Low-Pressure System In Arabian Sea Set To Intensify Into Cyclonic Storm ‘Tej’

Low-Pressure System In Arabian Sea Set To Intensify Into Cyclonic Storm ‘Tej’

Subject: Geography

Section: Physical geography

Context:

A low-pressure area over the southeast and the adjoining southwest Arabian Sea has developed into a depression and is expected to intensify into a cyclonic storm by October 21 morning, the India Meteorological Department (IMD) said today.

How a Tropical Cyclone is Formed?

• Tropical Cyclones are a weather phenomenon.
• A tropical cyclone is formed only over warm ocean waters near the equator.
• Warm, moist air rises up and away from the ocean surface, creating an area of low pressure.
• It causes the air from surrounding areas with higher pressure to move towards the low-pressure area.
• This leads to warming up of air and causes it to rise above.
• As the air rises & cools, the water in the air forms clouds.
• This complete system of clouds and wind spins & grows, along with the ocean’s heat.
• As the wind rotation speed increases, an eye gets formed in the middle.

Characteristics of a Tropical Cyclone

• The center of a cyclone is very calm and clear with very low air pressure.
• The average speed is 120 kmph.
• They have closed isobars which leads to greater velocity.
• Isobars are imaginary lines on a weather map that connect locations with equal atmospheric pressure.
• They develop over oceans and sea only.
• They move from east to west under the influence of trade winds.
• They are seasonal in nature.

How are Cyclones Classified?

• Cyclones are classified on the basis of wind speed by the Indian Meteorological Department (IMD):
• Depression: Wind speeds of between 31–49 km/h
• Deep Depression: Between 50-61 km/h
• Cyclonic Storm: Between 62–88 km/h
• Severe Cyclonic Storm: Between 89-117 Km/h
• Very Severe Cyclonic Storm: Between 118-166 Km/h
• Extremely Severe Cyclonic Storm: Between 166-221 Km/h
• Super Cyclonic Storm: Above 222 Km/h

How are Tropical Cyclones Named?

• There are five tropical cyclone regional bodies in the world:
• ESCAP/WMO Typhoon Committee,
• WMO/ESCAP Panel on Tropical Cyclones,
• RA I Tropical Cyclone Committee,
• RA IV Hurricane Committee,
• RA V Tropical Cyclone Committee.

WMO/ESCAP Panel on Tropical Cyclones is responsible for naming of cyclones in the Indian Ocean.

About WMO/ESCAP Panel

• It is an intergovernmental regional body jointly established by the World Meteorological Organization (WMO) and the United Nations Economic and Social Commission for Asia-Pacific (ESCAP) in 1972.

Objective:

• To promote measures to improve tropical cyclone warning systems in the Bay of Bengal and the Arabian Sea region.
• It comprises thirteen countries in the region – Bangladesh, India, Iran, Maldives, Myanmar, Oman, Pakistan, Qatar, Saudi Arabia, Sri Lanka, Thailand, United Arab Emirates, Yemen.
• They contribute to a set of names which are assigned sequentially whenever a cyclonic storm develops.