Climate Flashcards
Differentiate between Climate and Weather
Climate
* Sum total of weather conditions and variations over a large area in a long period of time
* The weather conditions of a large area for more than 30 years
Weather
* State of atmosphere over an area at any point of time
* Day to day phenomenon
On what basis are seasons divided upon
- On the basis of the generalised monthly atmospheric conditions, the year is divided into seasons.
What type of climate does India have?
- India is described as having a “monsoon” climate
- Monsoon refers to the seasonal reversal in the wind direction during a year
- This type of climate is found in South and Southeast Asia
How does temperature vary within the country?
- In summer, it may be around 50 C in Rajasthan while it may be around 20 C in Jammu and Kashmir
- On a winter night, it can go up to -45 C at Drass in Jammu and Kashmir while Thiruvananthapuram might be around 22 C
- In the Thar desert, temperature can rise up to 50 C in the morning and hit as low as 15 C in the night
- Whereas, in places like Kerala and Andaman and Nicobar Islands, the day and night temperatures do not differ much.
How does precipitation vary within the country?
- There is variation not only in its form but also in its amount
- Precipitation takes place as snowfall in the upper parts of Himalayas while it rains over the rest of the country
- The annual precipitation varies from 400 cm in Meghalaya to 10cm in Rajasthan
How does the variation in weather affect the lives of people
- Coastal areas experience less contrasts in temperature conditions
- Season contrasts are more in the interior of the country
- There is decrease in rainfall generally from east to west in the Northern Plains
- These variations have given rise to variation in lives of people:
- In the food they eat
- The clothes they wear
- The houses they live in
Give some examples on how houses are varied within the country
- Houses in Rajasthan have thick walls and flat roofs because:
- Thick walls prevent heat from entering the house
- Flat roofs help retain the little water collected from rainfall
- Houses in Mangalore and Goa have sloping roofs to move down the water to the ground due to heavy rainfall
- Houses in Assam are built on stilts to avoid flooding of houses
What are the major controls of climate in any place?
There are 6 major controls of climate in any place:
1. Latitude
2. Altitude
3. Pressure and Wind System
4. Distance from Sea
5. Ocean Currents
6. Relief Features
How does latitude affect temperature?
- Due to the curvature of the Earth, the amount of solar energy received varies upon latitude
- As a result, the air temperature decreases from the equator to the poles
How does altitude affect climate?
- As one goes from the surface of the Earth to higher altitudes, the atmosphere becomes less dense and the temperature decreases
- Therefore, hills are cooler than plains during summer
How does pressure and wind system affect climate?
- Pressure and Wind System is dependent on latitude and altitude
- Thus, it influences the temperature and rainfall pattern
How does distance from sea affect climate?
- As the distance from the sea increases, its moderating influence decreases and the people experience extreme weather conditions
- This condition is known as continentality (very hot in the summers and very cold in winters)
How do ocean currents affect climate?
- Ocean Currents along with onshore winds affect the climate of coastal areas.
- For example, any coastal area with warm or cold currents flowing past it, will be warmed or cooled if the winds are onshore.
How do relief features affect the climate?
Relief plays a major role in determining the climate of a place
* High mountains act as barriers from cold or hot winds.
* They may cause precipitation if they are high enough and lie in the path of rain-bearing winds
* The leeward side of mountains remain relatively dry
Why are deserts usually found in the western margins of continents?
- The ocean currents that pass by the western margins of continents are cold as they come from the poles
- As the ocean currents are cold, the rate of evaporation is less, hence clouds will not be formed
- As a result, there will be little or no precipitation in these regions, causing it to become a desert.
What are the factors affecting India’s climate
- Latitude
- Altitude
- Pressure and Winds
How does latitude affect India’s climate?
- The Tropic of Cancer passes through the middle of the country from the Rann of Kuchchh in the west to Mizoram in the east
- The half of the country that lies south to the Tropic of Cancer belongs to the tropical area
- The other half that lies north of the Tropic of Cancer belongs to the sub=tropics
- Therefore, India’s climate has characteristics of tropical and sub-tropical climates
How does altitude affect India’s climate
- India has mountains in the north with an average height of 6000m
- It also has a vast coastal area with a maximum height of 30m
- The Himalayas prevent the cold winds from Central Asia from reaching the Indian subcontinent.
- This is why India experiences milder winters than Central Asia
What are the atmospheric conditions that affect India’s climate?
The climate and weather conditions of India are governed by the following atmospheric conditions:
* Pressure and surface winds
* Upper air circulation
* Western cyclonic disturbances and tropical cyclones
How does pressure and surface winds affect India’s climate
- During winters, there is a high pressure area north of the Himalayas
- These cold and dry winds blow towards the low pressure area in the south
- However during summers, a low pressure area develops over interior Asia
- This causes a complete reversal of the direction of winds during summer
- Air moves from the high pressure area over the Southern Indian Ocean, crosses the equator and turns right towards the low pressure areas over the Indian subcontinent
- These are known as Southwest Monsoon winds
- These winds blow over the warm oceans, gather moisture and bring widespread rainfall over the mainland of India
What are the major seasons in India?
- India has a monsoon type of climate
- It is distinguished by a distinct seasonal pattern
- The weather conditions greatly change from one season to another
- These changes are mostly noticeable in the interior parts of the country
- The coastal areas do not experience variation in temperature but they do experience variation in rainfall
- There are 4 main seasons in India:
The Cold Weather Season (Winter)
The Hot weather Season (Summer)
The Advancing Monsoon (Rainy)
The Retreating Monsoon (Transition)
What are the characteristics of cold weather season in India?
- The cold weather season begins from mid-November and stays till February
- December and January are the coldest months
- The temperature decreases from south to north
- The average temperature of:
Chennai is between 24-25 C
Northern plains is 10-15 C - Days are warm and nights are cold
- Frost is common in north India and higher slopes of the Himalayas experience snowfall
- This season is characterised by:
- Clear skies
* Low temperature
* Low humidity
* Feeble and variable winds
- Clear skies
- In northern India, a feeble high pressure area develops with winds moving outwards from this area.
- Due to the relief, this wind moves through the Ganga valley from the west and northwest
Why does Tamil Nadu experience rainfall during winters?
- The north-easterly winds flow from land to sea in most parts of India
- However it flows from sea to land in the Tamil Nadu Coast
- Hence, some amount of rainfall occurs in Tamil Nadu coast during winter
What is the impact of Western Cyclonic Disturbances during winter on India
- These disturbances originate in the Mediterranean Sea and Western Asia and move towards India along with the westerly flow
- They cause winter rains over the plains and snowfall over the mountains
- This rainfall is locally known as “mahawat”
- They are very important for the growth of rabi crops
