Urban Form and Urban Materials as Controller of Urban Climate in Valparaiso, Chile

The urban heat island (UHI) effect on the city and urban climate are related whit urban form and urban materials: it's an evidence of human influence in climate change. Into the cities, the air temperature increases in downtown and go to outskirts decreases. Valparaíso, Chile, is located in a Mediterranean climate in the southern hemisphere (-33°03'). The urban area of the city is 400 km2 and its population reaches 300,000 inhabitants. The behaviour of air temperature in the city in winter and summer and on sunny days and cloudy days has been recorded. In all days heat island phenomenon is registered. A greater increase of UHI in summer and in sunny day has been recorded. The variation of the temperatures of the materials that make up the urban canyons has also been recorded, presenting different dispersions and variation according to whether it is a sunny day or a cloudy day. In sunny day all day a large dispersion is registered, at afternoon spatially. An important factor in the behaviour of the street climate is its morphology. This condition has been recorded with the visible sky factor (SVF) and with the geographic orientation of the studied canyons. Both the global urban form, the visibility of the sky, the street morphology and the materials of the city affect the urban air temperature variations. City normative planning and designers should consider these variables and its influences.