1.
ENVIRONMENTAL SCIENCE I
ELEMENTS OF
CLIMATE
BALKHIZ ISMAIL . FSPU, UiTM SARAWAK

2.
♦ The weather elements are used to describe climate
and also to determine the type of climate for a
region.
♦ Three most significant climate elements used to
determine climate are temperature(1)
, precipitation(2)
and wind(3)
.
♦ The other parameters are humidity(4)
, vapor
pressure(5)
, vegetation(6)
, solar radiation(7)
and sky
condition(8)
.
Introduction

3.
1. Temperature
• Measured in degree Celsius
(ºC) with a mercury
thermometer.
• The dry-bulb te m pe rature or
‘True Air Te m pe rature ’
– value taken in the shade
– thermometer being mounted
inside a louvered wooden box –
Stevenson Screen at a height
of 1.2 to 1.8m
– place at open area or space

4.
1. Temperature (cont’d)
STEVENSON SCREEN
Louvered Wooden
Box
1.20 m to 1.80 meter
high from ground

5.
1. Temperature (cont’d)

6.
2. Humidity
 Defined as the mass of water vapor present in unit
volume of air or space and is expressed in g/kg or
g/m3
1. Absolute Humidity (AH)
The actual amount of moisture present in unit mass
of air
2. Saturation-point Humidity (SH)
The amount of moisture the air can hold
3. Relative Humidity (RH)
The ratio of the actual amount of moisture present
to the amount of moisture the air could hold at the
given temperature
RH = AH/SH x 100%

7.
2. Humidity (cont’d)
• Measured with wet and dry-bulb hygrometer
• Hygrometer consists of 2 ordinary mercury
thermometer mounted side by side
• The first one measured the air (dry-bulb)
temperature (DBT) and the other one is
covered with a gauze or wick and is kept
wet which measures the wet-bulb
temperature (WBT)

8.
Dry and wet bulb hygrometer
Whirling sling
hygrometer

9.
3. Precipitation
• the collective term used for rain, snow, hail, dew
and frost – all forms of water deposited from the
atmosphere
• measured by rain gauges and expressed in
millimeters per time unit = mm/month, mm/day

10.
Rain gauges
3. Precipitation (cont’d)

11.
• Convectional rain
- results from the heating of the earth’s surface that
causes air to rise rapidly
- as the air rises, it cools and moisture condenses
into clouds and precipitation
3. Precipitation (cont’d)

12.
• Orographic rain
- results when warm moist air of the ocean is forced
to rise by large mountains
- as the air rises it cools, moisture in the air
condenses and clouds and precipitation result on
the windward side of the mountain while the
leeward side receives very little
- common in British Columbia
3. Precipitation (cont’d)

13.
4. Vapor pressure
• the partial pressure of water present in the air
• varies in different places from time to time
• temperatures gives the main influence to vapour
pressure
• measured in the standard SI pressure unit, N/m2
or
milibar (mb)
• measured with Barometer

14.
5. Wind / Air movement
• resulting from the differences of two vapour
pressures
• there are three global belts of winds in each
hemisphere : trade winds, westerlies and polar
winds
• there are wind systems known as the monsoons
which are the result of annual differences in heating
of land and sea areas

15.
6. Vegetation
• can influence the local or site climate
• it is an important element in the design of outdoor
spaces, providing sun shading and protection from
glare
• their shape and color, also their preferred
orientation and situation will give the influence to
the climate

16.
7. Solar radiation
• an electromagnetic radiation emitted from the sun
• the solar spectrum is broadly divided into three
regions : ultra violet (uv), visible light and infra red
(ir)
• the solar energy at upper limit of the atmosphere
varies from 1.8 – 2.0 cal/cm2
/min according to the
earth’s distance from the sun and the solar activity
• selectively absorbed in the atmosphere according
to the wavelength

17.
7. Solar radiation (cont’d)

18.
8. Sky condition
• usually described in terms of presence or absence
of clouds
• the sky conditions between morning and afternoon
are different and this will affect the design of roofs,
overhangs and shading devices
• sky luminance values are needed if daylighting in
buildings is to be predicted

19.
8. Sky condition (cont’d)
Cloud
• can be differentiate by its shape and height
• can be divided into 3 categories :
i) Low cloud – ground level to 6000 feet, made of
water drops, name start with cumulo
ii) High cloud – 20000 to and above, made of ice
crystal, name start with cirro or cirrus
iii) Intermediate cloud – 6000 to 20000 feet, made
of water drops and ice crystal, name start with alto

20.
8. Sky condition (cont’d)

21.
A LOCAL FACTORS IN
PLANNING &
DESIGNING
BALKHIZ ISMAIL . FSPU, UiTM SARAWAK

22.
Factors in Planning & Designing
A study of local climate is needed in planning &
design. The factors to be considered are :
1. Wind Directions
2. Selection of Materials
3. Radiation (direction of sun)
4. Condition of surrounding
5. Precipitation
6. Airmovement

23.
Factors in Planning & Designing
i) Wind Direction
~ Should be recognize to make sure other building
are not obstructed.
A good of building
arrangement
Poor of building
arrangement

24.
i) Wind Direction(cont’d)
~ It is also influenced by the roof shape of the building.
Wind
direction
Flat roof
Wind direction
Pitch roof
Factors in Planning & Designing

25.
ii) Selection of building material
~ Depends on climate.
~ In example, used of cavity brick to reduce heat loss
from buildings.
iii) The Direction of sunrise & sunset (Radiation)
~ The balcony is built to prevent radiation from entering
the buildings.
~ Built a window hood.
Factors in Planning & Designing

26.
iv) The condition of surrounding area
~ Eg. In industrial area
~ Building materials must be durable to acid rain
v) Precipitation
~ Heavy rain for the whole year
~ Pitch roof is used
~ Gutter built to ensure the rain water goes to the drains
~ Corridor to prevent dirty on wall
vi) AirMovement
~ Large opening for doors & window
~ Enable warm air flow outside the building.
Factors in Planning & Designing

27.
FACTORS THE
DIFFERENCE OF
WEATHERCONDITION
WITHSURROUNDING
AREABALKHIZ ISMAIL . FSPU, UiTM SARAWAK

28.
1) Radiation
~ Direct radiation – esp. in the desert, no obstruction
~ Indirect radiation – Vegetation – obstruct the sun
radiation
2) Humidity
~ Different region/place will experience the different
humidity/moisture content of air.
~ It’s depends on the amount of rainfall & evaporation
process
Factors – Weather vs. Surrounding

29.
3) Altitude
~ The higher the place, the temperature is become lower
~ Eg : Fraser Hill, Cameron Highland
4) Vegetation
~ Vegetation (trees) absorbed the heat / radiation.
~ Evaporation rate is reduce.
Factors – Weather vs. Surrounding

30.
THANK YOU