Climate presentation on Warm and Humid Zone

1. PRESENTED BY:
RAKHI DEV
RASHMI R
VENKATESH
SUNIDHI MADHAV
SWATHE SIVAGAMI. Y
SOUMYA NAYAK
SONALI
III SEM C-Section

3. CLIMATIC
ZONES OF
INDIA:
Hot and Dry
Warm and
Humid
Composite
Temperate
Cold

4. 3 Main Cities
with WARM
AND HUMID
CLIMATE:
Chennai
Kolkata
Mumbai
NOTE : All
the 3 cities
are coastal
areas

5. CHENNAI
 Chennai has a tropical wet and dry climate (Köppen:Aw). The
city lies on the thermal equator and is also on the coast, which
prevents extreme variation in seasonal temperature. The hottest
part of the year is late May to early June, known regionally
as Agni Nakshatram ("fire star") or as Kathiri Veyyil, with
maximum temperatures around 35–40 °
 The thermal equator (also known as "the heat equator") is a
belt encircling the Earth, defined by the set of locations having
the highest mean annual temperature at each longitude around
the globe.
 The city gets most of its seasonal rainfall from the north–
east monsoon winds, from mid–October to mid–
December. Cyclones in the Bay of Bengal sometimes hit the city.
 Prevailing winds in Chennai are usually southwesterly between
April and October[ and northeasterly during the rest of the year.

6. Temperature
Over the course of a year, the temperature typically varies
from 21°C to 38°C and is rarely below20°C or above 41°C.
Daily High and Low Temperature:
The daily average low (blue) and high (red) temperature with percentile bands
(inner band from 25th to 75th percentile, outer band from 10th to 90th percentile).

7. Fraction of Time Spent in Various
Temperature Bands
The average fraction of time spent in various temperature bands: frigid
(below -9°C), freezing (-9°C to 0°C), cold (0°C to 10°C), cool (10°C to 18°C),
comfortable (18°C to 24°C), warm (24°C to 29°C), hot (29°C to 38°C) and
sweltering (above 38°C).

8. Daily Hours of Daylight and Twilight
The number of hours during which the Sun is visible (black line), with
various degrees of daylight, twilight, and night, indicated by the color
bands. From bottom (most yellow) to top (most gray

9. Daily Sunrise & Sunset with Twilight
The solar day over the course of the year 2012 . From bottom to top, the black lines
are the previous solar midnight, sunrise, solar noon, sunset, and the next solar
midnight. The day, twilights (solar, civil, nautical, and astronomical), and night are
indicated by the color bands from yellow to gray.

10. CLOUDS
The median cloud cover ranges from 38% (mostly clear) to 79% (partly cloudy). The sky is
cloudiest on July 26 and clearest on February 29. The clearer part of the year begins
around December 4. The cloudier part of the year begins around May 31.
MEDIAN CLOUD COVER The median daily cloud cover (black line) with
percentile bands (inner band from 40th to 60th percentile, outer band from
25% -75%).

11. CLOUD COVER TYPES
The fraction of time spent in each of the five sky cover categories. From top
(most blue) to bottom (most gray), the categories are clear, mostly clear, partly
cloudy, mostly cloudy, and overcast. Pink indicates missing data. Outside of the
United States clear skies are often reported ambiguously, leading them to be
lumped in with the missing data.

12. PROBABILITY OF PRECIPITATION AT
SOME POINT IN THE DAY
The fraction of days in which various types of precipitation are
observed. If more than one type of precipitation is reported in a given
day, the more severe precipitation is counted. The order of severity is
from the top down in this graph, with the most severe at the bottom.

13. PRECIPITATION
 The most common forms of precipitation are thunderstorms,
drizzle, moderate rain, and light rain.
 Thunderstorms are the most severe precipitation observed
during 32% of those days with precipitation. They are most likely
around October 8, when it is observed during 23% of all days.
 Drizzle is the most severe precipitation observed during 29% of those
days with precipitation. It is most likely around July 28, when it is
observed during 19% of all days.
 Moderate rain is the most severe precipitation observed during 21% of
those days with precipitation. It is most likely around November 21,
when it is observed during 15% of all days.
 Light rain is the most severe precipitation observed during 16% of
those days with precipitation. It is most likely around July 21, when it is
observed during 10% of all days.
 snow is exceptionally unlikely to fall at any time during the year at this
location or this station does not reliably report precipitation types.

15. Warm Season Precipitation
During the warm season, which lasts
from April 30 to June 18, there is
a 25% average chance that precipitation will
be observed at some point during a given
day. When precipitation does occur it is
most often in the form of thunderstorms
(38% of days with precipitation have at
worst thunderstorms), drizzle (31%),
moderate rain (16%), and light rain (14%).
Cold Season Precipitation
During the cold season, which lasts
from October 26 to February 9, there is
a 31% average chance that precipitation will
be observed at some point during a given
day. When precipitation does occur it is
most often in the form of moderate rain
(29% of days with precipitation have at
worst moderate rain), drizzle (27%),
thunderstorms (24%), and light rain (17%).

16. HUMIDITY
 The relative humidity typically ranges
from 39% (comfortable) to 95% (very humid) over the
course of the year, rarely dropping below 28% (dry)
and reaching as high as 100% (very humid).
 The air is driest around May 23, at which time the
relative humidity drops below 45% (comfortable)
three days out of four; it is most
humid around October 30, exceeding 94% (very
humid) three days out of four.

17. RELATIVE HUMIDITY
The average daily high (blue) and low (brown) relative humidity with
percentile bands (inner bands from 25th to 75th percentile, outer bands from
10th to 90th percentile).

18. DEW POINT
 Dew point is often a better measure of how
comfortable a person will find the weather than
relative humidity because it more directly relates to
whether perspiration will evaporate from the skin,
thereby cooling the body. Lower dew points feel drier
and higher dew points feel more humid.
 Over the course of a year, the dew point typically varies
from 18°C (mildy humid) to 27°C (very oppressive) and
is rarely below 14°C (comfortable) or above 28°C (very
oppressive).

19. The daily average low (blue) and high (red) dew point with percentile
bands (inner band from 25th to 75th percentile, outer band from 10th
to 90th percentile).

20. WIND
 Over the course of the year typical wind speeds vary
from 0 m/s to 7 m/s (calm to moderate breeze), rarely
exceeding 9 m/s (fresh breeze).
 The highest average wind speed of 4 m/s (gentle
breeze) occurs around May 27, at which time the
average daily maximum wind speed is 7 m/s (moderate
breeze).
 The lowest average wind speed of 2 m/s (light breeze)
occurs around October 30, at which time the average
daily maximum wind speed is 5 m/s (gentle breeze).

21. WIND SPEED
The average daily minimum (red), maximum (green), and average (black) wind
speed with percentile bands (inner band from 25th to 75th percentile, outer band
from 10th to 90th percentile).
The wind is most often out of the south (11% of the time) and west (10% of the
time). The wind is least often out of the north west (3% of the time) and north
(4% of the time).

22. WIND DIRECTIONS OVER THE ENTIRE YEAR
The fraction of time spent with the wind blowing from the various
directions over the entire year. Values do not sum to 100% because the
wind direction is undefined when the wind speed is zero.

23. Fraction of Time Spent with Various Wind
Directions
The fraction of time spent with the wind blowing from the various
directions on a daily basis. Stacked values do not always sum to 100%
because the wind direction is undefined when the wind speed is zero.

24. GEOLOGY
 The geology of Chennai comprises
mostly clay, shale and sandstone. The city is classified
into three regions based on geology, sandy areas,
clayey areas and hard-rock areas. Sandy areas are
found along the river banks and the coasts. Clayey
regions cover most of the city.
 In sandy areas such as and the rest of coastal Chennai,
rainwater run-off percolates very quickly. In clayey and
hard rock areas, rainwater percolates slowly, but it is
held by the soil for a longer time.

25. MUMBAI
 Mumbai receives pretty heavy
rainfall through the Southwest
Monsoon winds, which start
in mid June.
 The rainfall quells the heat a
little.
 The average temperature falls
from 30 to 25 over the next three
months. The rainfall lasts till
September.
 With a brief stint of heat in
October, the 'on paper' winter
starts in November. Thus the
temperatures in Mumbai are
comparatively bearable from
June to December.
 Chennai receives rainfall
(much lower than Mumbai)
predominantly through the
North East Monsoon winds
which start only in mid
September and last till
December.
 This makes the months of June,
July and August as unbearable as
summer in terms of
temperature.
 This quarter of the year is what
differentiates the climate of the
two cities.
CHENNAI

26. SOUTHWEST MONSOON The southwestern summer
monsoons occur from July
through September.
This causes a low pressure
area over the northern and
central Indian subcontinent. To
fill this void, the moisture-laden
winds from the Indian
Ocean rush in to the
subcontinent.
These winds, rich in moisture,
are drawn towards
the Himalayas.
The Himalayas act like a high
wall, blocking the winds from
passing into Central Asia, and
forcing them to rise.
 As the clouds rise
their temperature drops and
precipitation occurs.

27.  The southwest monsoon is generally expected to begin
around the beginning of June and fade away by the end of
September. The moisture-laden winds on reaching the
southernmost point of the Indian Peninsula, due to its
topography, become divided into two parts: theArabian
Sea Branch and the Bay of Bengal Branch.
 The Arabian Sea Branch of the Southwest Monsoon first
hits the Western Ghats of the coastal state of Kerala, India,
thus making this area the first state in India to receive rain
from the Southwest Monsoon.
 The Bay of Bengal Branch of Southwest Monsoon flows
over the Bay of Bengal heading towards North-East
India and Bengal, picking up more moisture from the Bay
of Bengal.
 Certain regions of India like Assam and West Bengal, also
frequently experience heavy floods during this season

28. NORTHEAST MONSOON  Around September, with
the sun fast retreating
south, the northern land
mass of the Indian
subcontinent begins to
cool off rapidly.
 With this air pressure
begins to build over
northern India,
the Indian Ocean and its
surrounding atmosphere
still holds its heat.
 This causes cold wind to
sweep down from
the Himalayas and Indo-
Gangetic Plain towards
the vast spans of the
Indian Ocean south of
the Deccan peninsula.
This is known as the
Northeast Monsoon or
Retreating Monsoon.

29.  While travelling towards the Indian Ocean, the dry cold wind
picks up some moisture from the Bay of Bengal and pours it over
peninsularIndiaand parts of Sri Lanka.
 Cities like Chennai, which get less rain from the Southwest
Monsoon, receives rain from this Monsoon. About 50% to
60% of the rain received by the state of Tamil Nadu is from
the Northeast Monsoon.
 In Southern Asia, the northeastern monsoons take place from
December to early March when the surface high-pressure system
is strongest.
 The jet stream in this region splits into the southern subtropical
jet and the polar jet. The subtropical flow directs northeasterly
winds to blow across southern Asia, creating dry air
streams which produce clear skies over India.
 Meanwhile, a low pressure system develops over South-East
Asia and Australia and winds are directed toward Australia
known as a monsoon trough.

30. DESIGN FOR WARM AND HUMID
ZONES
 • Provide maximum ventilation and free air movement
by large openings.
• Provide maximum shading of direct and diffuse solar
radiation.
• Avoid heat storage.
• Use reflective outer surfaces.
• Use ventilated double roofs.
• Use vegetation to moderate the solar impact.

31.  SUN ORIENTATION
Settlements should be placed preferably on southern
or northern slopes, ideally facing away from the
equator. The warm-humid climate zones are
generally located near the equator. As a consequence,
east and west slopes receive more radiation compared
to north and south slopes and are, therefore,
disadvantageous.
 WIND ORIENTATION
Ideal sites are windward slopes near the crest or near
the beach, where regular winds exist. The ventilation
effect of winds can be improved by effective
arrangement of vegetation. open settlement pattern is
the appropriate response to the climate.

32.  To provide sufficient air circulation, buildings should be
scattered
 Buildings should be separated with large, free spaces between
them. This allows airflow which provides ventilation for cooling
and a hygienic environment.
 On the other hand, the walking distance to public spaces should
be minimal and the footpaths shaded.
 Groups of buildings should not be built in too compact a
manner. Extended settlements, arranged in a line across the
prevailing wind direction give low resistance to air movement
and are, therefore, the ideal solution.
 In cases where settlements consist of several rows of buildings,
the houses should be staggered to avoid windshaded buildings in
the downwind rows.
 Certain species of trees (e.g. rain trees) form an extraordinary
outdoor space by creating a canopy effect. They should not be
planted too far from each other, so that the crowns form a wide
hall-like space, creating a comfortable microclimate.

33. VENTILATED DOUBLE ROOF