Effects of urban green areas on air temperature in a medium-sized Argentinian city

Urban climate is the result of both atmospheric and geographic factors affecting a region, as well as the morphology, structures and human activities in a city. Urban vegetation in particular affects this climate at a local scale and provides many other social, economic and ecological benefits. Thus, it is important to explore the effects of different green areas used for urban and periurban agriculture and forestry activities (UPAF) on daily atmospheric temperature and the required degrees of cooling or refrigerating temperature. Comfort temperatures were defined using a range 18-24 degrees C and analyzed using actual measured as well as forecasted temperatures using a future scenario. Actual temperatures were recorded from September 2013 to August 2014 using digital sensors across eight sites in Rosario, Argentina: three in the central core with no vegetation, one in the central core with street trees, one in an urban agriculture site, one in a public park and two in periurban agricultural areas. Results show that air temperature in the central core with no vegetation were higher than those in other sites with vegetation during day and night, with the exception of the temperatures measured at the central core site with street trees. Findings also show that temperature effects in urban agricultural gardens of approximately 0.2 ha were similar to those of gardens and public parks 2-3 ha in size. Three UPAF types were classified according to cooling degree days, which decreased in order from (1) central core with no trees; (2) central core with street trees and public parks; and (3) urban and periurban agriculture areas. Conversely, the opposite trends for heating degree days were found. Results from this study can be used for integrating UPAF measures into climate change mitigation and urban planning policies in medium-sized cities in the developing world.