The Urban Heat Island in Akron, Ohio

by FRANK P. MARTIN and GRACE L. POWELL, respectively weather service specialist, National Weather Service, Akron, Ohio; and associate professor of geography, University of Akron, Akron, Ohio.

ABSTRACT.-Data gathered by automobile traverse were used to describe the urban heat of Akron, Ohio. Observations were made at 2100 or 2200 EST on four nights-17 April, 11 July, 10 October, and 2 January. Weather conditions not conducive to heat-island development were avoided. Temperatures in the center of the heat island were 6 to 14°F warmer than rural areas outside the city. The heat-island center was always over a mixed residential/commercial area. Topographic influences were apparent in the heat-island pattern.

MUCHHAS BEEN WRITTEN about time of the traverse runs) to assure a the micro-climatic variations that fair representation of meteorological have been found in some urbanized conditions. However, days with strong areas and hence have been assumed to winds, cloud cover, and precipitation exist in other urban centers as well. The were avoided for data collection because most commonly documented urban im- these conditions weaken or eliminate pact on climate has become widely heat islands. Week nights were chosen known as the "heat island." for investigation because Mitchell (1953) Factors contributing to a heat island's showed that increased human activity existence are integral parts of urban through the week days cause warmer areas - pavement, brick, concrete, as- urban temperatures than those that oc- phalt, and other stone-like building mat- cur on weekends. erials ; high volume of motorized traffic ; large concentrations of heated and RESULTS otherwise energy-serviced buildings ; As may readily be seen (figs. 1 to 4), and industrial complexes. Despite the the center of the heat island in Akron near certainty that a heat island can be formed over the same area on all four identified in almost any urban center, occasions - approximately 1.5 miles the precise location and the magnitude northwest of the central business dis- of its development are anything but cer- trict (CBD). The intensity of the heat tain. The factors bearing on the way in island is indicated by the temperature which heat islands develop are reviewed differential between the edge of the city as the heat island in Akron, Ohio, is and the heat island center. The intensity examined here. varied with the season: g0F in spring, 6OF in summer, 14OF in autumn, and METHOD OF DATA COLLECTION 7°F in winter. Data for this study were collected on The center of Akron's heat island is the nights of 17 April, 11 July, and 10 located over a mixed residential-com- October 1972 and 2 January 1973, using mercial land-use area. The commercial the automobile traverse method similar activity is located in relatively low- to that used by Hutcheon et al. (1967). profile buildings with large paved park- Weather on the days chosen for the in- ing areas. These low-profile buildings vestigation varied significantly enough have very little shadowing effect on each throughout the days (and during the other ; hence considerable solar radiation Figure I .-Akron's heat island location 2200 Figure 3.-Akron's heat island location 2 I00 EST, 1 7 April 1972. EST, 10 October 1972.

Figure 2.-Akron's heat island location 2100 Figure 4.-Akron's heat island location 2200 EST, I I July 1972. EST, 2 January 1973. is absorbed by them during the day. ables are important, since human and After sunset, the stone-like surfaces con- animal metabolic heat, and waste heat duct heat to the urban air-causing ex- from space heating (and cooling), all cess heating. contribute heat to the urban atmosphere. The housing at the center of the heat- In addition, the heat-island center is island area varies from modern multi- located over relatively high ground that storied apartment houses to large frame causes cold air to drain away from that (and a few brick) houses that are about area. The heat-island center is approxi- 60 years old and have been converted mately 100 feet higher than the sur- into apartments. The average number rounding ground. of residents per apartment is three. This concentration of apartments has DISCUSSION resulted in the area having the second Since heat-island formation is due to highest housing and population density the impact of man, it follows that heat in the city of Akron. The areas of the islands can be reduced, intensified, or city that have the highest housing and possibly eliminated by man's effort. In- population density are located on low- vestigation into how to eliminate a heat lying ground, and cold air drainage pre- island should become an area of research vents the formation of a heat island over after its location and intensity is known. these high housing/population density Bach (1972) showed that wise land use areas. can decrease the effect of heat islands. The University of Akron Laboratory Some may question why this type of for Spatial and Cartographic Analysis investigation should become important has produced maps of Akron, using 1970 and a source of intensive investigation. Census Data, which show the sections of The answer is simple - heat islands are the city with population density of 20 to killers. Clarke (1972) and Buechley 25 persons per acre and 6 to 10 houses et nl. (1972) have shown that the com- per acre (figs. 5 and 6). bination of increased heat and humidity These population and housing vari- of urban areas produces thermal stres-

Figure 5.-Housing density in the heat island Figure 6.-Population density in the heat in Akron, Ohio (1970 Census data). island in Akron,- Ohio (1970 Census data). ses, particularly at night among the poor que case. As this study has shown, and elderly, who are the predominate careful and precise measurements need economic and age groups that live in the to be taken within an urban area to de- central cities. termine the nature, extent, and magni- These thermal stresses are a signi- tude of heat islands. ficant factor in causing urban mortality The heat island in Akron is the result rates to be much higher than rural or of the interaction of four variables: suburban mortality rates during heat- elevation, land use, housing density, and wave conditions. The thermal stresses l~opulationdensity. A significant change are produced because there is virtually in any of the four could cause the heat no relief from heat and humidity in the island to be weakened. urban areas at night due to the heat- City planners should take such mat- island effect and the lack of air con- ters as those discussed in this study into ditioning among the poor and elderly. consideration when making plans for However, in the rural and suburban urban expansion or building within the areas, relief from thermal stress occurs city, because whatever they do affects once nocturnal cooling begins. the microclimate. However, it seems Just how significant this death rate that most planners have little knowledge can be was indicated by Bridger and of microclimatology. Unpleasant urban Hefland (1968). They studied the St. climates reflect both the lack of plan- Louis, Missouri, area for July 1966 and ning and the lack of knowledge of found that, although the corporate limits microclimatology. of the city (at that time) contained only 32 percent of the metropolitan popula- LITERATURE CITED tion, 85 percent of the heat-related Bach, W. deaths took place within the corporate 1972. URBAN CLIMATE, AIR POLLUTION AND CLIMATE. In Urbanization and Environment, limits. The urban death rate was 5.5 edited by T. R. Detwyler. Duxbury Press: times as great as the rural death rate Belmont, Calif. P. 69-90. for the same time period. Other studies Bridger, C. A., and L. A. Hefland. 1968. MORTALITYFROM HEAT DURING JULY, have indicated similar results. 1966 IN ILLINOIS.Int. J. Biometeorol. 12: 51-70. Buechley, R. W., J. V. Bruggen, and CONCLUSION L. E. Truppi. 1972. HEATISLANDYDEATH ISLAND? Environ. Despite the prevalence of heat islands Res. 5 :85-72. as urban climatological phenomena, Clarke, J. F. their location, nature, and magnitude 1972. SOMEEFFECTS OF THE URBAN STRUCTURE ON IIEAT MORTALITY. Environ. Res. 5: 93- cannot be inferred on the basis of city 104. Hutcheon, R. J., R. H. Johnson, W. P. Lowry, size, industry mix, and housing density C. H. Black, and D. Hadley. alone. Local climatological and physio- 1967. OBSERVATIONSOF THE URBAN HEAT ISLAND IN A SMALL CITY. Am. Meteorol. Soc. graphic conditions must also be con- Bull. 48 :7-9. sidered. The net result is that, at least Mitchell, J. M., Jr. until much more work is done, each ur- 1953. ON THE CAUSE OF INSTRUMENTALLY OBSERVED SECULAR TEMPERATURE TRENDS. J. ban situation must be treated as a uni- Meteorol. 9 :244-261.