GS Paper 1:
Topics Covered: Important Geophysical phenomena such as earthquakes, Tsunami, Volcanic activity, cyclone etc.
An analysis of past data of cyclones over North Indian Ocean (Bay of Bengal and Arabian Sea) during the period from 1891 to 2020 indicates that:
- The frequency of “very severe cyclonic storms” has increased in recent years over the Arabian Sea. However, this has not measurably increased the threat to India’s western coast, as most of these cyclones were making landfall in Oman and Yemen.
- The Eastern Coast remained far more vulnerable to “Extremely Severe Cyclones” than the Western coast, but there was nevertheless “no significant trend” in the frequency of Extremely Severe Cyclonic Storms (ESCS).
- The number of deaths due to cyclones has decreased significantly, as a result of the improvement in the early warning skill of the India Meteorological Department (IMD) under the Ministry of Earth Sciences (MoES).
- The effective mitigation measures and response actions by the National Disaster Management Authority (NDMA) and Ministry of Home Affairs (MHA) have also improved.
- Surface temperatures in the Arabian Sea have increased rapidly during the past century due to global warming. Temp. Now is 1.2–1.4 °C higher than the temperature witnessed four decades ago. These warmer temperatures support active convection, heavy rainfall, and intense cyclones.
- The rising temperature is also enabling the Arabian Sea to supply ample energy for the intensification of cyclones.
- The Arabian Sea is also providing conducive wind shear for cyclones. For instance, a higher level easterly wind drove the depression of Cyclone Ockhi from the Bay of Bengal to the Arabian Sea.
Naming of Cyclones:
Know how Cyclones are named here.
Do you know the differences between Supercell and Mesocylone? Reference.
Did you know that a very severe cyclone is defined as one with wind speeds touching 220 kmph? It is the fourth highest category of cyclones, just below “Extremely Severe Cyclones”.
- Factors responsible for the genesis of cyclones.
- Naming of cyclones in various regions of the world.
- Why are there more cyclones in Eastern coast of India?
- What is coriolis force?
- What is the latent heat of condensation?
Discuss the factors responsible for the formation of tropical cyclones.
Sources: the Hindu.