THE KENYA POLYTECHNIC UNIVERSITY COLLEGE
SCHOOL OF APPLIED SCIENCES AND TECHNOLOGY
DEPARTMENT OF EARTH,ENVIRONMENTAL SCIENCE AND TECHNOLOGY.
COURSE:ENVIRONMENTAL RESOURCE MANAGEMENT
RESEARCH ON:WEATHER MEASURING INSTRUMENTS.
NAME:AKELLO CLAIRE NASIKE
PRESENTED TO:MADAM GACHAHI
WEATHER MEASURING INSTRUMENTS.
Weather is the day to day conditions of the atmosphere of a given place or location.different weather elements have
different measurements and this include:pressure,rainfall/precipitaion,evaporation,sunshine,wind,humidity,
temperature and cloud cover.
1 AIR PRESSURE
Is the pressure exerted by the weight of the atmosphere.it can be measured using a mercury barometer or an
It has a glasstube with a height of atleast 84cm,closed at one end,with an open mercury filled reservoir at the base.
The weight of the mercury creates a vacuum in the top of the tube.mercury in the tube adjusts until the weight of the
mercury column balances the atmospheric force exerted on the reservoir.high atmospheric places more force on the
reservoir,forcing mercury higher in the column.low pressure allows the mercury to drop to a lower level in the
column by lowering the force placed on the reservoir.since higher tempeeratures at the instrument will reduce the
density of the mercury,the scale for reading the height of the mercury is adjusted to compensate this effect.
No liquid is needed in the aneroid barometer.it consists of a metal box from which much of the air has been
removed.a strong spring prevents it from collapsing.any change in the atmospheric pressure will cause the box to
expand or flatten slightly.as the movements are very small,a system of levers magnifies these small movements of
the box.the system of levers then causes a pointer to rotate over a circular scale which shows the atmospheric
pressure in centimetres or inches.
It is the amount of water condensed from atmospheric vapour falling in drops within a given area in a given time.
Rainfall is measured using a raingauge which are of various types and they include:
a)standard or graduated cylinders
It consists of a funnel attached to the graduating cylinder that fits into a large container.if the water overflows from
the graduated cyinder the outside container will catch it.when measurements are taken,the cylinder will be
measured and then the excess will be put in another cylinder and measured.in most cases,the cylinder is marked in
mm.the larger container collects any rainfall amounts over 25mm that flows from a small hole near the top of the
cylinder.a metal pipe is attached to the container and can be adjusted to ensure the raingauge is level.this pipe then
fits over a metal rod that has been placed in the ground.
It consists of a storage bin,which is weighed to record the mass.certain models measure the mass using a pen on a
rotating drum,or by using a vibrating wire attached to a data logger.the advantages of this type of gauge over
tippingbuckets are that it does not underestimateintense rain,and it can measure other forms of precipitation
including hail and snow.their disadvantage is that they are,however more expensive and require more maintenance
than tipping bucket gauges.
c)tipping bucket gauge
consists of a large copper cylinder set into the ground.at the top of the cylinder is a funnel that collects and
channels the precipitation.the precipitation falls onto one of two small buckets or levers which are balanced in the
same manner as a scale.after an amount of precipitation equal to 0.2mm(0.007 in)falls,tthe lever tips...
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