Western disturbances play an important role in large part of India’s winter climate and agriculture. In light of this statement, discuss the genesis and impact of Western disturbances.
- Introduce with western disturbances
- Talk about their genesis
- Write the impact of western disturbances on India
- Conclude appropriately
Western disturbances are phenomenon that are mostly active during India’s winters, impacting North and North-west India with rainfall, snowfall and fog. The frequency of western disturbances varies from year to year, but on an average 3 to 5 disturbances are experienced per month from November to March. The resultant changes in weather conditions have both positive and negative impact on agriculture and thus socio-economic conditions of the people.
Disturbance means an area of “disturbed” or reduced air pressure, and as the disturbances travels from West to East, they are termed as western disturbances. They originate in Mediterranean sea and enter India with moisture content augmented from the Caspian sea and the Persian Gulf on the way and cause winter rainfall in Northern India. This movement of the western disturbances is associated with sub-tropical westerly jet stream, which blows at a very high speed during winter over the sub-tropical zone. In winter season, the southern branch of this jet stream shifts towards topic of cancer and flows along 25 degree north latitude. This jetstream is responsible for bringing western disturbances form the Mediterranean region to the subcontinent.
- Western Disturbances along with their induced systems are the principle rain producing systems during non-monsoonal months over North India including Punjab, Haryana, Uttar Pradesh and Delhi. Their effect sometime extends up to Gangetic plains and Northeast India.
- They are also responsible for bringing snowfall in the higher reaches of Jammu & Kashmir, Himachal Pradesh and Uttarakhand.
- Western Disturbance brings winter and pre-monsoon rain and is important for the development of the Rabi crop in the Northern subcontinent. Considering that wheat is one of the most important Rabi crops, which is the staple diet of people in this region, winter showers contribute to India’s food security.
- Sometime, due to severe rainfall/ snowfall, it damages the rabi crops. Pulses are also get affected.
- As the western disturbance will be bringing more moisture, there will be an increase in fog. Low visibility problems will increase in Delhi-NCR, Uttar Pradesh, Punjab and Haryana.
The climatic phenomena like western disturbances lead to variation from typical monsoon climate in India, and has significant impact on weather, sustainability of agriculture & socioeconomic conditions.
Subjects : Geography – Physical