Meterological instruments

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ASSIGNMENT
ON
Various Instruments For Measurement of Meteorological Elements
SUBMITTED TO: SUBMITTED BY:
Dr.(Mrs) Shweta Gautam Suman Kumar Dey
Assistant Professor Id. No: 19MSAGRO070
College of Forestry M.Sc. Ag.(Agronomy)
NAI,SHUATS II semester
NAINI AGRICULTURAL INSTITUTE,
FACULTY OF AGRICULTURE,
SAM HIGGINBOTTOM UNIVERSITY OF AGRICULTURE, TECHNOLOGY
AND SCIENCES,
PRAYAGRAJ, 211007

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Meteorological observations are made for a variety of reasons. They are used for the real-
time preparation of weather charts and maps, for weather forecasts and severe weather
warnings, for the study of climate, and for local weather-dependent operations.
Meteorologists use a wide variety of instruments to measure weather conditions. These
data are required for analysis in hydrology and agricultural meteorology, and for research
in meteorology and climatology.
Various elements are-
1)Wind speed,
2)Wind direction,
3)Atmospheric pressure,
4)Sunshine duration,
5)Cloud height & type,
6)Evaporation,
7)Humidity,
8)Temperature,
9)Rainfall,
10) Visibilit
11) Snow cover
12) Soil temperature

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Element: Wind Speed
Instrument: Anemometer
An instrument which measures wind speed.
Element: Wind Direction
Instrument: Wind Vane
A device that measures the direction of the wind. It spins
on a rod and points in the direction from which the wind
blows. The part of the vane that turns into the wind is usually
shaped like an arrow. The other end is wide so it will catch
the smallest breeze.
Element: Wind Direction
Instrument: Wind Sock
A light, flexible cylinder or cone mounted on a mast to
show the direction and strength of the wind. Wind sock is
commonly used at an airport or chemical plant. The cone-
shaped bag opened at both ends so that it extends
horizontally as the wind blows through it and indicates the
wind direction by pointing away from the wind.
Element: Atmospheric Pressure
Instrument: Aneroid Barometer
A type of barometer used to measure atmospheric pressure.
Element: Atmospheric Pressure
Instrument: Digital Barometer
A type of barometer used to measure atmospheric pressure.

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Element: Atmospheric Pressure
Instrument: Barograph
An instrument that continuously records and provide a
graphical representation of atmospheric pressure.
Element: Sunshine Duration
Instrument: Campbell-Stoke Sunshine Recorder
Campbell-Stokes Pattern Sunshine Recorder employs a glass
sphere to focus the sun's rays to an intense spot, which will
burn a mark on a curved card mounted concentrically with
the sphere. As the earth rotates the position of the spot
moves across the card. When the sun is obscured, the trace is
interrupted. At the end of the day the total length of the burn
or trace, less gaps, equals the duration of sunshine hours.
Element: Evaporation
Instrument: Evaporation Pan
A type of evaporation gauge or evaporimeter; it is a pan used
in the measurement of the evaporation of water into the
atmosphere over specified periods of time.
Element: Cloud Height & type
Instrument: Ceilometer
A ceilometer is a device that uses a laser or other light source
to determine the height of a cloud ceiling or a cloud base
from the ground. Ceilometers can also be used to measure the
aerosol concentration within the atmosphere.
Element: Humidity
Instrument: Hygrometer
An instrument used to measure the humidity, or amount of
water vapour in the atmosphere. The sensing mechanism of
the instrument can be hair (hair hygrometer), a plate coated
with carbon (electrical hygrometer), or an infrared sensor
(infrared hygrometer).

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Element: Humidity
Instrument: Psychrometer
A hygrometer composed of two similar thermometers. The
bulb of one thermometer is kept wet (by means of a thin, wet
cloth wick) so that the cooling that results from evaporation
makes it register a lower temperature than the dry-bulb
thermometer. When readings are taken simultaneously, it is
possible (with the use of psychrometric tables) to determine
the relative humidity and dew-point temperature of the air.
Element: Temperature
Instrument: Thermometer
Measures how hot or cold the atmosphere is in (Celsius (C)
or Fahrenheit (F), or Kelvin (K)). A traditional thermometer
consists of mercury, red spirit or green spirit in a glass tube
and operates on the principle that the liquid expands more
than the glass does when heated.
Element: Temperature and Humidity
Instrument: Thermo-hygrograph
An instrument which records the environmental temperature and
humidity at the same time, usually both continually.
Element: Temperature and Humidity
Instrument: Stevenson Screen
A standard shelter for housing four types of thermometers: dry,
wet, maximum and minimum. The screen shields the instruments
from direct sunlight.

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Element: Temperature
Instrument: Maximum Temperature
Maximum temperature has historically been measured with a
mercury-in-glass thermometer which has a constriction in the neck
of the thermometer tube. As the air temperature rises mercury is
forced past the constriction. However, as the temperature falls the
constriction prevents the mercury from returning to the bulb of the
thermometer. The height of mercury in the tube remains at that
reached at the hottest time of day. The thermometer is reset by
gentle shaking.
Element: Temperature
Instrument: Minimum Temperature
Alcohol-in-glass thermometers containing a moveable index are
used to manually record minimum temperatures. When the
temperature falls, the liquid and index move down the column,
but when the temperature rises the index remains in the lowest
position while the liquid expands up the tube. The position of the
index indicates the lowest temperature reached since the last reset
which is achieved by tilting the thermometer, bulb end upwards.
Element: Temperature
Instrument: Dry Bulb Temperature
usually referred to as ‘air temperature’. When people refer to the
temperature of the air they are normally referring to the dry bulb
temperature.
Element: Temperature
Instrument: Wet Bulb Temperature
Wet Bulb temperature can be measured by using a thermometer
with the bulb wrapped in wet muslin. The adiabatic evaporation of
water from the thermometer bulb and the cooling effect is indicated
by a "wet bulb temperature" lower than the "dry bulb temperature"
in the air.
The evaporation from the wet muslin is reduced when air contains
more water vapor.
By combining the dry bulb and wet bulb temperature in a
psychrometric chart the state of the humid air can be determined

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Element: Rainfall
Instrument: Rain Gauge
An instrument that measure the amount of rain that falls during a
given time interval usually in millimetres or inches. The total
amount of rainfall which reaches the ground in a stated period is
expressed as the depth to which it would cover the earth if it were
all flat and level, and if there were no loss by evaporation, or if
there was no runoff or infiltration.
The standard rain gauge takes the form of a collector above a
funnel leading to a receiver with some sort of measuring device.
Sometimes the amount of rain is poured carefully into a measuring
cylinder or dip rods or a ruler dipped into the receiver to determine
the amount.
Element: Rainfall
Instrument: Automatic Rain gauge
Three types of automatic precipitation recorders are in general use:
the weighing recording, the tilting or tipping-bucket type and the
float type. Only the weighing type is satisfactory for measuring all
kinds of precipitation such as . The use of the other two types for
the most part is limited to the measurement of rainfall.
Element: Visibility
Instrument: Transmissometer
A transmissometer is used for measuring the atmospheric
transmittance at visibility deterioration (fog, rain etc.).
This instrument is mainly installed at the runways of airports in
order to determine the visual range for the flight control safety
service.
Element: Snow cover
Instrument: Snow gauge
A snow gauge is a type of instrument used by meteorologists and
hydrologists to gather and measure the amount of solid
precipitation (as opposed to liquid precipitation that is measured
by a rain gauge) over a set period of time.

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Reference
1) https://en.wikipedia.org/wiki/Meteorological_instrumentation
2) www.weather.gov.dm/resources/weather-elements-and-instruments-used-
for-measurement
3) www.weather.gov › epz › Guide to Meteorological Instruments and Methods
Element: Soil temperature
Instrument: Bimetal Thermometer
soil thermometer. (Also called earth thermometer)
A thermometer used to measure the temperature of the soil.
Two forms of the mercury-in-glass thermometer are used for
this purpose