Showing papers on "TEC published in 1986"
TL;DR: In this article, coordinated measurements of F region plasma patches were conducted on February 3/4, 1984, from Thule and Sondrestrom, Greenland, for the first time these patches were directly tracked flowing in the antisunward direction over distances of 3000 km from the center of the polar cap to the poleward edge of the auroral oval.
Abstract: Coordinated measurements of F region plasma patches were conducted on February 3/4, 1984, from Thule and Sondrestrom, Greenland. Optical, ionosonde, amplitude scintillation, total electron content (TEC), and incoherent scatter radar measurements were combined to reveal several new aspects of the structure and transport of these localized regions of enhanced F region ionization. For the first time these patches were directly tracked flowing in the antisunward direction over distances of 3000 km from the center of the polar cap to the poleward edge of the auroral oval. Quantitative measurements of TEC show increases of 10--15 TEC units within the patches, above a background polar cap value of 5 TEC units. Amplitude scintillation measurements show the presence of ionospheric irregularities through the entire patch, with a weak indication of stronger scintillation on the trailing (or E x B unstable) edge.
174 citations
TL;DR: In this article, seasonal and solar cycle variations of the various characteristics of night-time anomalous enhancements in total electron content (TEC) of the ionosphere were presented for a low latitude station, Hawaii by considering TEC data for a full solar cycle.
Abstract: Seasonal and solar cycle variations of the various characteristics of night-time anomalous enhancements in total electron content (TEC) of the ionosphere are presented for a low latitude station, Hawaii by considering TEC data for a full solar cycle. All the characteristics of the TEC enhancements have seasonal and solar cycle dependence. TEC enhancement characteristics such as frequency of occurrence, amplitude and duration are positively correlated with solar activity. The possible source mechanisms for the observed enhancements are also discussed.
16 citations
TL;DR: In this paper, total electron content (TEC) data were collected from mid-latitude stations and from Macquarie Island in the southern auroral zone, using the Faraday rotation of geostationary satellite signals.
Abstract: During 1984 total electron content (TEC) data were gathered from Melbourne, a mid-latitude station, and from Macquarie Island in the southern auroral zone, using the Faraday rotation of geostationary satellite signals. Large-scale fluctuations in the TEC due to auroral activity were observed from Macquarie Island, and some of these disturbances were seen to propagate towards Melbourne with speeds of 200 to 1,000 m/s. Large-scale rapid decreases in TEC were observed during the evening hours of about one third of autumn equinox days studied. These decreases occurred at a geomagnetic latitude of approximately 60°S and could be associated with the main ionospheric trough travelling through the ray path from the satellite to the receiving station.
4 citations
01 Jan 1986
TL;DR: The first measurements of absolute TEC (Total Electron Content) were made from the polar cap station located at Thule, Greenland in early 1984 using dual-frequency group delay measurements from high orbit satellites as mentioned in this paper.
Abstract: : Measurements of absolute TEC (Total Electron Content), were made for the first time from the polar cap station located at Thule, Greenland in early 1984 using dual-frequency group delay measurements from high orbit satellites. Measurements of L-band amplitude scintillation and dual-frequency differential carrier phase scintillation were also made. The variability of the TEC was extremely large, with increases above the background values of more than 100 percent observed frequently. Quasi-periodic TEC enhancements with periods as short as 10 min and with amplitudes exceeding 10**17 el/m**2 column were seen over several time intervals of more than two hours. The absolute values of TEC observed in the dark polar cap ionosphere at times exceeded the diurnal maximum values from the mid-latitude ionosphere during this initial period of observations. Keywords: Polar ionosphere.
3 citations
01 Jan 1986
TL;DR: In this article, TEC values calculated with the Bent model were used instead of actual data for the Madrid Deep Space Communications Complex during most of the Voyager Uranus approach and encounter.
Abstract: TEC values calculated with the Bent model were used instead of actual data for the Madrid Deep Space Communications Complex during most of the Voyager Uranus approach and encounter. These values were used from December 1, 1985 to January 16, 1986 for Voyager Uranus, and for March 1986 to support the Pathfinder mission; thus, the Halley flybys of Vega 1 and 2 and Giotto were included. Provided sunspot numbers are below 130, the Bent model can be used with confidence to calculate TEC values for midlatitude stations when actual TEC data or monthly averages are not available.
1 citations
1 citations
TL;DR: Faraday observations were conducted at Anchorage, AK using beacon transmissions from a geostationary satellite during the period just following the minimum phase of solar cycle 21, and, for comparison purpose, during a short period following the maximum phase of that same cycle as discussed by the authors.
Abstract: Faraday observations were conducted at Anchorage, AK ( 61.04\deg N, 149.75\deg W), utilizing beacon transmissions from a geostationary satellite during the period just following the minimum phase of solar cycle 21, and, for comparison purpose, during a short period following the maximum phase of that same cycle. Near the minimum phase average maximum monthly values of total electron content (TEC), which is proportional to transionospheric signal time delay, were below 15 \times 10^{16} el m-2, while individual daily maximum values never exceeded 20 \times 10^{16} el m-2. Near the maximum phase TEC average monthly values were larger by a factor of two. Seasonal and day-to-day variabilities were observed. Unique representation of the data has permitted the study of day-to-day variability of TEC. For example, near minimum phase during all seasons the TEC structure appears uniform from day to day during the buildup and decay phases of the local ionosphere. During the maximum and minimum of the diurnal phase, the TEC structure variability is seasonally dependent. During periods of magnetic sudden commencements, which rarely occurred in the observation periods, significant positive phase responses of TEC did not materialize near solar minimum, but were correlated near solar maximum.
1 citations
TL;DR: In this article, the authors used a focused laser beam for determining the location of the most sensitive point on the surface of the TEC jacket and a defocused beam in estimating the thermal inertia of a TEC.
Abstract: This paper considers the question of measuring the thermal inertia of cable-type thermoelectric converters (TEC). Therse converters are manufactured by using thermocouple cables with mineral insulation. In order to improve the accuracy of the measurement, it is possible to use apparatuses operating by the heating0grid method or the shutter method. The scheme of placement of the measurement points on the end surface of the TEC is shown. The procedure presented determines the thermal inertia of TEC's by a pulsed method. The criteria used for estimating the thermal inertia of the TEC's was the time required for reaching the maximum value of the thermal-emf pulse. It is expedient to use a focused laser beam for determining the location of the most sensitive point on the surface of the TEC jacket and a defocused beam in estimating the thermal inertia of the TEC.