Weather Measuring Instruments

Only available on StudyMode
  • Topic: Wind, Barometer, Water vapor
  • Pages : 11 (1875 words )
  • Download(s) : 141
  • Published : March 15, 2013
Open Document
Text Preview
THE KENYA POLYTECHNIC UNIVERSITY COLLEGE

SCHOOL OF APPLIED SCIENCES AND TECHNOLOGY

DEPARTMENT OF EARTH,ENVIRONMENTAL SCIENCE AND TECHNOLOGY.

COURSE:ENVIRONMENTAL RESOURCE MANAGEMENT

UNIT:ATMOSPHERIC SCIENCE

RESEARCH ON:WEATHER MEASURING INSTRUMENTS.

COURSE CODE:At308111

REG NO:111/01211

NAME:AKELLO CLAIRE NASIKE

PRESENTED TO:MADAM GACHAHI

DATE:20.02.2012

INTRODUCTION

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

aneroid barometer.

MERCURY BAROMETER

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.

[pic]

ANEROID BAROMETER

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.

[pic]

2.PRECIPITATION/RAINFALL

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.

[pic]

b)weighing gauge

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.

[pic]

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...
tracking img