What is urban heat island intensity?

The intensity of the heat island is the simplest and most quantitative indicator of the thermal modification imposed by the city upon the territory in which it is situated and of its relative warming in relation to the surrounding rural environment at night time (Kim and Baik, 2002; Memon et al., 2009).Jun 2, 2015

What is urban heat intensity?

The dependent variable for the analysis is urban heat island intensity (UHI). The UHI is defined as the air temperature difference between a location within the city and a reference rural location at a specific time.

What is meant by urban heat island?

An urban heat island occurs when a city experiences much warmer temperatures than nearby rural areas. The difference in temperature between urban and less-developed rural areas has to do with how well the surfaces in each environment absorb and hold heat.

How much hotter is an urban heat island?

A review of research studies and data found that in the United States, the heat island effect results in daytime temperatures in urban areas about 1–7°F higher than temperatures in outlying areas and nighttime temperatures about 2–5°F higher.

What is the urban heat island and when is it strongest?

The urban heat island effect is strongest at night, when the daytime had significant direct heating of the surface (e.g. clear sky conditions), and when the atmospheric boundary layer temperature inversion is close enough to the ground to prevent ventilation / mixing with the air above.

What is urban island?

"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.

How do you identify an urban heat island?

What is an urban heat island? An urban heat island is a metropolitan area which is significantly warmer than its surrounding rural areas. The temperature difference is usually larger at night than during the day, and is most obvious when winds are weak.

What causes urban heat island?

How Do Heat Islands Form? Heat islands form as vegetation is replaced by asphalt and concrete for roads, buildings, and other structures necessary to accommodate growing populations. These surfaces absorb—rather than reflect—the sun's heat, causing surface temperatures and overall ambient temperatures to rise.

Why is urban heat island a problem?

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.

How does urban heat island effect the climate?

It found that local warming, caused by the urban heat island effect, “significantly increases temperatures as well as economic losses in addition to global warming.” In fact, the study estimated that the added effects of urban heat island warming could double the economic losses expected from human-caused climate …