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Increased urban land use and occupation alters the local thermal field resulting in the development of warmer regions known as urban heat islands (UHIs). [8] An urban heat island is a phenomenon where these surface temperature deviations and air in the lowest levels of the atmosphere are concentrated in urban areas and those immediately ...
A definition of urban heat island is: "The relative warmth of a city compared with surrounding rural areas." [14]: 2926 This relative warmth is caused by "heat trapping due to land use, the configuration and design of the built environment, including street layout and building size, the heat-absorbing properties of urban building materials, reduced ventilation, reduced greenery and water ...
The urban environment has two atmosphere layers, besides the planetary boundary layer (PBL) outside and extending well above the city: (1) The urban boundary layer is due to the spatially integrated heat and moisture exchanges between the city and its overlying air. (2) The surface of the city corresponds to the level of the urban canopy layer.
The urban heat island is a phenomenon in which central regions of urban centers exhibit higher mean temperatures than surrounding urban areas. [39] Much of this effect can be attributed to low city albedo , the reflecting power of a surface, and the increased surface area of buildings to absorb solar radiation. [ 21 ]
Despite being a water-rich zone, climate projection models suggest that by 2050, between 52 and 146 million people living in South Asia could face increased water scarcity due to climate change, accounting for 18% of the global population exposed to water scarcity. [63] Urban water access is particularly critical in South Asia as it remains ...
As storm water passes over hot rooftops, parking lots, roads and sidewalks it absorbs some of the heat, an effect of the urban heat island. Storm water management facilities that absorb runoff or direct it into groundwater, such as bioretention systems and infiltration basins, reduce these thermal effects by allowing the water more time to ...
The use of impervious dark surfaces which retain and reflect heat, and human generated heat energy lead to an urban heat island in the center of cities, where the temperature is increased significantly. A large urban microclimate does not only affect temperature, but also rainfall, snowfall, air pressure and wind, the concentration of polluted ...
Types of nonpoint source water pollution include sediment, nutrients, toxic contaminants and chemicals and pathogens. Principal sources of nonpoint source water pollution include: urban and suburban areas, agricultural operations, atmospheric inputs, highway runoff, forestry and mining operations, marinas and boating activities.