Abstract |
The dynamical effects of an urban surface on the airflow above it could be an important factor in meso-scale precipitation patterns. In order to evaluate the dynamical influences of an urban area, local variations in the mixing layer depth over metropolitan St. Louis are investigated. Variations in the height of a temperature inversion capping a deep mixing layer are used to measure the urban effect on the mixing layer depth. Case studies employing aircraft, pilot balloon and radiosonde data collected in Project METROMEX show that the St. Louis urban area produces a doming of the inversion layer over the city during the morning hours on certain summer days. It is concluded from observational and numerical modeling studies that the urban surface influence did not contribute significantly to the formation of the inversion dome but rather that a major influence existed within the upper regions of the mixing river. (Author) |