5.1 Conceptual Frame
The term ‘heat island’ refers to urban air and
surface temperatures that are higher than the
nearby rural areas. Meteorological data measure
the long-term air temperature. Air temperature is
a measure of sensible heat along with other
meteorological variables of humidity, wind
velocity and calm conditions. This study is an
attempt to enquire the growing Urban Heat
Island Intensity in the megacity of Hyderabad. It
is a study on the climatic transition in a major
city of peninsular India. Thermal imageries have
been utilized by some scholars for the study of
Urban Heat Island (UHI), which do not draw a
cumulative temporal perspective. Several studies
on urban heat island have taken up the problem
largely relegated to temperature changes. Urban
heat island is not a cognizable problem of towns
and small cities. It is a matter of great concern for
the million and megacities. The problem of urban
heat island is already critical in the megacities.
Still, however, the megacities are more rapidly
growing in area and population. This is because
the factors of production and relative sustainability are higher only in the large Indian cities.
The study of urban heat island helps to understand the air quality, energy use, water use efficiency and the level of human comfort. As
compared with rural areas, the urban districts
have high heat absorption, low evaporative heat
loss and slow transmission of heat. Heat emitted
in urban districts is much higher than that in rural
areas. The tall buildings within the megacities
provide multiple-tier surfaces for the absorption
of sunlight, increasing the propensity with which
urban areas are heated. Urban micro climates are
complex because of a number of diverse meteorological factors in varying interaction. Solar
radiation and temperature can vary significantly
according to topography and local surroundings.
The annual mean air temperature of a city
with one million or more people can be 1–3 °C
warmer than its surroundings (Oke 1997).
Smithson et al. (2008) find out that the warmth of
concrete and brick on a summer’s evening is due
to the high heat capacity of the built-up surfaces.
Goudie (2006) compared the rural and urban
areas and distinguished that the city surfaces
absorb significantly more solar radiation, because
concrete city surfaces have both great thermal
capacity and conductivity, so that heat is stored
during the day and released by night. Oke (1978)
noted a relationship between heat island intensity
and city size. Nabeshima et al. (2008) brought
out a relationship between rural-urban temperatures. Stone (2006) studied the temperature data
from urban and proximate rural stations for 50
large U.S. metropolitan areas and analyzed the
mean decadal rate of change in urban temperatures and heat island intensity.
5.2 Hyderabad: City Size
and Morphology
Hyderabad is the primate city of the new
Telangana State. Hyderabad is also capital city of
the land-locked Telangana state. The city is
located on the visibly feeble Musi River, which
is the tributary of Krishna—the second largest
river basin of Peninsular India. Hyderabad is
situated at an altitude of 542 metres or 1778 feet
above mean sea level. Figure 5.1 illustrates the
physiographic outlay of Hyderabad along with
the prominent water bodies. This sixteenth century city was founded by Muhammad Quli Qutb
Shah in 1591. The city’s Golconda Fort was
developed to the north of Musi River on the
hillock as has often been the strategic preference
for most of the forts in the world. There are a
number of large water bodies like Hussain Sagar,
Osman Sagar and Himayat Sagar, which have
been built to sustain the city water supply.
5.3 Geographical Personality
and Meteorological Profile
Geographically, Hyderabad is a distinctly
sprawling megacity. The undulating topography
and the resultant water bodies have played a
crucial role in its scattered growth. The megacity
of Hyderabad is thoroughly tropical in its
44
G. Salahuddin
The term ‘heat island’ refers to urban air and
surface temperatures that are higher than the
nearby rural areas. Meteorological data measure
the long-term air temperature. Air temperature is
a measure of sensible heat along with other
meteorological variables of humidity, wind
velocity and calm conditions. This study is an
attempt to enquire the growing Urban Heat
Island Intensity in the megacity of Hyderabad. It
is a study on the climatic transition in a major
city of peninsular India. Thermal imageries have
been utilized by some scholars for the study of
Urban Heat Island (UHI), which do not draw a
cumulative temporal perspective. Several studies
on urban heat island have taken up the problem
largely relegated to temperature changes. Urban
heat island is not a cognizable problem of towns
and small cities. It is a matter of great concern for
the million and megacities. The problem of urban
heat island is already critical in the megacities.
Still, however, the megacities are more rapidly
growing in area and population. This is because
the factors of production and relative sustainability are higher only in the large Indian cities.
The study of urban heat island helps to understand the air quality, energy use, water use efficiency and the level of human comfort. As
compared with rural areas, the urban districts
have high heat absorption, low evaporative heat
loss and slow transmission of heat. Heat emitted
in urban districts is much higher than that in rural
areas. The tall buildings within the megacities
provide multiple-tier surfaces for the absorption
of sunlight, increasing the propensity with which
urban areas are heated. Urban micro climates are
complex because of a number of diverse meteorological factors in varying interaction. Solar
radiation and temperature can vary significantly
according to topography and local surroundings.
The annual mean air temperature of a city
with one million or more people can be 1–3 °C
warmer than its surroundings (Oke 1997).
Smithson et al. (2008) find out that the warmth of
concrete and brick on a summer’s evening is due
to the high heat capacity of the built-up surfaces.
Goudie (2006) compared the rural and urban
areas and distinguished that the city surfaces
absorb significantly more solar radiation, because
concrete city surfaces have both great thermal
capacity and conductivity, so that heat is stored
during the day and released by night. Oke (1978)
noted a relationship between heat island intensity
and city size. Nabeshima et al. (2008) brought
out a relationship between rural-urban temperatures. Stone (2006) studied the temperature data
from urban and proximate rural stations for 50
large U.S. metropolitan areas and analyzed the
mean decadal rate of change in urban temperatures and heat island intensity.
5.2 Hyderabad: City Size
and Morphology
Hyderabad is the primate city of the new
Telangana State. Hyderabad is also capital city of
the land-locked Telangana state. The city is
located on the visibly feeble Musi River, which
is the tributary of Krishna—the second largest
river basin of Peninsular India. Hyderabad is
situated at an altitude of 542 metres or 1778 feet
above mean sea level. Figure 5.1 illustrates the
physiographic outlay of Hyderabad along with
the prominent water bodies. This sixteenth century city was founded by Muhammad Quli Qutb
Shah in 1591. The city’s Golconda Fort was
developed to the north of Musi River on the
hillock as has often been the strategic preference
for most of the forts in the world. There are a
number of large water bodies like Hussain Sagar,
Osman Sagar and Himayat Sagar, which have
been built to sustain the city water supply.
5.3 Geographical Personality
and Meteorological Profile
Geographically, Hyderabad is a distinctly
sprawling megacity. The undulating topography
and the resultant water bodies have played a
crucial role in its scattered growth. The megacity
of Hyderabad is thoroughly tropical in its
44
G. Salahuddin