Social Science SHORT ANSWER QUESTIONS(3 Mark)

The delta region of the eastern coast is frequently struck by cyclones because the cyclonic depressions which originate over the Andaman Sea generally cross the Eastern coasts of India and cause heavy and widespread rain.

1. These cyclones are often very destructive. The thickly populated deltas of the Godavari, the Krishna and the Kaveri are frequently struck by cyclones which cause great damage to life and property.
2. Sometimes these cyclones arrive at the coasts of Odisha, West Bangal and Bangladesh.

During the winter season, the north-west trade winds prevail over the country. They blow from land to sea and hence for most part of the country it is a dry season.
Some amount of rainfall occurs on the Tamil Nadu coast from these winds as here they blow from sea to land.

In summer, a low pressure area develops over interior Asia as well as over north western India.

1. 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.
2. These are known as the south-west monsoon winds.
3. These winds blow over warm oceans, gather moisture and bring widespread rainfall over the mainland of India.
4. The duration of the monsoon is between 100-120 days from early June to mid September. Thus, we can say that rainfall in India is concentrated over a few months.

During winter, there is a high pressure area north of the Himalayas. Cold winds blow from this region to the low pressure areas over the oceans to the south.

1. In summer, a low pressure area develops over interior Asia as well as over north-western India.
2. This causes a complete reversal of the direction of winds during summer.

The western coast and northeastern India receive over about 400cm of rainfall annually.However, it is less than 60cm in western Rajasthan and adjoining parts of Gujarat, Haryana and Punjab. Rainfall is equally low in the interior of the Deccan plateau, and east of the Sahyadris. A third area of low precipitation is around Leh in Jammu and Kashmir. The rest of the country receives moderate rainfall. Snowfall is restricted to the Himalayan region. Owing to the nature of monsoons, the annual rainfall is highly variable from year to year. Variability is high in the regions of low rainfall such as parts of Rajasthan, Gujarat and the leeward side of the Western Ghats. As such, while areas of high rainfall are liable to be affected by floods, areas of low rainfall are drought-prone.

Monsoon refers to the seasonal reversal in the wind direction. Monsoon ‘break’ refers to the happening of wet and dry spells during the rainy season. The monsoon rains take place only for a few days at a time.

Here are five main types of precipitation, rain, snow, sleet, freezing rain, and hail. Before we start comparing the types of precipitation, let's review how precipitation happens. All forms of precipitation are the result of the water cycle, or the movement of water between the Earth and the atmosphere.

The change in pressure conditions over the Southern oceans affects the monsoon as:

1. When the tropical Eastern South Pacific Ocean experiences high pressure, the tropical Eastern Indian Ocean experiences low pressure. In this condition, the monsoon rainfall will be average.
2. In some years, it is reverse when pressure difference is negative- means below average and late monsoon.
3. The change in pressure conditions is connected to the EL Nino.

High-velocity dust storms swept across parts of North India and more than 125 people died and over 200 were injured. five states– Rajasthan, Uttar Pradesh, Telangana, Uttarakhand, and Punjab.

The total amount of winter rainfall locally known as 'mahawat' is small, they are of immense importance for the cultivation of rabi crops. Kaal baisakhi: In summer local thunderstorms, associated with violent winds, torrential downpours are often accompanied by hail.

The Himalayas prevent the cold winds from Central Asia from entering the subcontinent. It is because of these mountains that this subcontinent experiences comparatively milder winters as compared to central Asia.

The northern plains have higher ranges of temperature then other areas of the world at the similar latitude because norther plains lie interior of the country, these plains are far from any maritime affect. This region experience continentally hence it's tempreature is higher.

Drass in Jammu and Kashmir have a very low temperature Because the Drass is located at an altitude of about 10,597 above the sea level.

Eastern part of Tamilnadu in south India receive rainfall in summer because of Indian monsoon and in winter it receive rainfall because of retreat monsoon. Coromandel coast receives rainfall both in summer and winter.

A regional variation generally refers to times when a radio station or television station simultaneously broadcasts different programmes, continuity or advertisements to different parts of its coverage area.

During winter monsoon, the North-East trade winds are moisture laden as they blow from land to sea. Therefore, most of the part of the country do not get rainfall and is dry season. They are called land bearing winds as these winds are planetary. This is because of the northeast trades wind during winter season there will be no rainfall.

The months of October-November form a period of transition from hot-rainy season to dry winter conditions. The retreat of the monsoon is marked by clear skies and rise in temperature. While day temperatures are high, nights are cool and pleasant. The land is still moist. Owing to the conditions of high temperature and humidity, the weather becomes oppressive during the day. This is commonly known as October heat.

Differences between weather and climate:

S.No	Weather	Climate
(i)	It refers to the state of the atmosphere at any point of time and place.	It refers to the sum of total weather conditions and variations over an area for a long period of time.
(ii)	Weather conditions change frequently. It may vary at intervals of a few hours or a few days.	It does not change so frequently.
(iii)	Weather data are recorded at a specific time.	It is recorded for a longer period of more than 30 years.

Air moves from the high pressure area over the southern Indian ocean, in a south-easterly direction, crosses the equator, and turns right towards the low pressure areas over the Indian subcontinent. These are known as South-West Monsoon Winds.

When axis of rainfall shifts closer to Himalayas, there are large dry spells in the plains and widespread rain occurs in the mountainous catchment areas of Himalayan rivers. These heavy rains bring devastating floods causing damage to life and property in the plains.

The term '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. The term 'weather' refers to the atmosphere over an area at any point of time. The elements of weather and climate are:

• Temperature.
• Atmospheric pressure.
• Wind.
• Humidity.
• Precipitation.

Four main seasons of India are:

1. The cold weather season.
2. The hot weather season.
3. The advancing monsoons.
4. The retreating monsoons.

Desert regions have wide fluctuation between day and night temperature. Jammu and Kashmir gets high rainfall during October and November up to 28mm to 30mm.

During the winter season, north-east trade winds prevail over India. They blow from land to sea and, hence, for most part of the country, it is a dry season. These cause winter rains over the plains and snowfall in the mountains. It is because, in this region, these winds blow from sea to land, thereby carrying moisture along with them.

Amount of rainfall decreases as we go westward from West Bengal to Punjab because of the following reasons:

1. Monsoon winds emanating from Bay of Bengal Branch and Arabian sea branch accounts for most of the rainfall in the Indian sub continent Bay of Bengal branch causes maximum amount of rainfall and sheds most amount of its moisture in the Brahmaputra valley and Assam hills.
2. When these winds advance towards west they go on shedding moisture and that thus reduces the amount of rainfall from east to west.

Coriolis force is an apparent force caused by the Earth’s rotation. It is responsible for deflecting winds towards the right in the northern hemisphere and towards the left in the southern hemisphere.
Under the effect of coriolis force, the trade winds moving from sub-tropical high pressure belts to equatorial low pressure belts become north-east trade winds in the northern hemisphere and south-east trade winds in the southern hemisphere. As a result, they bring heavy rainfall to the east coast and the west coast remains dry.

1. Climate of India is strongly governed by the monsoon winds. Monsoon winds are confined to tropical lands between 20° North and 20° South.
2. In the Indian subcontinent, the Himalaya’s guide the flow of the monsoon winds bringing the whole of subcontinent under the influence of these winds.
3. These winds account for 75% to 90% of annual rainfall from June to September.
4. It is influenced by South–West monsoons, Retreating monsoon’s and North-East monsoons.

1. In the month of October, day temperatures are high, nights are cool and pleasant. The land is still moist. Monsoon winds retreat.
2. Owing to the conditions of high temperature and humidity, the weather becomes oppressive during the day. Sky is clear.
3. This condition is commonly known as October Heat.

They occur during the monsoon, as well as in October and November.

1. These disturbances affect the eastern coastal regions of India.
2. They originate over the Andaman sea and are often very destructive.

The air is always cooler at top than bottom of the land that's why the plain land areas are hotter and mountainous regions are lot more cooler. Therefore, Nainital station is cooler than Delhi in the summer season.

1. Chennai is located on the Coromandel coast. It lies in the rainshadow region of the Arabian Sea branch of S.W. monsoons. It first strikes the western coastal region and is almost exhausted by the time it reaches Chennai.
2. The Bay of Bengal branch runs nearly parallel to the Coromandel coast. So, it also fails to give rains to Chennai.
3. Besides, offshore dry winds blow over this region in the summers.

1. Main characteristic features of the tropical monsoon type of climate are.
2. In tropical monsoon type of climate, there are two dry seasons with low rainfall.

For example: in India, summers and winters are dry with only little rainfall. Rest of the country experiences hot and dry summers and cool and dry winters.

1. India has Himalayas located at its north which have an average height of 6,000 mts.
2. The Himalayas prevent the cold winds from Central Asia from entering India.
3. Himalayas are also able to stop the South West monsoon winds, which cause rainfall in the northern plains of India

1. The monsoons break there with full fury, right in the beginning of June. This month as a whole has good rains.
2. The monsoon also strikes these places directly. Their location helps them get the first and full impact of the monsoon currents.

1. Mumbai is located about 10° north of Thiruvananthapuram. The monsoon reaches here in the second week of July.
2. The first ten days of June are rainless in Mumbai, but July as a whole is very rainy for it.
3. The monsoon breaks with full force on June 1 in Thiruvananthapuram. June is rainier here than July.

1. Delhi receives more rainfall since it is better located with respect to the arrival of the monsoons and the western disturbances.
2. It gets mild rains from both the branches of S.W. monsoons as well as the western disturbances.
3. Jodhpur gets rains mainly from the Arabian Sea branch of the monsoon. Thermal heating during the summer also reduces precipitation. Winter is dryin this region.

1. The Inter Tropical Convergence Zone is a trough of low pressure in equatorial latitudes.
2. This is where the north-west and the south-east trade winds converge.
3. This convergence zone lies more or less parallel to the equator but moves north or south with the apparent movement of the Sun.

1. The monsoon is known for its uncertainties. While it causes heavy floods in one part, it may be responsible for droughts in the other.
2. The rainfall is unevenly distributed across the Indian landscape. Early in the season, the windward side of the Western Ghats receives heavy rainfall, i.e. more than 250cm.
3. The rain-shadow areas of Deccan Plateau and parts of Madhya Pradesh, Rajasthan, Gujarat and Leh receive scanty rainfall. The maximum rainfall is recorded in the north-eastern part of the country.

1. India has mountains to the north which have an average height of about 6,000 mts.
2. The Himalayas prevent the cold winds from Central Asia, from entering the subcontinent.
3. It is due to these mountains that the Indian subcontinent experiences comparatively milder winters as compared to Central Asia.

1. The Tropic of Cancer passes almost from the middle of the country.
2. Almost half of the country, lying south of the Tropic of Cancer, belongs to the tropical area.
3. All the remaining area in the north of the Tropic lies in the sub-tropical area.

Therefore, India’s climate has characteristics of tropical as well as subtropical type of climate.

1. The Tropic of Cancer passes through the middle of India from the Rann of kachchh in the west to Mizoram in the east.
2. Almost half of the country, lying south of the Tropic of Cancer, belongs to the tropical area. All the remaining area, north of the Tropic, lies in the sub-topics.
3. Therefore, India's climate has characteristics of tropical as well as sub-tropical climates.

1. The Bay of Bengal branch of S.W. monsoons approaches Shillong about a week before it touches Kolkata. So, the early start of monsoons gives Shillong more rains.
2. Shillong is also located on the 1500-metre high Meghalaya plateau. A sub-branch of the Bay of Bengal branch strikes it directly. Here the Garo, Khasi Hills capture the clouds like a funnel and cause heavy rains, i.e. more than Kolkata.

1. India has a ‘monsoon type’ of climate.
2. This type of climate is found mainly in South and Southeast Asia.
3. It is called ‘monsoonal’ since India receives pre-monsoon showers in the month of May, proper monsoon during the hot weather season, winter monsoon due to western disturbances in winter and a little rain when the monsoons retreat.

1. Climate: It refers to the sum total of the weather conditions and variations over a large area for a long period of time.
2. Weather: It refers to the state of atmosphere over an area at any point of time. The elements of weather and climate are the same.

It means wet and dry spells of rain. The monsoon rainfall takes place only for a few days at a time, these rainless intervals in between are called as “breaks in rainfall.

Monsoon is known for its uncertainties. The alteration of dry and wet spells of rains varies in intensity frequency and duration, while it causes heavy floods in one part, it may be responsible for droughts in the other.

A rain-shadow area is an area of dry land that lies on the leeward (or downwind) side of a mountain. High mountains act as barriers for cold or hot winds; they may also cause precipitation if they are high enough and lie in the path of rain-bearing winds. The leeward side of mountains remains dry, e.g., eastern slope of the Western Ghats is the rain-shadow area.

1. The alternation of dry and wet spells varies in intensity, frequency and duration.
2. It may cause heavy floods in one part and drought in the other part.
3. It is often irregular in its arrival and retreat. Hence, monsoons affect the farming schedule of millions of farmers all over the country.

Distinguish between loo and Western disturbances:

1. Loo occure in summer season while Western disturbances occure in winter season.
2. Loo is a local wind of Rajasthan (that desert) while Western disturbances is a wind of mrdeterranian sea.
3. Loo is a hot wind and harmful for humans and western disturbances is a comfort for humans.

Global Warming Causes The primary cause of air movement is the development of a horizontal pressure gradient through spatial differences in surface heating and consequent changes in air density and pressure.