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Effects of miso- and mesoscale obstructions on PAM winds obtained during project NIMRODData from 27 PAM (Portable Automated Mesonet) stations, operational as a phase of project NIMROD (Northern Illinois Meteorological Research on Downburst), are presented. It was found that PAM-measured winds are influenced by the mesoscale obstruction of the Chicago metropolitan area, as well as by the misoscale obstruction of identified trees and buildings. The mesoscale obstruction was estimated within the range of near zero to 50%, increasing toward the city limits, while the misoscale obstruction was estimated as being as large as 58% near obstructing trees which were empirically calculated to cause a wind speed deficit 50-80 times their height. Despite a statistical analysis based on one-million PAM winds, wind speed and stability transmission factors could not be accurately calculated; thus, in order to calculate the airflow free from obstacle, PAM-measured winds must be corrected.
Document ID
19820057717
Document Type
Reprint (Version printed in journal)
Authors
Fujita, T. T.
(Chicago Univ. Chicago, IL, United States)
Wakimoto, R. M.
(Chicago, University Chicago, IL, United States)
Date Acquired
August 10, 2013
Publication Date
June 1, 1982
Publication Information
Publication: Journal of Applied Meteorology
Volume: 21
Subject Category
Meteorology And Climatology
Funding Number(s)
CONTRACT_GRANT: NSF ATM-79-21260
CONTRACT_GRANT: NOAA-NA-80AAD001
CONTRACT_GRANT: NRC-04-74-239
CONTRACT_GRANT: NGR-14-001-008
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Public
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