Lecture5_GEOG1400

Near the surface surface temperatures can get extreme

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Unformatted text preview: e th balance between the energy flow that it receives and the energy flow that it loses. Near the and the energy flow that it loses. Near the surface, surface, temperatures can get extreme - thin land surface layer warms faster than deep water Specific Specific heat (water > land) water requires more energy to increase its temperature) Mixing Mixing (water better than land)-waves, currents land)Evaporation Evaporation (water cooled easily by evaporation), evaporation evaporation consumes energy Surface energy balance for typical day and night conditions Urban Urban and rural temperature contrasts contrasts Cities: – vegetation is removed, soils are paved – rainwater goes into sewer systems – impervious surfaces are dry, insolation warms the area and evaporation only occurs in patches of grass and trees. – Asphalt, concrete, stone absorb and hold heat and release at night heat and release at night – heat absorption is enhanced by many vertical surfaces – CITIES ARE WARMER THAN RURAL AREAS Urban Heat Islands Urban Heat Islands Air Air temperature in the central region the of a city are typically several typically several degrees degrees warmer than than those of the surrounding suburbs suburbs and countryside. FIGURE 19.5 Urban heat island of Montreal Temperature Contrasts Temperature Contrasts Rural areas: Rural areas: – land surface covered with vegetationvegetationtranspiration (cooling effect) – forests are very cool, shady, radiation is shady, reduced too – soil surfaces are moist, have infiltration of soil water water – when sunlight reaches the soil surface, the when sunlight reaches the soil surface the water water evaporates, thus removing heat and keeping the...
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This document was uploaded on 04/11/2014.

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