Weather Instruments

WEATHER INSTRUME

NTS

BASIC WEATHER

PARAMETERS AND

INSTRUMENTS USED

1.Temperature

Thermometer is an instrument for measuring temperature.

Mercury is the liquid used in the maximum thermometer which has a narrowed passage called a constriction in the bow of the glass tube just above the bulb.

A minimum thermometer contains a liquid of low density like alcohol.

The thermograph is an instrument that records air temperature on

graph paper.

Thermometer Shelter

2. Atmospheric Pressure The atmospheric pressure on a given

surface is the force exerted per unit area by overlying column of air extending to the outer limit of the atmosphere.

Barometer is an instrument for measuring atmospheric pressure.

Two types of barometer:

Mercurial Barometer Aneroid Barometer

3. Surface Wind Velocity and Directions

Wind vaneis an instrument used to indicate wind direction

Anemometermeasures the wind speed and is normally made of cups which are rotated by the motion of the wind.

Aerovaneindicates both the wind direction and wind speed or simply the wind velocity in a remote wind indicator panel.

is used to measure relative humidity.

SLING-PSYCHOMETER

is a hygrometer and thermograph combination and records both relative humidity and temperature on a graph paper.

Hygrothermograph

Hygrometeris an instrument used to measure the moisture content of a gas, as in determining the relative humidity of air.

is any product of the condensation of atmospheric water vapor that falls under gravity. The main forms of precipitation include drizzle, rain, sleet, snow, graupel and hail. It occurs when a local portion of the atmosphere becomes saturated with water vapour and the water condenses.

4. PRECIPITATION

DRIZZLE

RAIN

SLEET

SNOW

GRAUPEL

HAIL

5. Cloudsare condensed water vapor carried aloft and are either composed of water droplets or ice crystals depending upon their altitude and temperature conditions.

Thank You!