UHI is a greater threat generated due to overcrowding and uunsustainable construction practices

1. URBAN HEAT ISLAND EFFECT
ABIN BABU
C7A
7103

2. We hear a lot about global warming
right…..

3. 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 it
humans are changing climatic systems by
1.changing land cover
2.releasing pollutants
3.releasing greenhouse gases
rapid urbanization and industrialization have
brought about microclimatic change(thermal
structure) URBAN HEAT ISLAND EFFECT

4. WHAT IS UHI????

5. CITIES UNDER TREAT OF UHI

6. DIURNAL BEHAVIOUR

7. Causes

8. 1.PROPERTIES OF MATERIALS& ALBEDO
 CONCRETE ,ASPHALT ABSORB SW
RADIATIONS AND RELEASE DURING NIGHT
 DIFFERENT THERMAL PROPERTIES
(HEAT CAPACITY,THERMAL CONDUCTIVITY)
 SURFACE RADIATIVE PROPERTIES(ALBEDO
&EMISSIVITY)
 WASTE HEAT
 COLOUR

10. ROOF SURFACE TEMPERATURE

11. PAVEMENT REFLECTION

13. Wind movement

14. 2.LACK OF VEGETATION

15.  Lack of
evapotranspiration
 Loss of shade and
cooling effects
 Increases co2
concentration
 High level of
pollution
 Retaining of
pollutants change
radiative properties
of atmosphere

17. 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 below
 Multiple reflection increases
temperature

18. Multiple reflection

19.  Increasing peak energy demand
 Air conditioning costs
 Air pollution and greenhouse gas emissions.
 Water quality and air quality.
 Heat-related illness and mortality

20.  UHI can increase
duration of heat waves.
 heat stroke, heat
exhaustion, heat cramps,
depression, dementia,
Parkinson’s disease.
 Mortality rate hikes.

21.  Reflective surfaces
 COOL ROOFS
 GREEN ROOFS
 light-colored concrete & green concrete
 Planting trees(URBAN REFORESTATION)
 Green building promotion
 Government initiatives
 policies ,
 measures
 strategies

27. Government initiatives
 policies
 measures
 strategies

28. Urban heat island effect in India

29. UHI effect in Kerala