Topic
TEC
About: TEC is a research topic. Over the lifetime, 5119 publications have been published within this topic receiving 84696 citations.
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TL;DR: In this article, the global ionospheric total electron content (TEC) with the analysis of empirical orthogonal functions (EOF) was modeled with the obtained statistical eigen modes, which consisted of two factors: the eigen vectors mapping TEC patterns at latitude and longitude (or local time LT), and corresponding coefficients displaying the TEC variations in different time scales.
Abstract: In the present work we model the global ionospheric total electron content (TEC) with the analysis of empirical orthogonal functions (EOF). The obtained statistical eigen modes, which makeup the modeled TEC, consist of two factors: the eigen vectors mapping TEC patterns at latitude and longitude (or local time LT), and the corresponding coefficients displaying the TEC variations in different time scales, i.e., the solar cycle, the yearly (annual and semiannual) and the diurnal universal time variations. It is found that the EOF analysis can separate the TEC variations into chief processes and the first two modes illustrate the most of the ionospheric climate properties. The first mode contains both the semiannual component which shows the semiannual ionospheric anomaly and the annual component which shows the annual or non-seasonal ionospheric anomaly. The second mode contains mainly the annual component and shows the normal seasonal ionospheric variation at most latitudes and local time sectors. The annual component in the second mode also manifests seasonal anomaly of the ionosphere at higher mid-latitudes around noontime. It is concluded that the EOF analysis, as a statistical eigen mode method, is resultful in analyzing the ionospheric climatology hence can be used to construct the empirical model for the ionospheric climatology.
50 citations
TL;DR: Thrombotic and embolic complication was not uncommon; risk factors for TEC were APC and atrial arrhythmias; most patients were treated successfully with warfarin alone.
50 citations
TL;DR: In this paper , the authors analyzed data from the nearest ground-based receivers of Global Navigation Satellite System to explore the ionospheric total electron content (TEC) response to the Hunga Tonga-Hunga Ha'apai submarine volcano eruption.
Abstract: On 15 January 2022, the Hunga Tonga-Hunga Ha’apai submarine volcano erupted violently and triggered a giant atmospheric shock wave and tsunami. The exact mechanism of this extraordinary eruptive event, its size and magnitude are not well understood yet. In this work, we analyze data from the nearest ground-based receivers of Global Navigation Satellite System to explore the ionospheric total electron content (TEC) response to this event. We show that the ionospheric response consists of a giant TEC increase followed by a strong long-lasting depletion. We observe that the explosive event of 15 January 2022 began at 04:05:54UT and consisted of at least five explosions. Based on the ionospheric TEC data, we estimate the energy released during the main major explosion to be between 9 and 37 Megatons in trinitrotoluene equivalent. This is the first detailed analysis of the eruption sequence scenario and the timeline from ionospheric TEC observations.
50 citations
TL;DR: In this paper, the authors developed an algorithm for DCB estimation from the data of a single GPS/GLONASS station, which was compared with the oblique TEC correction by using CODE laboratory DCB data.
Abstract: When determining the absolute oblique total electron content (TEC) of the ionosphere using both GLONASS/GPS code and phase measurements, there occurs a systematic error associated with the differential code biases (DCBs). A 1-ns DCB leads to the ∼2.9 TECU error when determining L1-L2 dual-frequency oblique TEC. We have developed an algorithm for DCB estimation from the data of a single GPS/GLONASS station. Presented are the results of the algorithm operation compared with the oblique TEC correction by using CODE laboratory DCB data.
49 citations
TL;DR: In this paper, an overview of the existing results of comparisons between the IRI-90 predictions and the observational data for the Brazilian longitude sector and attempts to place the major findings in a global perspective.
49 citations