Class 9 Climate Notes PDF

**[Chapter 4--Climate Notes (Class 9)]** **Q1. Define the following terms-** I. **Monsoon** II. **Loo** III. **Kaal Baisakhi** IV. **Mahavat**- Winter rainfall is locally known as Mahavat. They are very useful for the cultivation of rabi crops. V. **Mango Shower-**Pre-monsoon showers are...

**[Chapter 4--Climate Notes (Class 9)]** **Q1. Define the following terms-** I. **Monsoon** II. **Loo** III. **Kaal Baisakhi** IV. **Mahavat**- Winter rainfall is locally known as Mahavat. They are very useful for the cultivation of rabi crops. V. **Mango Shower-**Pre-monsoon showers are common especially in Karnataka and Kerala and help in the early ripening of mangoes and are often referred as mango showers. VI. **October Heat**-During retreating monsoon, owing to the conditions of high temperature and humidity, the weather became rather oppressive during the day and is commonly known as October heat. **Q2) Differentiate between weather and climate.** **Q3). Describe the controls affecting the climate of any place.** **Q4). Explain the factors affecting India's climate.** A4). Factors affecting climate of India are- i. **Latitude-**The Tropic of Cancer passes through the middle of the country.Thus, India has characteristics of both tropical as well as sub-tropical climate. ii. **Altitude-**Himalayas prevent the cold winds from Central Asia from entering the subcontinent. Therefore, we experience comparatively milder winter as compared to central Asia. iii. **Pressure and wind --**India lie in the path of north easterly winds. However, as these winds blow over land, they carry very little moisture and cause no rainfall. **Q5). Give an account of wind & pressure system during winters & summers in India.** A5). **Winter-** 1. Pressure system- High pressure prevails over the Northern part of the country. 2. Wind- Cold & dry North East trade winds blow over the country. **Summers**- 1. Pressure system- A low pressure area develops over the Northern plains. 2. Winds- South West monsoon winds blow over the country & bring widespread rainfall. **Q6). Which part of India experiences the highest diurnal (daily) range of temperature and why?** A7). Diurnal range of temperature is highest in desert regions like Thar in Rajasthan, where the soil is sandy. a). It is because the sand absorbs heat very fast during the day & loses heat very fast at night. b). It is also located away from the sea. **Q7) Why does India have a monsoon type of climate?** Ans) This is because: 1. **Seasonal reversal of wind direction**- India lies in the region of North Easterly winds which blow from land to sea. Hence, they bring little or no rain. But, in summers, a low- pressure area develops over the North Western India. This causes complete reversal of the direction of the winds as a result the winds start to blow from sea to land & bring good amount of rains in most parts of India. 2. **The Himalayas act as a barrier for monsoon winds-** These high mountains bring the whole country under the influence of these winds. India gets 75-90% rainfall due to the monsoon, & so, its climate is named as monsoon type. **Q8). Distinguish between cold weather season (winter) and hot weather season(summer)** **OR** **Describe the major features of winters and summers in India.** **SUMMERS** **WINTERS** --------------------------------------------------------------------------------------------------------------- -------------------------------------------------------------------------------- March to May is the hot weather season in India. Mid November to February is the cold weather season in India. Temperature increases from south to north. Temperature decreases from south to north. Hot winds called loo blow over the Northern part of India. North East trade winds blow over the country. Due to high temperature low pressure develops over the Northern part. Due to low temperature high pressure develops over the Northern part. Local thunderstorms cause torrential downpour in west Bengal and pre-monsoon showers in Kerala and Karnataka. In flow of cyclonic disturbances cause rainfall in the northern part of India. **Q9).Give characteristics and affects of monsoon rainfall in India.** A13). **CHARACTERSTICS-** 1. It enters as South West Monsoon into the Indian peninsula. They blow in two branches --(a). Arabian sea branch(b). Bay of Bengal branch 2. They bring abundant moisture in the subcontinent. 3. The velocity of these winds is 30 km/h therefore, they cover the country in a month. 4. Monsoon winds tend to have breaks in rainfall. It has wet and dry spells. 5. Monsoon is known for its uncertainties which is often irregular in its arrival and retreat. **AFFECTS-** 1. Due to its uncertainty, it may cause floods in one part and drought in another. 2. It brings total change in weather conditions and determine the farming schedule. 3. Windward side of the Western Ghats receives heavy rainfall. In Ganga valley, the rainfall decreases from east to west. **Q10).Why is Monsoon considered as a unifying bond?** A14). Monsoon is considered as the unifying bond because- 1.It provides a rhythmic cycle of seasons. 2.The entire agricultural calendar in India is governed by it. 3.Most of the festivals in India are related to agricultural cycle and hence their celebration is decided by Monsoon. 4\. The river valleys which carry Monsoon water also unite as a single river valley unit. 5\. The Indian landscape, its animals, plant life are also influenced by the Monsoon. **Q11) GIVE REASONS** 1. **Why does rainfall decrease from East to West in the Northern plains?** A. The Bay of Bengal branch of Monsoon enters into India from Meghalaya and then covers Assam. The Himalayas deflects the monsoon winds towards the West over Ganga Plains therefore, they start moving from East to West & rainfall goes on decreasing in Northern plains. 2. **Tamil Nadu coast receives winter rainfall.** A. It's because Tamil Nadu gets rain from North East monsoon or retreating monsoon which reaches there after passing over the Bay of Bengal & picking moisture from there. 3. **The delta region of the Eastern coast is frequently struck by cyclones.** A. The low-pressure conditions over North Western India gets transferred to the Bay of Bengal by early November. This shift causes cyclonic depressions in Andaman Sea. These cyclones cause heavy rainfall in the delta region of East coast. 4. **Parts of Rajasthan & leeward side of Western Ghats are drought prone.** a. The Arabian Sea branch of monsoon strikes the Western slopes of Western Ghats & as the leeward side comes in the rain shadow area, they are drought prone. b. Parts of Rajasthan are drought prone as the Aravali hills lie parallel to monsoon winds. Hence, the winds fly over the area causing drought conditions. **MAP WORK-** On a political map of India mark -- Areas receiving annual rainfall of less than 20cm & over 400cm. 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