3. The most important elements
of climate and weather
parameters that affect
human comfort and are
relevant to building design are:
SOLAR
RADIATION
LONG WAVE
RADIATION
TEMPERATURE
HUMIDITY
WIND
PRECIPITATION
ELEMENTS
OF CLIMATE
4. SOLAR RADIATION
Sky condition is usually
indicated in terms of the
degree and frequency of
cloud cover, and may be used
in calculations of luminance of
daylight factors for building
interiors, and also for decisions on
shading devices.
A solarimeter is a pyranometer,
a type of measuring device
used to measure combined
direct and diffuse solar
radiation.
An integrating solarimeter
measures energy developed
from solar radiation based on
the absorption of heat by a
black body
The SI standard for
measuring solar radiation is the
watt per square meter (W/m2).
Solar radiation values will be required
for estimation of the amount of heat reaching
the inside of a building envelope. A simple
sunshine recorder produces a burn track on a
cylinder of paper each time the sun is
exposed, but a wide range of more
sophisticated devices are now used.
SOLARIMETER
5. A pyranometer is a type
of actinometer used for
measuring solar irradiance on a
planar surface and it is designed
to measure the solar radiation
flux density (W/m²) from the
hemisphere above within a
wavelength range 0.3 μm to 3
μm.
Thermopile pyranometers
A thermopile pyranometer (also
called thermo-electric pyranometer) is a
sensor based on thermopiles designed to
measure the broad band of the solar
radiation flux density from a 180° field of
view angle. A thermopile pyranometer thus
usually measures 300 to 2800 nm with a
largely flat spectral sensitivity.
PYRANOMETER
6. Photoelectric pyranometer - silicon
photodiode
Also known as a photoelectric
pyranometer in the, a photodiode-based
pyranometer can detect the portion of
the solar spectrum between 400 nm and
1100 nm. The photodiode converts the
aforementioned solar spectrum
frequencies into current at high speed,
thanks to the photoelectric effect. The
conversion is influenced by the
temperature with a raise in current
produced by the raise in temperature
(about 0,1% • °C)
Photoelectric pyranometer -
photovoltaic cell
Built around the 2000s concurrently
with the spread of photovoltaic
systems, the photovoltaic
pyranometer is a derivation of the
photodiode pyranometer.
7. LONG WAVE RADIATION
Long wave Radiation
is electromagnetic radiation of
wavelengths from 3–100 μm emitted
from Earth and its atmosphere out to
space in the form of thermal radiation.
It is also referred to as up-welling long-
wave radiation and terrestrial long-
wave flux, among others.
A pyrgeometer is a device that measures
near-surface infra-red radiation spectrum in
the wavelength spectrum approximately from
4.5 μm to 100 μm.
It measures the resistance/voltage changes in
a material that is sensitive to the net energy
transfer by radiation that occurs between
itself and its surroundings .
PYRGEOMETER
8. TEMPERATURE
Temperature is usually expressed
as a monthly mean, but average
monthly maximum and minimum
values may be preferable.
Unit measure in Celsius
MERCURY THERMOMETER (Micro level)
Respond quickly to temperature changes
Uniform expansion
Does not wet (cling to the sides) of the
tube
It is a good conductor of heat (High
thermal conductivity)
9. STEVENSON SCREEN
It is made up of wood: i.e. to prevent absorption
and conduction of heat.
Panted white or silver grey;- In order to reflect
sunshine.
Stands are 1 metre high:- to avoid the influence of
ground conditions.
The sides and floor are made of louvers or slats to
allow free circulation of air and to keep off direct
sun rays.
It has an insulated roof to create a bad conductor
of heat. This is done by creating an air space
between the layers of the roof.
The roof is slanting to avoid the accumulation and
stagnation of rain water.
It stands on grass covered ground.
It is fixed or placed far from buildings or obstacles
to avoid any interference.
10. Water or other liquid
diffused in a small
quantity as vapour, within
a solid, or condensed on
a surface. Moisture causes
slight wetness or
dampness in the
surroundings.
Density of moist air versus pressure ranges from 75 - 1000
mm Hg. Humidity is the water vapor present in air where
commonly used terms are Absolute, Specific and Relative
Humidity. The enthalpy of humid air consists of latent heat.
Absolute humidity is the measure of water vapor (moisture)
in the air, regardless of temperature. It is expressed as grams
of moisture per cubic meter of air (g/m3).
Specific humidity, mass of water vapour in a unit mass of
moist air, usually expressed as grams of vapour per kilogram
of air, or, in air conditioning, as grains per pound.
Specific humidity, mass of water vapour in a unit mass of
moist air, usually expressed as grams of vapour per kilogram
of air, or, in air conditioning, as grains per pound. .
HUMIDITY
PROPERTIES:
11. UNITS
Absolute humidity unit - g.m-3
Specific humidity unit - g.kg-1
Relative humidity is unitless.
HOW TO CALCULATE MOISTURE ?
Indoor: laser Hygrometer is used.
Outdoor: Digital thermohygrometer
A thermo-hygrograph or hygrothermograph is
a chart recorder that measures and records
both temperature and humidity (or dew point).
12. WIND
Wind velocity, is a fundamental atmospheric quantity
caused by air moving from high to low pressure,
usually due to changes in temperature.
Properties: it moves from high to low pressure . cold
temperature means high pressure in area and hot
temperature means low pressure in area.
Units: m/s
13. Cup anemometers are
used in macro scale to
know windspeed.
Hand held
anemometers are used
in micro scale . these
are digital.
Direction of wind is
found using wind vane.
14. PRECIPITATION
Precipitation,
which includes rain, hail and
dew, is measured in mm/time
units, using a rain gauge. Data
are collated in a form which
indicates the pattern of dry and
wet seasons. Also useful are
'ever recorded' maxima and
minima, and maxima in any 24
hr period, which will provide
degrees of deviation from
average, and prediction factors
for flooding.
15. Rain gauge (Micro
level)
The main characteristics of the
rain gauge are:
1)It is a meteorological device.
2)It measures rain, drizzle, hail,
snow and sleet.
3)It measures neither mist nor
dew.
4)It is cylindrical, and one of its
parts is funnel-shaped
Rainfall Measurements by Radar
(Macro level)
In an integrated system for measurement of rainfall, rain gauges are
used for measuring the total amount as well as intensity of a
rainstorm and a microwave radar (wavelength ~ 3 to 10 cm) is used
for determining the areal extent, location, and movement of
rainstorms. Also the amount of rainfall over large areas can be
determined using radars with a good degree of accuracy.
The hydrological range of the radar is about 200km.
Heavy rains – 10 cm radar
Light rains and snow – 5cm radar
Doppler type radars are used for measuring the velocity and
distribution of raindrops.
16. This image shows us that as we move from
the equator to the arctic, with the decrease
in temperature we have the tropical,
temperate, subarctic and arctic regions. But
as we move from a wet climatic condition to
dry climatic conditions, we can see a lot of
changes in the moisture content in the
atmosphere. Though tropical climates have a
pretty warm temperature and a high
moisture content as we move from the rain
forest to the desert region. The high
moisture regions here also show heavy
rainfall during most of the time of the year
and the dry regions have a high temperature
throughout the year. Colombia, Venezuela,
Peru are a good example of such climatic
conditions.
DIAGRAM
ANALYSIS
17. The temperate region has a moderate
climate all year round the heavy
moisture regions in the temperate
regions have the most comfortable
climate but as we go to the drier region,
we have the same climatic conditions
such as the deserts in the tropical
climate. Argentina, Uruguay etc. are a
good example of such climatic
conditions.
The subarctic region has a pretty low temperature and a
moderately low amount of humidity throughout the whole
region. The trees here are coniferous and a glimpse of snow
can be seen during most of the time of the year. The climatic
conditions here are moderately cold throughout the year due
less amount of sunlight falling in this part of the earth the less
moisture content also makes this region less humid all year
round. Most regions of Siberia, Canada and Alaska show this
type of climatic conditions.
The poles are basically referred to as the arctic region. They
have very low temperature all year round and the moisture
content of the region is also low all year round. Such low
temperature and moisture content make human life pretty
harsh in such regions. This region is filled with snow glaciers
and covered in snow throughout the year. The lifestyle in such
regions is different than what can be seen in the other parts
of the earth.