Pakistan Research Repository


Sheikh, Noor Muhammad (1975) INTRODUCTION OF SATELLITE DATA INTO F-2 LAYER MODELS. PhD thesis, University of Engineering & Technology, Lahore.



F2-layer peak electron densities were derived from the in-situ measurements of electron density by the 'Impedance Probe' and the 'Retarding Potential Analyzer' experiments on board the AEROS-A and B satellites. Bens ionospheric profiles were used for height reduction. Global latitudinal and longitudinal variations of the peak density are given at two fixed local times. Comparisons are made with the predictions from the existing CCIR numerical map. Within the accuracy in the height reduction procedure, the agreement is found to be good over the continental areas, but important differences are observed over the oceans. The longitudinal variations are in general larger then given in the CCIR model. At mid-latitudes and at the equator, the trend of the CCIR longitudinal variation is maintained rather well, but at high and lower latitudes, the differences are large. In the southern hemisphere, the form of the variations is not correctly reproduced and over the oceans, particularly over the pacific, differences of the order of 100 % do occur. In the South Atlantic Anomaly region, latitudinal gradients larger than those given by the CCIR model are shown to exist and the values of the electron densities at night are higher than proposed by the CCIR map. Other models such as that of CHING and CHIU are shown to produce even larger over-smoothing of the important latitudinal and longitudinal trends and are therefore worse than the CCIR compilation, which at present seems to be the best available. Global model for day and night are given using a similar. Set of mathematical functions as used in the development of the, CCIR numerical maps, but using the local time instead of the universal time. Suggestions are made for improvements in the CCIR numerical maps. The height of the peak of the F2-layer is an important parameter and also plays a critical role when deriving peak densities from in-situ measurements. A critical review is made of the existing models of the peak height and an improved global model compatible with satellite and incoherent-scatter data is given. The present work attempts to make a step forward in the field of Aeronomy and Radio Propagation. New results about the longitudinal variations on a global basis based on satellite observations were found. The earlier techniques could not investigate such features because ground stations were practically absent over the oceanic regions.

Item Type:Thesis (PhD)
Uncontrolled Keywords:aeros-satellites, f2-layer, half-thickness, electron densities, ccir numerical map, aeronomy
Subjects:Engineering & Technology (e) > Engineering(e1) > Electrical engineering (e1.16)
ID Code:430
Deposited By:Mr. Muhammad Asif
Deposited On:28 Sep 2006
Last Modified:04 Oct 2007 21:00

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