The tall buildings within many urban areas provide multiple surfaces for the reflection and absorption of sunlight, increasing the efficiency with which urban areas are heated. This is called the "urban canyon effect".
What causes the urban island effect?
The main causes are changes in the land surface by urban development along with waste heat generated by energy use. As population centers grow, they tend to change greater areas of land which then undergo a corresponding increase in average temperature.
Can you explain the urban heat island effect?
"Urban heat islands" occur when cities replace natural land cover with dense concentrations of pavement, buildings, and other surfaces that absorb and retain heat. This effect increases energy costs (e.g., for air conditioning), air pollution levels, and heat-related illness and mortality.
What is the meaning of urban climate?
urban climate, any set of climatic conditions that prevails in a large metropolitan area and that differs from the climate of its rural surroundings.
What is an urban heat island and what causes it?
Heat islands form as a result of several factors: Reduced Natural Landscapes in Urban Areas. Trees, vegetation, and water bodies tend to cool the air by providing shade, transpiring water from plant leaves, and evaporating surface water, respectively.
What are the 4 major impacts of urban heat islands?
Heat islands contribute to higher daytime temperatures, reduced nighttime cooling, and higher air-pollution levels. These, in turn, contribute to heat-related deaths and heat-related illnesses such as general discomfort, respiratory difficulties, heat cramps, heat exhaustion, and non-fatal heat stroke.
What is the effect of cities on rainfall?
The urban heat island effect not only makes cities considerably warmer than the areas that surround them, this higher temperature also causes cities to have greater cloud cover and higher amounts and more intense periods of rainfall found over and downwind of the urban areas.
What is the urban heat island effect according to NASA?
The urban heat island effect occurs primarily during the day when urban impervious surfaces absorb more solar radiation than the surrounding vegetated areas, resulting in a few degrees temperature difference. The urban area has also lost the trees and vegetation that naturally cool the air.
How do urban areas affect wind?
Winds in an urban microclimates are affected by it surroundings. The general pattern is that winds decrease in urban areas than in suburbs or rural areas. The speed of winds is lower in altitudes in built up areas are slower because winds are deflected over high buildings.
How does urban areas affect climate?
At the same time, cities are a key contributor to climate change, as urban activities are major sources of greenhouse gas emissions. Estimates suggest that cities are responsible for 75 percent of global CO2 emissions, with transport and buildings being among the largest contributors.