Vertical temperature structure of Calgary's urban heat island
The construction of cities measurably alters the climate of their environment. These changes are expressed both near the ground surface and up to levels of the order of 100 m above the city. Urban heat island is the phrase applied to the air layer which experiences temperature changes resulting from urbanization. Temperatures near the surface are at a maximum in the downtown and industrial areas. The difference between urban and rural temperatures is dependent on cultural elements such as building density and anthropogenic heat and meteorological factors such as mixing depth and wind speed. The build-up of heat near the city surface also influences vertical temperature profiles. Stability is decreased and many times inversions are destroyed over cities. This study attempts to expand the understanding of the urban heat island near the surface to its behavior in the lower several hundred meters of the atmosphere. This is accomplished by using data collected by instrumented helicopter, some of which were available before the study, and other data which were collected particularly for this study. Ancillary data sources include radiosondes, pibals, thermographs, anemometers, instrumented tower, and air quality instrumentation. These data are used to define mean temperature profiles in Calgary's urban heat island and the frequencies of various types of profiles in different areas of the city. Maximum instability is associated with the inner city while mean mixing depths are highest over the downtown and industrial areas. The analysis of temporal variability of temperature structure points to a very stable lower atmosphere from late afternoon to late morning on most days during winter at Calgary. The analysis showed that stability in the lower atmosphere is greatest during chinook weather as compared to cyclonic and anticyclonic activity. Suggestions for further study and implementation of present knowledge are outlined.
Bibliography: p. 138-144.
Leggat, K. R. (1978). Vertical temperature structure of Calgary's urban heat island (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/17199