Publication Date


Document Type


First Advisor

ReVelle, Douglas O.

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Geography


Jet stream--Illinois


An observational study was carried out during the Winter and Spring seasons of 1991 in an attempt to gain information on mid-latitude nocturnal low-level jets. Seasonal characteristics were analyzed. The source of data for this study included hourly single-pilot balloon launches. In addition, synoptic scale information was available through our campus-based weather office and the PC-MCIDAS, Unidata system. Observational periods were chosen on the basis of a series of quantitative criteria that attempted to ascertain the state of the planetary boundary layer and its ability to generate nocturnal jets locally. Finally, the multi-level nocturnal low-level jet model of ReVelle, Logsdon, and Liu (1990) was utilized to compare the observational data against a theoretical prediction of the planetary boundary layer winds. Theoretical options that were tested were: a) a time- independent barotropic mode, b) a time-dependent barotropic modes with geostrophic winds changing with periods of 17.9 hours (1 local inertial period) and 12 hours, c) a barotropic mode with advection terms, and, d) a baroclinic mode. A detailed quantitative comparison between our observations and theory is presented.


Includes bibliographical references (pages [157]-163)


xiii, 175 pages




Northern Illinois University

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