From UPSC perspective, the following things are important :
Prelims level : Cyclone Pawan
Mains level : Reason for increased cyclonic activities
With the formation of cyclone Pawan recently in the southwest Arabian Sea, the total number of cyclones in the North Indian Ocean region this year has reached the record eight.
Highest nos. of Cyclones this year
- This is the highest number of cyclones in a single year since 1976, when nine cyclonic storms had formed in the region, according to data from the IMD.
- This record might still be equalled as the IMD is tracking another depression in the east central Arabian Sea, though the system has weakened from a deep depression and is likely to de-intensify further in the coming days.
- The Arabian Sea has seen a lot of cyclonic activity in 2019.
- Five of the eight cyclones this year formed in this region, the highest in the past 117 years. Four of these were severe cyclones, which last occurred in 1902.
- Only one of these cyclones, Maha, had an impact on the mainland, with heavy rainfall in Gujarat and Maharashtra. The rest of the cyclones formed, developed and dissipated in the sea.
Intense cyclones have increased
- Six of the cyclones this year were of the ‘Severe’ or ‘Higher’ category.
- While Cyclone Kyarr in October reached super cyclone intensity with wind speeds in excess of 250 kilometres per hour (km/hr).
- Cyclone Fani in April-May and Cyclone Maha in October were of the ‘Extremely Severe’ category, with wind speeds greater than 200 km/hr.
- Cyclone Vayu, Cyclone Hikaa and Cyclone Bulbul were of the ‘Very Severe’ category.
- There were six ‘Severe’ cyclones in 2018 as well.
- The last time there were more than five ‘Severe’ cyclones in two consecutive years was 1976-77 when seven and five ‘Severe’ cyclones formed respectively, according to IMD data.
What enhanced cyclonic activity?
- The reason could be the active phases of both, the Indian Ocean Dipole and Madden Julian Oscillation phenomena.
- The second could be global warming, which has led to warmer-than-usual temperatures on the surface of seas and oceans.
- This provides the perfect conditions for the formation of low pressure areas which can intensify into depressions and further into cyclones.
- In September, the World Meteorological Organization (WMO) had said that the world will be witness to warmer-than-usual surface and sea temperatures in the latter part of 2019.
- It had also said that this was a clear sign of global warming in the absence of the El Nino phenomenon, which had ended in August.
- Also according to the WMO, the leaning towards above normal temperatures was particularly strong in tropical and sub-tropical regions like India.
- This could mean favourable conditions for the formation of cyclones in the Indian Ocean region as this is also the usual cyclone period.