Chapter 4 Climate
Climate: Sum total of the weather’s state and variation over an area for a period of more than thirty years. Weather: Status of the atmosphere in an area at any point of time. Elements of Weather and Climate: Temperature, wind, humidity, atmospheric pressure and precipitation. Climate of India: Monsoon Climatic Controls Six Major Controls of Climate Latitude Altitude Pressure and wind system Distance from the sea Oceanic currents Relief features Solar energy received by the Earth varies according to the latitude owing to the earth’s curvature. Thus, temperature decreases from the equator to the poles. The density of the atmosphere decreases with increasing altitudes resulting in a drop in temperature. Pressure and wind system of an area is dependent on the latitude and altitude of that place, thus affecting the rainfall and temperature pattern. Distance from the sea directly affects the weather conditions of a place. More the distance, more extreme the weather conditions become. The Oceanic currents and onshore winds affect the climate in the coastal areas. Factors Affecting India’s Climate Latitude: The Tropic of Cancer passes through the middle of India from the Rann of Kuchchh (West) to Mizoram (East). Hence, regions South of the Tropic of Cancer experiences tropical climate and those towards its North experiences subtropical climate. Altitude
The mountains in the north have an average height of 6000 metres that prevents the cold winds from Central Asia from entering India, thus giving the country milder winters. Pressure and Winds In winters, a high pressure area gets created towards the North of the Himalayas. Low pressure zones over oceans in the south receive cold and dry winds from the high pressure area in the Himalayas. In summers, low pressure areas form above interior and Northwestern areas of India. Due to this, the reversal of the direction of winds during summers helps the wind...