Climate (India)

Statement 1 is correct: The whole of India, despite being the location of its northern portion in subtropical region, experiences ‘tropical monsoon climate’. This is the manifestation of the influence of Himalayas on the Indian subcontinent.
Statement 2 is incorrect: There are no winters in equatorial regions.

Statement 1 is correct: India experiences winter monsoon due to two reasons:

1. Influence of western disturbances in the North-West India.
2. Influence of permanent North-East trade winds in South-East India along the Coromandel Coast.

Statement 2 is also correct: Monsoons are seasonal winds that change their directions with respect to the temperature-pressure dynamics. They flow from high pressure or low temperature area to low pressure or high temperature area. In summers, the Asian landmass gets heated due to northward movement of the sun. Hence, the Indian subcontinent witnesses summer monsoons due to the change in pressure conditions in the subtropical landmass of Asia due to increase in temperature.

The south-west monsoon winds, after arriving at the southern tip of the Indian peninsula, get divided into two branches - (1) Arabian Sea branch, and (2) Bay of Bengal branch.
The Arabian Sea branch blows in south-westerly direction. But the Bay of Bengal branch gets deflected towards north-west due to three factors - (1) Arakan Hills of Myanmar, (2) Himalayas of the North India and (3) Thermal low pressure over North India. This leads to change in the direction of this branch from south-westerly to south-easterly direction.

All the given factors influence the nature and mechanism of monsoons.

The south-west monsoon winds, after arriving at the southern tip of the Indian peninsula, get divided into two branches - (1) Arabian Sea branch, and (2) Bay of Bengal branch.
Both these branches of winds blow towards the interior parts of land. But the farther they move from the sea, the lesser becomes their rain bringing capacity.
The Arabian Sea branch gets almost water deficient reaching the foothills of the Shiwaliks. Getting reinforced by the Bay of Bengal Branch, the Arabian Sea branch of monsoon winds brings some showers to the Western Himalayas in the summer season.
It should be kept in mind that the Western Himalayas receive rainfall in winter season from the Western disturbances.

The jet stream is a river of wind that blows horizontally through the upper layers of the troposphere, generally from West to East at an altitude of 20,000 - 50,000 feet (6,100 - 9,144 metres) or about 7 miles (11 kilometres) up.
There are different jet streams and in respect of the climate and monsoons of India, it is the Subtropical Jet Stream (STJ) and the countering easterly jet that are most important.
As the summertime approaches, there is increased solar heating of the Indian subcontinent. This has a tendency to form a cyclonic monsoon cell situated between the Indian Ocean and southern Asia. This cell is blocked by the STJ which tends to blow to the South of the Himalayas; as long as the STJ is in this position, the development of summer monsoons is inhibited. During the summer months, the STJ deflects northwards and crosses over the Himalayan Range. The altitude of the mountains initially disrupts the jet, but once it has cleared the summits, it is able to reform over central Asia. With the STJ out of the way, the sub-continental monsoon cell develops very quickly indeed, often in a matter of a few days.
In winters, an easterly jet stream, called the tropical easterly jet stream blows over peninsular India, approximately over 14°N during the summer months. Thus, it affects most part of Indian climate throughout the year.

Characteristics of evening dust storms that blow in north-western India during May:

1. They are non-permanent or temporary in nature and blow in the heart of the low pressure trough in the north-west direction.
2. They are dry day winds
3. They may prove fatal
4. These storms along with the oppressive heat of the season add challenges to human life.

The Sun is vertically over the equator on 21^st March, after which it starts moving northwards. Now keeping this in mind, a student may mark 'option 4', i.e. Tamil Nadu as the answer. But, it should be kept in mind that the 'moderating influence of adjacent Bay of Bengal lowers the temperature of the state, and it is Maharashtra (among the given states) that witnesses the highest temperature in March.
The Western Himalayas reduces the similar moderating influence of Arabian Sea on the interior regions of Maharashtra.

Statement 1 is incorrect: Monsoons are seasonal winds that change their direction with respect to the temperature-pressure dynamics. They flow from high pressure or low temperature area to low pressure or high temperature area. During cold weather season, a feeble high temperature area is developed in the northern part of India and strong winds with a high velocity of 30-50 km per hour begin to blow outwards.
Statement 2 is perfectly correct: Before reaching the north-western part of the country, the Western disturbances that originate over the Mediterranean Sea travel eastwards across West Asia, Iran-Afghanistan and Pakistan, with their moisture content augmented from Caspian Sea in north and Persian Gulf in south.

Convectional rainfall occurs when the energy of the sun (or insulation) heats the earth’s surface and causes water to evaporate, finally changing to water vapour. This warm, moist air then rises, and as it rises it cools. The air reaches a point called the condensation level where it has cooled to such an extent that the water vapour condenses and turns back to a liquid form. This process of condensation high in the atmosphere leads to the development of clouds. As the clouds continue to grow the weight of the water droplets can eventually lead to precipitation.
Deserts experience convectional type of rainfall. In deserts, the diurnal range of the temperature is very high. They receive high insolation during the day time in absence of cloud cover, and reflect back this heat during night.

Statement 1 is correct: Mean monthly values of various variables like temperature, rainfall and other weather elements give an idea about the climate of a place.
Statement 2 is incorrect: Such mean values of these variables are obtained from records relating to a period of around 35 years.
Statement 3 is correct: Climatic maps are one of the best methods to represent average climatic conditions for a month, season or year as a whole.

Mist is a phenomenon caused by small droplets of water suspended in air. The only difference between mist and fog is visibility. This phenomenon is called fog if the visibility is one kilometre (1,100 yards) or less. Otherwise it is known as mist. Seen from a distance, mist is bluish, and haze is more brownish. In case of haze, visibility is less than 5/4 miles. In case of smog, visibility may reduce to 220 yards or even less.

Statement 1 is correct: Pattern of winds is always a manifestation of pressure-temperature dynamics. The pattern of planetary winds is modified by the centres of high pressure and low pressure.
Statement 2 is incorrect: Winds blow in anticlockwise direction around a low pressure centre (i.e. cyclone) and in clockwise direction around a high pressure centre (i.e. anti-cyclone).
Statement 3 is incorrect: Wind speed is not the criterion for classification of monsoon winds. Monsoon winds are rather, characterised by seasonal reversal of wind direction.

Statement 1 is correct: During December to February, light winds of low velocity blow over the Ganga-Brahmaputra Delta in the northerly direction.
Statement 2 is incorrect: The very light rainfall brought by Western disturbances is highly beneficial for Rabi crops, especially wheat.
Statement 3 is correct: Incursion of the pre-monsoon showers and early advance of the monsoons further north is checked by a belt of relatively high air pressure lying over the Deccan Plateau.

All the statements, except statement 3, are correct. Coromandel Coast is the coastal area of Tamil Nadu and southern Andhra. This area does not experience summer rain due to parallel direction of the rain bearing winds. Instead, this region gets rain in winter season from the north-east jet streams.