摘要 :
Results are presented of studies of ionospheric scintillation obtained by monitoring of transmissions from NNSS satellites at Kiruna, Northern Sweden during a two year period from September 1984 to September 1987. Attention is con...
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Results are presented of studies of ionospheric scintillation obtained by monitoring of transmissions from NNSS satellites at Kiruna, Northern Sweden during a two year period from September 1984 to September 1987. Attention is concentrated in this report on phase scintillation morphology. Also presented are results of model studies of the geometrical influences in amplitude and phase scintillations at a high-latitude site aimed at interpreting the observations and understanding the nature of the ionospheric irregularities responsible for the scintillations. Also discussed are results of two coordinated studies of ionospheric irregularities using scintillation observations and data from Hf and VHF backscatter radar systems respectively.
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摘要 :
Progress in computers during the past two decades has sparked the development ofmany useful high frequency (HF) ionospheric propagation prediction codes. The high-latitude (polar) ionosphere still remains as the most difficult pro...
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Progress in computers during the past two decades has sparked the development ofmany useful high frequency (HF) ionospheric propagation prediction codes. The high-latitude (polar) ionosphere still remains as the most difficult propagation region to predict. A 'Noncentric' database of collected high-latitude signal and noise measurements was obtained during 1988 and 1989 by the University of Leicester, U.K. The Advanced Prophet 4.0 HF Ionospheric Propagation Prediction Code was exercised and compared to a portion of the 'Noncentric' database, for a transmitter at Clyde River, Canada and a receiver at Leicester, U.K. The Prophet predictions were better during winter months than during summer months. Overall, 70% of the signal strength data from Prophet 4.0 were between -20 dB and +20 dB error, compared to the measured data.
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This report contains a summary of results obtained from the Rome Air Development Center's modified commercial meteor scatter communications link, located in Greenland. The data presented here were recorded during the months of Oct...
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This report contains a summary of results obtained from the Rome Air Development Center's modified commercial meteor scatter communications link, located in Greenland. The data presented here were recorded during the months of October, November, and December 1986. A known message is repeatedly transmitted between Thule and Sondrestrom AB from which pertinent meteor scatter statistics, such as message waiting times and throughput, are calculated. Such statistics are presented in this paper. Keywords include: Meteor scatter propagation, Meteor scatter high-latitude effects, and Meteor scatter frequency dependence. (RH)
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Total electron content (TEC) observations were made at various midlatitude and high latitude stations using beacon satellite emissions from geostationary satellites. The Faraday rotation technique was utilized in making TEC Measur...
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Total electron content (TEC) observations were made at various midlatitude and high latitude stations using beacon satellite emissions from geostationary satellites. The Faraday rotation technique was utilized in making TEC Measurements during the periods near the minimum and maximum of the current solar cycle. Latitudinal, seasonal, and solar-cycle dependence of TEC were observed with seasonal effects being most consistent. Day-to-day variability of TEC, as expressed by the ratio of the monthly standard deviation of TEC to TEC was found to be approx. 25% for the daytime period irrespective of station position, season or solar cycle epoch. (Author)
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摘要 :
This project s overarching goal is to quantitatively expand our understanding of turbulent mixing processes in high latitude regions of the global ocean. It focuses on high latitudes because: (1) they are primary sites for surface...
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This project s overarching goal is to quantitatively expand our understanding of turbulent mixing processes in high latitude regions of the global ocean. It focuses on high latitudes because: (1) they are primary sites for surface conditioning of deep waters that drive the meridional overturning circulation, a primary component of the mean global ocean circulation, and one that relies on a balance between mixing and other processes; (2) they provide excellent, and in some cases extreme, examples of mixing-related phenomena that are active throughout the world oceans and therefore can broaden our parameter spectrum related to such phenomena; (3) they provide high quality, geophysical scale natural laboratories for field study of these phenomena because of a surface ice cover that stabilizes observation platforms; and (4) these remote areas are data-poor in comparison with the rest of the ocean, despite the importance of quantifying mixing processes and better understanding them within a global context.
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摘要 :
The focus of the study is a region of enhanced ionospheric densities observed by the EISCAT Svalbard radar in the polar F-region near local magnetic noon under conditions of IMF Bz.
