm and IRI are different for both quiet and disturbed periods, independently of the chosen topside model option. Main differences between trends modelled by IRI and those observed by Swarm emerge, especially at equatorial latitudes, and at northern high latitudes, during the main and recovery phases of the storm. Moreover, very low values of electron density, even lower than 2 × 10 4 cm −3, were simultaneously recorded in the evening sector by Swarm satellites at equatorial latitudes during quiet periods, and at magnetic latitudes of about ±60° during disturbed periods. The obtained results are an example of the capability of Swarm data to generate an additional valuable dataset to properly model the topside ionosphere.

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Section: Resultsmentioning

confidence: 95%

Comparison between IRI and preliminary Swarm Langmuir probe measurements during the St. Patrick storm period

et al. 2016

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“…It then moves progressively equatorward through the night reaching its most equatorward latitude in pre-dawn hours. With the increasing sunlight at dawn, ionization production results in increased densities in the trough and the apparent rapid retreat of the feature to higher latitudes with the trough minimum being typically at 65 • corrected geomagnetic latitude at 08:00 LT in the results of Krankowski et al (2009). A large-scale trough also features in the post-noon high-latitude dayside ionosphere (Kersley et al, 1997).…”

Section: Introductionmentioning

confidence: 99%

“…The characteristics are elongated in longitude. When observed in Europe, as for example by Krankowski et al (2009), the feature normally first occurs in late afternoon at latitudes poleward of 60 • latitude. It then moves progressively equatorward through the night reaching its most equatorward latitude in pre-dawn hours.…”

Section: Introductionmentioning

confidence: 99%

“…Methods of observation include the following: ionospheric sounders such as the networks considered by Whalen (1987Whalen ( , 1989; incoherent scatter radar, which can reveal the latitudinal structure of the trough and associated ionization temperature characteristics (Voiculescu et al, 2010); satellite TEC observations, for example by the Navy Ionospheric Monitoring System, NIMS (Kersley et al, 2004); and ionospheric tomography reconstruction using NIMS TEC observations . In more recent years TEC measurements using GPS radio transmissions have been used to observe and study the trough, for example Krankowski et al (2009) who used GPS observations from a network of receiving stations in Europe. Each of the observing techniques has its strengths and limitations.…”

Section: Introductionmentioning

confidence: 99%

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Modelling the main ionospheric trough using the Electron Density Assimilative Model (EDAM) with assimilated GPS TEC

et al. 2018

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Abstract. The main ionospheric trough is a large-scale spatial depletion in the electron density distribution at the interface between the high-and mid-latitude ionosphere. In western Europe it appears in early evening, progresses equatorward during the night, and retreats rapidly poleward at dawn. It exhibits substantial day-to-day variability and under conditions of increased geomagnetic activity it moves progressively to lower latitudes. Steep gradients on the trough-walls on either side of the trough minimum, and their variability, can cause problems for radio applications. Numerous studies have sought to characterize and quantify the trough behaviour.The Electron Density Assimilative Model (EDAM) models the ionosphere on a global scale. It assimilates observations into a background ionosphere, the International Reference Ionosphere 2007 (IRI2007), to provide a full 3-D representation of the ionospheric plasma distribution at specified times and days. This current investigation studied the capability of EDAM to model the ionosphere in the region of the main trough. Total electron content (TEC) measurements from 46 GPS stations in western Europe from September to December 2002 were assimilated into EDAM to provide a model of the ionosphere in the trough region. Vertical electron content profiles through the model revealed the trough and the detail of its structure. Statistical results are presented of the latitude of the trough minimum, TEC at the minimum and of other defined parameters that characterize the trough structure. The results are compared with previous observations made with the Navy Ionospheric Monitoring System (NIMS), and reveal the potential of EDAM to model the large-scale structure of the ionosphere.

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“…The current maps are only available days later and have a temporal resolution of 2 hours and a spatial resolution of 2.5 x 2.5 degrees, but for the trigger real-time data is required. However, the Space Radio-Diagnostics Research Centre of the University of Warmia and Mazury and the UPC-IonSAT research group of the Technical University of Catalonia are currently developing algorithms to provide real-time high resolution TEC maps, specifically for the ILT (International LOFAR Telescope), using 119 Euref Permanent Network stations [11][12][13]. In the result, near real-time and high-spatial resolution maps are obtained at 15 minutes in temporal resolution and 0.5 degree in latitudinal and longitudinal spatial resolution, (Fig.…”

Section: Ionospheric Correctionsmentioning

confidence: 99%

TEC, Trigger and Check, preparing LOFAR for Lunar observations

et al. 2017

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Abstract. One of the main ways to use radio to detect Ultra High Energy Neutrinos and Cosmic Rays is the Lunar Askaryan technique, that uses the Moon as a target and searches for nanosecond pulses with large radio telescopes. To use low frequency aperture arrays, such as LOFAR and the SKA, pose new challenges and possibilities in detection techniques of short radio pulses and to measure the Total Electron Content (TEC). As a prepatory work, we have used other measurements that use similar techniques, or that can answer a specific question, with the LOFAR radio telescope. This contribution reports on our work on triggering on short radio signals, post-event imaging of radio signals from buffered data and methods to determine the TEC-value.

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The occurrence of the mid-latitude ionospheric trough in GPS-TEC measurements

Cited by 39 publications

References 23 publications

Comparison between IRI and preliminary Swarm Langmuir probe measurements during the St. Patrick storm period

Comparison between IRI and preliminary Swarm Langmuir probe measurements during the St. Patrick storm period

Modelling the main ionospheric trough using the Electron Density Assimilative Model (EDAM) with assimilated GPS TEC

TEC, Trigger and Check, preparing LOFAR for Lunar observations

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