Date of Award
Master of Arts
Dr. Val L. Eichenlaub
Rainer R. Erhart
Masters Thesis-Open Access
Climate and the City
Studies made of temperature in and around cities have shown the climate of the city to be anomalous in relation to its regional climate. The extent of this anomalous condition and the reasons for its occurrence vary from city to city and from season to season. So many variable factors are present in the generation or regeneration of heat within the city that no study has yet satisfactorily explained the total factors involved, or has indicated the percentage for which any one factor might be responsible. This being the case, the only objective investigation that can be carried out, without breaking new ground or lapsing into pure conjecture, is to delimit the extent of the anomaly and observe the spacial distribution of its seasonal variations.
The anomaly that does exist is one most commonly represented by higher temperatures within the city than those temperatures recorded in the surrounding countryside. In many cities such differences have been dismissed as being products of the variations in thermometer siting. However, research has shown that given to location that have the same physical landforms and experience the same external climatic factors, and assuming one is in its natural, undistributed state while the other is a sizeable modern city, the interaction between the individual locations and the external influences acting upon them will be noticeably different. The city, therefore, becomes a modifier of climate, and in particular, temperature. During the winter the city experiences less severe temperatures then the surrounding countryside and in the summer it experiences greater temperatures than the nearby rural areas. The degree to which these variations are present in a city will depend upon the location of the city, its size, its function, and the external climatic factors of the region.
There are three basic causes for the changes in temperature when an area becomes urbanized. The first is the alteration in surface. This may be very radical as in the case of the removal of dense forest and the construction of stone, brick and cement edifices. Moist areas such as swamps and ponds may be drained and aerodynamic changes will probably occur due to the variety of structures built. Secondly, the city itself produces heat in various ways ranging from that produced by factories, home furnaces, and automobile engines down to that produced by the human and animal metabolisms. Finally, there are released into the atmosphere over the city large volumes of inert solid matter, gases, and active chemicals which, apparently, can affect the climate even beyond the city's confines.1 At no point in this study were these factors analyzed or isolated so that the phrase "city heat" refers to the temperature resulting from any combination of these variables and others which are not so easily identified.
Smith, Allen R., "An Investigation of the Surface Temperature Distribution in the Detroit Region" (1966). Master's Theses. 4280.