That means more houses, buildings, roads, and parking lots. Satellite images of Atlanta readily show how urban sprawl has pushed into what had been farmland and woodlands, largely along interstate and other major highways. Heat islands are caused by heat buildup during the day in buildings, pavement, and other urban surfaces. This heat is released after sunset and forms a dome of higher temperatures over the city. But Quattrochi and co-investigator Jeffrey Luvall, also at GHCC, have found some hope in the midst of the sweltering cities.
Trees can help reduce temperatures.
That's part of what they want to define and study in Atlanta. By contrast, wooded areas, even small trees islands in the parking lot, show as cool spots. The difference has to do with how materials absorb and release heat. Asphalt absorbs heat from the sun and quickly releases it as heat radiation. Even grassy areas near the woods appear hotter than the woods because a meadow has less vegetation and shade.