urban microclimate study in a coastal city in south india

1. Urban Microclimate Study in a Coastal City in
South India
Jan Jose
II MSc Physics
Catholicate College
Pathanamthitta , India
Supervising Guide
Dr. George Thomas
Department of Physics
Catholicate College
Pathanamthitta

2. WHAT IS URBAN HEAT ISLAND EFFECT ?
An Urban Heat Island (UHI) is the phenomenon of elevated air
temperature within the urban area with respect to adjoining rural
areas.

3. Heat Island types
 Surface urban heat island: exists at the surface and is remotely sensed.
 Subsurface heat island : beneath the city surface
 Atmospheric heat island
3
Boundary layer urban
heat islands: start from
the rooftop and treetop
level and extend up to the
point where urban
landscapes no longer
influence the atmosphere
Canopy layer urban
heat islands: exist in the
layer of air where people
live, from the ground to
blow the tops of trees and
roofs

4. Factors which influence Urban Heat
Island
 Lack of Vegetation
 Thermal Property of Building Material
 Humidity
 Soil Moisture
 Street Geometry
 Coverage Area
 Energy Consumption
 Pollution
 Anthropogenic Heat Generation

5. Aim of the study
• To investigate the development of the Urban Heat Island
in a tropical coastal city (KOCHI)
• To understand the Urban Heat Island effect based on land
cover changes associated with urbanization

6. 6
Urban sprawl pattern of Kochi
1967 1990
2011
Source: NCESS Annual Report ,
2013

7. STUDY AREA …Methodology
KOCHI,ERNAKULAM

8. Mobile Traverse set-up
Steveson’s screen
Fixed Station set-up
Humidity and temperature sensor
8
METHODOLOGY

9. …….. METHODOLOGY
 Mobile surveys were carried out during winter (Jan – Feb)
in 2019 and 2020 and summer (Mar – Apr) in 2019 to
quantify UHI intensity in Kochi
 Mobile traverses were carried out in the evening from
07:30 pm to 10:30 pm and during pre-dawn period from
04:00 am to 06:00 am
 The reference temperature was taken from a temperature
recorder installed at a rural region in the study area
 The instantaneous temperature differences between all
observational points and the reference site were calculated
in order to determine UHI intensity

10. RESULTS
Sl.
No.
Time Date Temperature (ᵒC) Peak UHI
intensity (ᵒC)
City Centre Reference
(Summer Season)
S1 Predawn 17.04.2019 29.8 25.5 4.3
S2 Late evening 16.04.2019 32.3 29.0 3.3
(Winter Season)
S3 Predawn 27.01.2019 27.3 22.0 5.3
S4 Predawn 01.02.2020 27.1 23.5 3.4
S5 Late evening 26.01.2019 28.5 25.2 3.3
S6 Late evening 31.01.2020 29.8 27.0 2.8

11. Spatial variation of UHI intensity in Summer 2019
Predawn Late evening
....Results

12. ....Results
Spatial variation of UHI intensity in Winter 2019
Predawn Late evening

13. Spatial variation of UHI intensity in Winter 2020
Predawn Late evening
....Results

14. Temperature v/s Time
T(Urban) – T(Reference) v/s Time
Cooling rate during winter 2020 ....Results

15. CONCLUSIONS
 Highest observed urban heat island intensities in Kochi
during this study were 5.3 oC and 3.4 oC during winter
morning in 2019 and 2020
 Highest observed UHI during winter evening in same
period were 3.3 oC and 2.8 oC
 Highest observed UHI during summer morning and
evening were 4.3 oC and 3.3 oC
 The average cooling rate during night at city centre was
0.24 oC/hr and reference zone was 0.50 oC/hr

16. ………..CONCLUSIONS
 Proper planning of the built environment and selection
of raw materials is necessary to reduce the problem of
excessive nocturnal heat loads within the built
environment