7th Class Science Winds, Storm and Cyclones Weather Forecasting

       Weather Forecasting

Weather forecasting is the process in which the observation of the atmosphere of a particular place, in a particular duration is made. Weather at a particular place depends on its atmospheric pressure, speed of wind and temperature. Observation of weather is observed by automatic weather stations or buoys. Weather satellites give the overall coverage of the earth's atmosphere. Radar gives the information about the weather by radiation or IR (infrared). There after it is analyzed in comparison with previously recorded data. Temperature, humidity, rain gauge are the common parameters of weather. A thermometer is used to measure the temperature. Mercury or alcohol inside it expands on heating. Barometer is used to measure air pressure. An increase in the reading of barometer represents sunny and dry weather while falling reading of barometer represents stormy condition. A rain gauge indicates the amount of rain fall within a time period. An anemometer indicates the speed of wind. These all instruments are used to record the weather of a particular place and after analyzing the recorded data weather forecast is made.

Look at the following picture of Stevenson screen

In the picture above, a Stevenson screen is shown, which is used for the temperature or humidity measurement of atmosphere. Covers of the Stevenson screen protect it from destructive elements. Holes on the walls allow air passing through it. Stevenson screen is an important measuring instrument in the weather station.

         Weather forecast is partly depended on raw data from measuring instrument and partly from previous recorded data. The raised reading of barometer in the weather forecasting station represents which one of the following?

(a) Stormy weather

(b) Sunny and dry weather

(c) Rain fall

(d) All of these

(e) None of these

Answer: (b)

The equator of the Earth is at 0° latitude. South Pole is at 90°(S) latitude, and North Pole is at 90°(N) latitude.

Weather and climate is effected by atmospheric pressure.

Motion of air is due to the uneven heating of the Earth.

The layers of atmosphere above the Earth's surface are troposphere, stratosphere, mesosphere, thermosphere, and exosphere.

Exerted pressure on the Earth by the atmosphere is called the atmospheric pressure..