With reference to the mechanism of weather in the winter season in Ind...
Explanation:
The mechanism of weather in the winter season in India is influenced by various factors. Let's analyze each statement given in the question:
Statement 1: The weather conditions over India are influenced by the distribution of pressure in Central and Western Asia.
This statement is correct. The distribution of pressure in Central and Western Asia plays a crucial role in determining the weather conditions over India. During winter, a high-pressure area known as the Siberian High develops over Central Asia. This high-pressure system causes cold air to move towards the Indian subcontinent, leading to a drop in temperatures. The cold and dry winds from the Siberian High flow towards India, resulting in the winter season.
Statement 2: The western cyclonic disturbances enter the Indian subcontinent.
This statement is also correct. During the winter season, the western disturbances, which are cyclonic disturbances originating in the Mediterranean region, enter the Indian subcontinent. These disturbances bring moisture-laden winds from the Mediterranean Sea and cause rainfall in the northern parts of India, including the Himalayan region.
Statement 3: The jet stream flowing south of the Himalayas merges with the one flowing north of the Tibetan highlands.
This statement is incorrect. The jet stream flowing south of the Himalayas does not merge with the one flowing north of the Tibetan highlands. In fact, the jet stream flowing south of the Himalayas is known as the Subtropical Jet Stream, while the one flowing north of the Tibetan highlands is known as the Polar Jet Stream. These two jet streams have different paths and do not merge.
In conclusion, both statements 1 and 2 are correct, while statement 3 is incorrect. Therefore, the correct answer is option 'A' - 1 and 2 only.
With reference to the mechanism of weather in the winter season in Ind...
In winter months, the weather conditions over India are generally influenced by the distribution of pressure in Central and Western Asia. Hence statement 1 is correct.
- A high pressure centre in the region lying to the north of the Himalayas develops during winter.
- This centre of high pressure gives rise to the flow of air at the low level from the north towards the Indian subcontinent, south of the mountain range.
- The surface winds blowing out of the high pressure centre over Central Asia reach India in the form of a dry continental air mass.
- These continental winds come in contact with trade winds over northwestern India.
- The western cyclonic disturbances which enter the Indian subcontinent from the west and the northwest during the winter months, originate over the Mediterranean Sea and are brought into India by the westerly jet stream. Hence statement 2 is correct.
- All of Western and Central Asia remains under the influence of westerly winds along the altitude of 9-13 km from west to east. These winds blow across the Asian continent at latitudes north of the Himalayas roughly parallel to the Tibetan highlands. These are known as jet streams.
- Tibetan highlands act as a barrier in the path of these jet streams.
- As a result, jet streams get bifurcated and One of its branches blows to the north of the Tibetan highlands, while the southern branch blows in an eastward direction, south of the Himalayas. It has its mean position at 25°N in February at 200-300 mb level. Hence statement 3 is not correct.
- It is believed that this southern branch of the jet stream exercises an important influence on the winter weather in India
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