NCERT Solutions for Class 9 Geography Chapter - 4 Climate

(i). (b) Mawsynram

(ii). (b) Loo

(iii). (c) Early June

(iv). (c) Cool days and cold nights

(i). The controls affecting the climate of  India are temperature, atmospheric pressure, wind, humidity, and precipitation.

(ii).  India comes in the Inter Tropical Convergence Zone (ITCZ) and together with factors such as El Nino, Coriolis Force, and Jet Streams, India gets a unique type of climate which is called the Monsoon type of climate in India.

(iii). The North-western part of India experiences the highest diurnal range of temperature as it receives the least amount of rainfall and also it is also away from the sea. So, the temperatures go to the extreme in this part of India.

(iv).  The Malabar Coast gets most of the rainfall from the Southwest monsoon winds. Sometimes, although rare, this coast experiences cyclones as well which bring rainfall.

(v). Monsoon break takes place due to the reversal of the wind direction. This includes a wet and dry spell during the rainy season during which very little rainfall takes place.

(vi).  The monsoon in India influences almost all of the Indian Subcontinent and most of the activities take place based on these winds. The flora and fauna thrive in the subcontinent due to the monsoons and the crops are grown successfully based on the timings of the monsoons. Many festivals also take place based on the monsoon across India. So, the monsoon is called a unifying bond in India.

The rainfall in the eastern part of India occurs due to the Bay of Bengal branch of southwest monsoons. As the winds move from Bengal to the Gangetic plains, their moisture content decreases, and by the time they reach the Punjab region, they are almost dry. So, a decrease is seen in the amount of rainfall from east to west.

(i). The seasonal reversal of wind direction over the Indian subcontinent takes place due to pressure differences. The El Nino also plays a major role in the seasonal reversal of wind direction over the Indian subcontinent.

(ii). The monsoon season begins in India in June and by mid-July, it covers almost all of the Indian Subcontinent. The retreat of monsoons begins in September and not much rainfall occurs after that. Hence, in the Indian subcontinent, the rainfall is concentrated over a few months.

(iii). The Tamil Nadu coast, known as the Coromandel Coast receives winter rainfall as the north-eastern winds, which are retreating monsoon winds take up moisture as they move over the Bay of Bengal during winters and pour the rains due to obstruction from the Eastern Ghats. Since the Coromandel Coast falls on the windward side, it gets winter rainfall.

(iv). The Bay of Bengal is the center of various pressure changes so many cyclones develop in this region. Hence, the delta region of the Bay of Bengal witnessed multiple cyclones.

(v). The parts of Rajasthan, Gujarat, and the leeward side of the Western Ghats are drought-prone as the Arabian Sea branch does not give enough rainfall in that region as it falls on the leeward side. The Aravalli mountains lie parallel to the direction of the winds so they do not force the winds to cause rains. Also, the Bay of Bengal branch becomes dry till it reaches Rajasthan.

There is a huge regional variation in the climatic conditions of India. The Temperature and Precipitation vary not only from place to place but also from season to season.

• In summer, the temperature goes up to 50°C in certain parts of Rajasthan but it barely crosses 20°C in Pahalgam in Kashmir region.

• In winter, the night temperature in the Dras sector of Kashmir is below the freezing point of around -45°C but in Thiruvananthapuram, Kerala it hardly goes below 20°C.

• In the Andaman and Nicobar Islands, the difference between day and night temperatures is barely 7° – 8°C.

• The coastal areas experience less contrast in the temperature, whereas the seasonal contrasts are more in the interior of the country.

• There is a decrease in rainfall generally from east to west in the northern plains.

• Most parts of India get rainfall from June to August - September, whereas the Coromandel Coast gets rainfall in the winter season. Odisha gets rainfall from cyclones too.

The following are the features of the cold season in India:

• The winter season begins in mid-November and continues till February in northern India.

• December and January are the coldest months in the northern part of India which consists of Punjab, Delhi, Himachal Pradesh, etc.

• The average temperature ranges between 10°-15°C in the northern plains, while it ranges around 24°-25°C in Southern India.

• The northeast trade winds prevail over the entire country in this period. As these winds blow from land to sea, most parts of the country experience a dry climate.

• The weather is usually marked by clear skies, low temperatures, low humidity, and weak variable winds.

• The inflow of cyclonic disturbances from the west and the northwest is a characteristic feature of the cold weather over the northern plains of India.

• These low-pressure systems originate over the Mediterranean Sea and Western Asia and move into India. They cause winter rains over the northwestern plains and snowfall in the mountains.

• The winter rainfall is in small amounts but is very important for the rabi crops which are harvested in March - April.

• The peninsular region does not get a well-defined winter because of the moderating influence of the sea and its location in the Torrid Zone.

The characteristics of the monsoon rainfall in India are:

• The duration of the monsoon varies from 100 to 120 days which is from early June to mid-September.

• Around the time of its arrival, the normal rainfall increases suddenly and continues regularly for several days. This is also called the ‘burst’ of the monsoons.

• The monsoons are distinguished from the pre-monsoon showers because of their increase in rainfall amount and regularity.

• The monsoon arrives at the southern tip of the Indian Peninsular generally by the first week of June.

• The rainfall is unevenly distributed across the country. The effects of the monsoon rainfall in India:

• The agriculture in India largely depends on Indian monsoons for water. Late, low, or excessive rains have a highly negative impact on crops.

• Due to uneven distribution of rainfall across the country, few places are drought-prone such as Marathwada and Vidarbha and few are flood-prone such as Assam.

• The monsoon provides India with a diverse climatic pattern.