Weather Instrument Weather Element and Measuring Instrument
Anemometer

Element: Wind Speed

Instrument: Anemometer

An instrument which measures wind speed.

Wind Vane

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.

Wind Sock

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 especially 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.

Aneroid Barometer

Element: Atmospheric Pressure

Instrument: Aneroid Barometer

A type of barometer used to measure atmospheric pressure.

Digital Barometer

Element: Atmospheric Pressure

Instrument: Digital Barometer

A type of barometer used to measure atmospheric pressure.

Barograph

Element: Atmospheric Pressure

Instrument: Barograph

An instrument that continuously records and provide a graphical representation of atmospheric pressure.

Campbell-Stoke Sunshine Recorder

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 char 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 trace, less gaps, is proportional to the duration of sunshine.

Ceilometer

Element: Cloud Height

Instrument: Ceilometer

A ceilometer is a device that uses a laser or other light source to determine the height of a cloud ceiling or cloud base. Ceilometers can also be used to measure the aerosol concentration within the atmosphere.

Evaporation Pan

Element:

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.

Hygrometer

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).

Psychrometer

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.

Thermo-hygrograph

Element: Temperature and Humidity

Instrument: Thermo-hygrograph

An instrument which measures the environmental temperature and humidity at the same time, usually both continually.

Stevenson Screen

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.

Thermometer

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.

Maximum Temperature

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.

Minimum Temperature

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.

Dry Bulb Temperature

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.

Wet 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

Manual Rain GaugeManual Rain Gauge

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. Generally, an open receptacle with vertical sides is used, usually in the form of a right cylinder, with a funnel if its main purpose is to measure rain. 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.

Automatic Raingauge

Element: Rainfall

Instrument: Automatic Raingauge

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. The use of the other two types for the most part is limited to the measurement of rainfall.