A Method of Predicting the Frequency Distribution of Windchill
A Method of Predicting the Frequency Distribution of Windchill

Author:

Publisher:

Published: 1961

Total Pages: 1

ISBN-13:

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EIGHT YEARS OF SIMULTANEOUS RECORDINGS OF JANUARY TEMPERATURE AND WINDSPEED FROM 20 NORTH AMERICAN STATIONS ARE USED IN THE DEVELOPMENT OF A METHOD FOR PREDICTING THE PERCENTAGE OF TIME WINDCHILL WILL LIE ABOVE OR BELOW A GIVEN VALUE. A WINDCHILL PREDICTION CHART IS CONSTRUCTED. IT COMBINES THE SIPLE NOMOGRAM, USED TO DERIVE THE WINDCHILL INDEX BASED ON AVERAGE TEMPERATURE AND WINDSPEED, AND THE PREDICTION MODEL BASED ON THE WINDCHILL FREQUENCIES. PREDICTION ERRORS (RANGE 0 - 240WINDCHILL UNITS, WITH AVERAGE OF 52) PRODUCE A SKEWED DISTRIBUTION WITH 64(OF THE ERRORS LESS THAN THE AVERAGE. ERRORS GREATER THAN AVERAGE ARE CONCENTRATED BETWEEN THE 5TH AND 30TH AND BEYOND THE 95TH PERCENTILES. MAGNITUDE OF ERROR INCREASES AS THE INDEX INCREASES. THE RELIABILITY OF THE PREDICTION CHART IS TESTED BY FREQUENCY RECORDS FROM 34 ADDITIONAL STATIONS. DEVIATIONS OF ACTUAL WINDCHILL VALUES FROM THE PREDICTIONS ARE, ON THE AVERAGE, 20 WINDCHILL UNITS GREATER THAN DEVIATIONS IN THE MODEL. THE SAME GENERAL PATTERN OF ERROR DEVIATION IS OBSERVED.

Earth Science Applied to Military Use of Natural Terrain
Earth Science Applied to Military Use of Natural Terrain

Author: Stanley M. Needleman

Publisher:

Published: 1969

Total Pages: 220

ISBN-13:

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A survey of the state-of-the-art in the evaluation of natural terrain by earth-science techniques and measurement systems is presented in response to a need that existed for many years. This report considers the terrain as an envelope of the environment and all related parameters that are basic in an evaluation for relevant military applications such as unimproved landing areas, trafficability, site selection for operational facilities, terrain reconnaissance and surveillance, and target detection within a masked terrain complex. Methods of terrain-data acquisition, analysis, and evaluation and their limitations are reviewed. The status of research and development, specifying the gaps in technology, is summarized with accompanying conclusions. The report forecasts the requirement for an automated terrain-data acquisition, storage, and display system. Information pertaining to the classification of terrain data, field devices to measure bearing strength, and a visualized optimum remote sensing system is also given in the appendix. A glossary and a comprehensive bibliography are included. (Author).