Accession Number : AD0262510

Title :   DEVELOPMENT PROCESSES ASSOCIATED WITH THE FORMATION AND MOVEMENT OF AN ALBERTA CYCLONE

Corporate Author : CHICAGO UNIV ILL

Personal Author(s) : BONNER,WILLIAM D.

Report Date : APR 1961

Pagination or Media Count : 1

Abstract : The contributions of vorticity advection aloft, horizontal thermal (thickness) advection, and indirectly the patterns of heating or cooling associated with vertical motion are computed for successive times during the initial formation and subsequent eastward movement of a typical Alberta cyclone. At the onset of cyclogenesis, vorticity advection aloft contributed little to the development, but assumed greater importance in later stages. Thermal advection was importantAT ALL TIMES IN DETERMINING THE LARGE-SCALE CHANGES IN LOWER LEVELS. The region of lowlevel production of vorticity associated with the Rocky Mountains is very limited, but vorticity generated in this region spreads eastward over a larger area by horizontal advection. Surface cyclogenesis stops as soon as the surface front enters the low center. The importance of orographic influences evidently lies in the initial production of a locally intense trough, tuned to the scale of the Rocky Mountains and well ahead of the frontal trough associated with the parent cyclone, wherein circulation can be intensified on the approach of an upper-level divergence field. After the cyclone had moved away from the Rockies, horizontal thermal advection and advection of vorticity aloft were the important processes. (Author)

Descriptors :   *AIR MASS ANALYSIS, *CYCLONES, CLIMATE, CONVECTION, INTENSITY, MATHEMATICAL ANALYSIS, METEOROLOGY, MOTION, MOUNTAINS

Distribution Statement : APPROVED FOR PUBLIC RELEASE