URBAN HEAT ISLAND EFFECT

URBAN HEAT ISLAND EFFECTABIN BABU C7A7103

We hear a lot about global warming right..

Regional climate describes the general climatic conditions of the locality. A microclimate is the climate of a small area that is different from the area around ithumans are changing climatic systems by1.changing land cover2.releasing pollutants3.releasing greenhouse gasesrapid urbanization and industrialization have brought about microclimatic change(thermal structure)URBAN HEAT ISLAND EFFECT

WHAT IS UHI????

CITIES UNDER TREAT OF UHI

NEW YORK CHICAGOLONDON BEIJINGDELHI BENGALURUTRIVANDRUMKOCHI..

DIURNAL BEHAVIOUR

Causes

properties of materialsLack of vegetationUrban canyon effectWaste heatAlbedoThermal plume

1.PROPERTIES OF MATERIALS& ALBEDOCONCRETE ,ASPHALT ABSORB SW RADIATIONS AND RELEASE DURING NIGHTDIFFERENT THERMAL PROPERTIES (HEAT CAPACITY,THERMAL CONDUCTIVITY) SURFACE RADIATIVE PROPERTIES(ALBEDO &EMISSIVITY)WASTE HEATCOLOUR

ROOF SURFACE TEMPERATURE

PAVEMENT REFLECTION

Wind movement

2.LACK OF VEGETATION

Lack of evapotranspirationLoss of shade and cooling effectsIncreases co2 concentrationHigh level of pollution Retaining of pollutants change radiative properties of atmosphere

3.URBAN CANYON EFFECT

similar to a natural canyon.streets cutting through dense blocks of structures.Affects wind movement.Temperature can be elevated Stagnation of air belowMultiple reflection increases temperature

Multiple reflection

IMPACTSIncreasing peak energy demandAir conditioning costsAir pollution and greenhouse gas emissions.Water quality and air quality.Heat-related illness and mortality

Heat related illness

UHI can increase duration of heat waves.heat stroke, heat exhaustion, heat cramps, depression, dementia, Parkinsons disease.Mortality rate hikes.

MITIGATIONReflective surfacesCOOL ROOFSGREEN ROOFSlight-colored concrete & green concretePlanting trees(URBAN REFORESTATION)Green building promotionGovernment initiativespolicies ,measures strategies

White roofs/coolroofs

Green roofs

Light coloured &green concrete

Government initiativespolicies measures strategies

Urban heat island effect in India

UHI effect in Kerala