Accession Number : AD0902023

Title :   Development of a VLF Atmospheric Noise Prediction Model.

Descriptive Note : Final rept.,

Corporate Author : WESTINGHOUSE ELECTRIC CORP BOULDER CO GEORESEARCH LAB

Personal Author(s) : Maxwell, Eugene L. ; Stone, Donald L. ; Croghan, Roland D. ; Ball, Lawrence ; Watt, Arthur D.

Report Date : 30 JUN 1970

Pagination or Media Count : 268

Abstract : This report describes the development of a digital computer model for predicting the characteristics of VLF atmospheric noise. Five algorithms which form the basis for the model are: (1) An algorithm for computing electromagnetic power radiated from every region of the earth; (2) An algorithm for computing the standard deviation of power radiated for every region of the earth; (3) An algorithm for the propagation of energy within the earth-ionosphere waveguide; (4) An algorithm which uses the results of 1, 2, and 3 to compute noise field intensities (E sub v), standard deviations (sigma N), V sub d's and direction of arrival values for any location on the earth's surface, for any hour, any month and at any frequency from 10 to 30 kHz. (5) An algorithm to take the output of 4 and prepare contour plots, polar plots, diurnal plots, frequency interpolation plots and data inputs to computer programs for communications system analysis. The prediction model was used to compute E sub v, sigma N and V sub d at 20 kHz, in a 1 kHz bandwidth, for every 10 degrees longitude and every 10 degrees latitude (from 80 degrees S to 80 degrees N). These were computed for each hour and month and were used in the preparation of contours for noise prediction maps. The calculations, contour plots, etc. were used in the preparation of a VLF atmospheric noise prediction manual to be published by the United States Government. Calculated values from the prediction model were compared with measured values of E sub v and generally agreed with + or - 3 dB; sigma N within + or - 1 dB; and V sub d within + or - 2 dB. (Author)

Descriptors :   (*ATMOSPHERICS, MATHEMATICAL PREDICTION), VERY LOW FREQUENCY, COMPUTER PROGRAMS, IONOSPHERIC DISTURBANCES, ELECTRIC FIELDS, VOLTAGE, DAWN CHORUS, WHISTLERS, ALGORITHMS, GEOMAGNETISM, THUNDERSTORMS, LIGHTNING, COMMUNICATION AND RADIO SYSTEMS, INTERFERENCE, MATHEMATICAL MODELS, MAPPING, DIURNAL VARIATIONS, PERIODIC VARIATIONS, FLOW CHARTING, INTENSITY.

Subject Categories : Atmospheric Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE