Students should refer to Climate ICSE Class 10 Geography notes provided below designed based on the latest syllabus and examination pattern issued by ICSE. These revision notes are really useful and will help you to learn all the important and difficult topics. These notes will also be very useful if you use them to revise just before your Geography Exams. Refer to more ICSE Class 10 Geography Notes for better preparation.
ICSE Class 10 Geography Climate Revision Notes
Students can refer to the quick revision notes prepared for Chapter Climate in Class 10 ICSE. These notes will be really helpful for the students giving the Geography exam in ICSE Class 10. Our teachers have prepared these concept notes based on the latest ICSE syllabus and ICSE books issued for the current academic year. Please refer to Chapter wise notes for ICSE Class 10 Geography provided on our website.
Climate ICSE Class 10 Geography
Climate ICSE Class 10 Geography Notes
TOPIC-1
Distribution of Temperature, Rainfall and Winds
Quick Review
➢ India has a tropical monsoon type of climate.
➢ The temperature varies from region to region due to the vastness of the country and topographical differences.
➢ The difference between the highest and the lowest temperature in a year is the Annual Range of temperature.
➢ The northern part of India which lies beyond the Tropic of Cancer (23½°N) experiences continental type of climate i.e. too hot in summer and too cold in winter.
➢ The extremity of this climate is due to its distance from the sea. The northern part of the country is situated far away from the influence of the sea.
➢ The southern part of India lying in the tropical region between 8°N and 23½°N experiences moderate temperature. The regions lying close to the coasts experiences equable climate.
➢ Due to the proximity of the sea, the southern coastal regions experiences equable or maritime or oceanic type of climate.
➢ The rainfall is mainly Relief or Orographic. It is due to the presence of mountain ranges.
➢ The moisture laden winds in summer blow from sea to land and strike the Windward side of the mountain causing heavy rainfall while the other side of the mountain called the Leeward side receives scanty rainfall.
➢ Rainfall is erratic, uncertain and unpredictable due to its variation from time to time. Thus, sometimes it causes floods or droughts.
➢ In India, rainfall occurs mainly in summer.
➢ During summer, the moisture laden winds blow from the Arabian Sea branch and bring heavy rainfall to the western, central and northern regions due to the presence of the Western Ghats and the lofty Himalayas.
➢ The Eastern coastal region receives scanty rainfall in summer but receives heavy rainfall in winters due to the Retreating N.E. winds.
➢ Besides the summer monsoon, the North Western region also receives rain in winter due to the cyclonic winds that originate over the Mediterranean Sea and blow towards India.
➢ The rainfall is also unevenly distributed. Some regions like Rajasthan receives less than 50 cms of rainfall, the central part and the Deccan plateau receives low rainfall of about 80 cms while place like Mawsynram near Cherrapunji receives 2500 cms of rainfall.
➢ The distribution of rainfall depends on the relief of the land, direction of the winds from the sea and the path of the cyclonic winds.
➢ Due to increasing temperature in summer, the winds become hot and dry and affect local areas strongly. Loo is a local wind that blows in the northern part of the country in the month of May and June and causes heat strokes. It is a gusty, hot and dry wind.
➢ Similarly, Kalbaisakhi is a local wind that blows in West Bengal and Assam in the month of April, which is accompanied with thunderstorms and heavy rainfall.
➢ This rain is beneficial for the growth of tea in Assam and rice and jute in West Bengal.
➢ Mango Showers or Cherry Blossoms are also the local winds which blow in Kerala during summers in June. This wind helps in the growth of mango, coffee and tea.
➢ In winter, the winds blow from land to sea from the north east direction. These winds are dry and slow in process.
➢ The North Western region also receives the cyclonic winds blowing from the Mediterranean Sea and influences the Northern plains.
Know the terms
➢ Climate : The atmospheric condition which prevails over an area for a longer period of time usually over a span of 30 years.
➢ Continental Climate : It is experienced in the interior part of the country away from the influence of the sea with very hot summers and cold winters. It is also called extreme climate.
➢ Equable Climate : It is experienced near and along the coasts due to the influence of the sea with summers and winters not very hot or cold respectively. There is not much difference in the temperature throughout the year.
➢ Relief Rainfall : Due to the presence of mountains (relief feature), the moisture laden winds blowing from the sea strikes the mountain and cause heavy rainfall.
➢ Windward Side- The side of the mountain facing the moisture laden winds which causes heavy rainfall after striking the mountain. E.g. western side of the Western Ghats.
➢ Leeward Side or Rain Shadow Area : The other side of the mountain which receives scanty or less rainfall. It is also the Rain shadow area. E.g. Deccan Plateau.
➢ Loo : It is a local wind that blows in the northern part of the country and causes heat strokes. It is a gusty, hot and dry wind.
➢ Kalbaisakhi : It is a local wind that blows in West Bengal and Assam in the month of April, which is accompanied with thunderstorms and heavy rainfall. This rain is beneficial for the growth of tea in Assam and rice and jute in West Bengal.
➢ Mango Showers or Cherry Blossoms : These are the local winds which blow in Kerala during summers. This wind helps in the growth of mango, coffee and tea.
Flowchart
TOPIC-2
Factors Affecting Climate and Seas
Quick Review
➢ Climate refers to the atmospheric condition that prevails on a large area over a long period of time.
➢ There are a number of factors responsible which influences the climate of India- the Himalayas, the monsoon winds, latitude, altitude, distance from sea, western disturbances, etc.
➢ The Himalaya acts as a climate divide. It prevents the South-West moisture laden winds from crossing over it which results in heavy rainfall in the entire Indian Sub-Continent. It also protects from the cold Siberian winds from entering the Indian region
➢ The Monsoon Winds bring summer rainfall over the whole of South Asia. The South West monsoon winds moves from the Arabian Sea branch and the Bay of Bengal branch to the low pressure areas of north and north-west India.
➢ These winds bring heavy rainfall during summers from June to September. In October when it withdraws and retreats, it picks up moisture from the Bay of Bengal and shed good amount of rainfall on the eastern coastal plain of India. The winds blowing over the land are cold and dry.
➢ The important line of Latitude, the Tropic of Cancer passes through the middle of India dividing it into two zones- Temperate Zone (Northern part) and the Tropical Zone (Southern part). The southern tropical zone remains warm throughout the year and practically has no winter season.
➢ The places beyond the Tropic of Cancer never experiences overhead sun while all the places in the southern zone experiences overhead sun twice a day.
➢ Relief is also an important factor in affecting the climate of India. The Western Ghats stands as a barrier on the way of the South-West monsoon winds which comes from the Arabian Sea and results in heavy rain on the western coastal plains.
➢ The Himalayas in the extreme north prevents the moisture laden winds from crossing it and thus causes heavy rainfall in the major portion of the India Sub-Continent. The Aravalli Range in the west runs parallel to the South West monsoon winds and thus doesn’t shed any rainfall in that region.
➢ Higher the Altitude, lower the temperature. It is due to normal Lapse Rate, i.e. for every rise of 166 metres there is a decrease of 1°C of temperature. Thus, the mountains are cooler than the plains.
➢ The three major surrounding seas- Indian Ocean, Arabian Sea and Bay of Bengal have a great influence and impact on the climate. They are the major source of rain in India and also due to its proximity; the coastal places have moderate climatic conditions.
➢ During the winter season, due to the Western Disturbances over the Mediterranean Sea, the westerly cyclonic winds blow towards India and bring the north- west part of India under its influence. These cyclonic winds bring rain to the North West part of India.
➢ Air currents which determine the arrival and departure of the monsoons are known as Jet Streams. The westerly jet streams prevail over the northern plains while the easterly jet streams steers the tropical depression over India.
➢ Due to the distance from the sea, the areas far away from the influence of the sea experiences continental type of climate, i.e. too hot in summers and too cold in winters. The coastal places, on the other hand, experiences equable or maritime climate due to the nearness of sea. The land breeze and sea breeze are caused due to the differential heating and cooling of land and sea.
➢ El-Nino is a warm ocean current which increases the surface temperature of the sea and affects the monsoon winds in the Indian Ocean. It causes weak drought-like situation in the Indian Sub-Continent.
➢ Monsoons are periodic seasonal winds and are caused due to differential heating and cooling of land and sea.
➢ Monsoons are divided into two wind systems- the Summer Monsoon and the Winter Monsoon.
➢ In India, on the basis of monsoon variations, the year may be categorized into four main seasons. They are-
(i) The Hot Summer Season (March to May)
(ii) The Hot and Wet or Rainy Season (June to September)
(iii) The Retreating South West Monsoon (October-November)
(iv) The Cold and Dry Winter Season (December-February)
➢ The Hot Summer Season begins in March when the sun starts moving northwards and shines vertically over the Tropic of Cancer. During this period, the temperature rises up and goes upto 48°C.
➢ Due to the moderating influence of the sea, the heat is not so intense in the southern part of India. Plateaus and hills are also cool due to its elevation.
➢ The Rainy season begins in June and continues till September. The differential heating and cooling of land and sea develops intense low pressure over the large landmass and intense high pressure over the seas.
➢ The moisture laden monsoon winds enter the Indian mainland from the south west direction and brings heavy rainfall accompanied by thundering and lightning.
➢ The sudden violent onset of rainfall in the first week of June is termed as the Burst of the Monsoon.
➢ Kerala is the first state to receive the monsoon showers and the last to see it retreat.
➢ The South West monsoon is divided into two branches-
(i) The Arabian Sea Branch
(ii) The Bay of Bengal Branch
➢ After the monsoon, in the month of October, the South-West Monsoon begins to retreat from the northern part of India and is thus called Retreating Monsoon.
➢ During this period, due to the apparent movement of the sun, the low pressure trough is gradually replaced by high pressure.
➢ The retreating winds are dry and slow in their process. The combination of high temperature and humidity gives rise to an oppressive weather, termed as October Heat.
➢ Due to local variations of heat and moisture, tropical depressions originate in the Bay of Bengal which leads to tropical cyclones.
➢ By the end of November the winter season begins and continues till March. The temperature decreases from South to North. January is the coldest month.
➢ The north east winds prevail over the country during the winter season and blow from land to sea. When part of these winds blow over the Bay of Bengal, they pick up moisture from there and strike the Eastern Ghats, thereby, shedding heavy rainfall along the coastal plains.
➢ A characteristic feature of the winter season is the inflow of cyclonic winds coming from the west. These cyclonic winds, caused due to low pressure systems, originate over the Mediterranean Sea and are called Western Disturbances.
➢ These winds bring heavy rainfall over the plains of the north-west part of India in the winter season.
➢ The distribution of rainfall is determined by the following situations:
(i) The pressure conditions
(ii) The direction of relief features
(iii) The direction of the wind bearing moisture
(iv) Cyclonic depression.
➢ Main features of rainfall in India are as follows:
(i) Rainfall occurs only for three months during the rainy season.
(ii) The rains are mainly of relief type i.e. the windward side of the mountain receives more rainfall than the leeward side of the mountain.
(iii) Less rainfall is received from the other sources like the conventional rainfall and the cyclonic rainfall.
(iv) Rainfall is mainly erratic in nature.
(v) India being an agrarian country is dependent on rainfall which affects its economy.
Know the terms
➢ Climate : It refers to the atmospheric condition that prevails on a large area over a long period of time.
➢ Temperate zone : The region beyond the Tropic of Cancer (23½°N) where the sun is never overhead.
➢ Tropical zone : The region between the Equator and the Tropic of Cancer where the overhead sun is experienced twice a year.
➢ Western Disturbances : The cyclonic depressions that originate over the Mediterranean Sea and bring good amount of rainfall in the North West part of India in the winter season.
➢ Jet Streams : Air currents which determine the arrival and departure of the monsoons.
➢ El-Nino : It is a warm ocean current which increases the surface temperature of the sea and affects the monsoon winds in the Indian Ocean.
➢ Monsoon : It is derived from the Arabic word Mausim which means season. These are periodic seasonal winds and are caused due to differential heating and cooling of land and sea.
➢ Burst of the Monsoon : The sudden violent onset of rainfall in the first week of June accompanied by thundering and lightning.
➢ Retreating Monsoon : The withdrawal of monsoon in the month of October from the mainland of Indian Sub-Continent.
Flowchar
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