GS Paper 1:
Topics Covered: changes in critical geographical features (including water-bodies and ice-caps) and in flora and fauna and the effects of such changes
Context:
The India Meteorological Department (IMD) has predicted a cold wave in parts of Punjab, Haryana, Chandigarh, Gujarat, Rajasthan, and Uttar Pradesh over the next few days.
Conditions for declaring cold waves:
The IMD records a cold wave when the minimum temperature is equal to or less than 10 degrees Celsius at a weather station in the plains and is 4.5 degrees to 6.4 degrees below the normal temperature for that period.
For hilly regions, a cold wave is declared when the minimum temperature is less than or equal to 0 degrees Celsius and the minimum temperature is 4.5 degrees to 6.4 degrees below the normal.
Reasons for the Cold wave conditions in India:
- Impact of Western disturbance: Cold wave conditions form due to lack of western disturbances. Western disturbances create precipitation and bring down day temperatures, but night temperatures remain steady.
- Snowfall in the upper Himalayas: This creates a wind chill factor for the northern states of India
- Downward subsidence of cold air: Subsiding air (from the upper Himalayas) further cools down creating low-temperature conditions over North India for a longer period.
- La Nina is known to favor cold waves in North India.
- It increases the severity of cold conditions, also the frequency and area covered under the grip of a cold wave become larger e.g. winters of October 2020 were colder than usual (2 degrees Celsius, the lowest since 1962) due to the impact of La Nina in the pacific.
Impact of cold wave conditions:
- Impact on agriculture in North India: It creates a wider gap between day and night temperatures, this creates erratic winter conditions impacting agricultural practices in the Rabi season.
- Impact on Cash crops: It might also affect the productivity of cash crops such as coffee (Coffee growth is extremely sensitive to variations in temperatures), which grows mainly in south India.
- Impact on Human life: Cold wave conditions increase the risk of contracting flu, and could also lead to symptoms like nosebleeds and runny nose. It was also said to be responsible for the 2nd wave of COVID 19 in many parts of North India.
Sources: The Indian Express
Insta Curious:
Analyze the reasons behind the extra cold winters in parts of north India this year. (250 words) Reference
What is Magnetic Reconnection with respect to the sun’s surface? Reference
InstaLinks:
Prelims Link:
- Western Disturbances.
- La Nina
Mains Link:
How does the La Nina influence the cold wave conditions in winters of north India?
