(a) Weather is the condition of the lower atmosphere of a place over a short period while climate is the average of the weather conditions of a place. The weather of any given place changes from day to day while climate is comparatively constant over a long time
(b) Elements: Temperature, rainfall, wind, humidity, pressure, cloud and sunshine.
Description
(i) Temperature: Heat within the air indicates how hot or cold a place is and varies from latitude to latitude. The sun is the source of all heat and measured with the aid of thermometer. It influences the actual amount of water vapour present in the air and also the rate of evaporation and condensation in the lower atmosphere Temperature decreases with heights
(ii) Pressure: Consists of a number of mixed gases and has weight, exerts weight on the earth surface and this varies from place and from time to time. The higher one goes the lower the temperature and pressure. It is measured with a barometer.
(iii) Cloud: Particles of water droplets in the upper atmosphere suspended in the air. Due to condensation of water vapour carried by rising air, clouds may give precipitation. Cloud reduces visibility and depletes solar insolation. Types include cirrus, cumulus, status, etc.
(iv) Sunshine: Visible part of the solar energy and useful for plants and other living organisms. Determines how dry the wind is and aids the process of formation of clouds and rainfall. The amount of sunshine depends on latitude of a place and the slope of the land affects the amount/intensity of sunshine. Sunshine aspect may affect the amount/ intensity of sunshine. Sunshine varies according to season.
(iv) Rainfall: Water droplets from the atmosphere. Occurs as a result of evaporation from water bodies, rivers, lakes, oceans and transportation from plants. Condensation reaches saturation point, dew point is finally reached. Amount of rainfall is measured with the aid of a language. Types of rainfall are convectional, orographic and cyclonic
(vi) Wind: Air in motion, from high pressure to low pressure belts and has direction. It is made up of series of gusts and eddies, capable of carrying moisture, dust and other pollutants and it adapts to the characteristics of its immediate environment. Measured with wind vane (for direction) while the speed is measured with an anemometer
(vii) Humidity: A measure of dampness of the atmosphere, water in the gaseous state; it varies from place to place at different times of the day. Two types: absolute and relative and it is measured with hygrometer
(c) Uses of rainfall data:
(i) To determine the characteristics of rainfall
(ii) For agricultural purposes
(iii) For calculation of monthly mean rainfall
(iv) For calculation of mean annual rainfall
(v) For planning social activities
(vi) For air and sea navigation purposes
(vii) For planning military operations
(viii) For educational purpose (teaching and research)