Class IX – Climate

Ans. Weather refers to the state of the atmosphere over an area at any point of time.

Ans. Climate refers to the sum total of weather conditions and variations over a large area for a long period of time i.e., more than thirty years.

Ans. (i) Monsoon refers to the seasonal reversal in the wind direction during a year.

(ii) The word monsoon is derived from the Arabic word ‘mausim’ which literally means season.

Ans. In summer, the mercury occasionally touches 50°C in some parts of the Rajasthan desert, whereas it may be around 20°C in Pahalgam in Jammu and Kashmir.

Ans. In the Thar desert, the day temperature may rise to 50°C and dropdown to near 15°C the same night.

Ans. Rajasthan is a very hot place so people build houses with thick walls that are hard for heat to penetrate while the flat roofs help to retain the little water that comes as rain in the desert.

Ans. The houses in Tarai region, Goa and Mangalore have sloping roofs so that the rain water in these area flows off the roof.

Ans. The houses are built on stilts in Assam as there is a danger of floods and wild animals in large areas of Assam.

Ans. Most of the World’s deserts are located in the western margins of the continents in the sub-tropics because trade winds that blow in the region shed their moisture on the eastern side. They become dry by the time they reach the western margins of the continent.

Ans. Sea has a moderating influence on the climate. As the distance from the sea increases its moderating influence decreases and the people experience extreme weather conditions i.e., very hot during summers and very cold during winters.

Ans. The Tropic of Cancer passes through the middle of the country from the Rann of Kuchchh in the west to Mizoram in the east.

Ans. The duration of the monsoon is between 100-120 days from early June to mid-September.

Ans. A characteristic feature of the cold weather season over the northern plains is the inflow of cyclonic disturbances from the west and north-west.

Ans. In peninsular India, the temperatures remain lower due to the moderating influence of the oceans.

Ans. The ‘Loo’ are strong, gusty, hot dry winds blowing during the day over the north and northwestern India.

Ans. This relates to localized thunderstorms, associated with violent winds, torrential downpours, often accompanied by hail. The name is used in West Bengal because it occurs in the month of Baisakh.

Ans. ‘Mango showers’ are premonsoon showers common especially in Kerala and Karnataka. They help in the early ripening of mangoes.

Ans. Mawsynram, the wettest place on the earth is also reputed for its stalagmite and stalactite caves.

Ans. (a) The western cyclonic disturbances are weather phenomena of the winter months brought in by the westerly flow from the Mediterranean region.

(b) (i) They usually influence the weather of the north and north-western regions of India.

(ii) Tropical cyclones, occur during the monsoon, as well as in October-November.

(iii) These cyclones are part of the easterly flow.

(iv) these disturbances affect the coastal regions of the country, particularly in Odisha and Andhra Pradesh coast.

Ans. (a) The Inter Tropical Convergence Zone (ITCZ) is a broad trough of low pressure in equatorial lattitudes.

(b) This is where the northeast and southeast trade winds converge.

(c) This convergence zone lies more or less parallel to the equator but moves north or south with the apparent movement of the sun.

Ans. (i) El Nino is a name given to the periodic development of a warm ocean current along the coast of Peru as a temporary replacement of the Cold Peruvian Current.

(ii) El Nino is a Spanish word meaning ‘the child’ and refers to baby Christ as this current starts flowing during Christmas.

(iii) The presence of the El Nino leads to an increase in sea-surface temperatures and weakening of the trade winds in the region.

Ans. (a) It is an apparent force caused by the earth’s rotation.

(b) (i) The Coriolis force is responsible for deflecting winds towards the right in the northern hemisphere and towards the left in the southern hemisphere.

(ii) This is also known as ‘Ferrel’s Law’.