Part of: Prelims and Mains GS – III – Disaster and disaster management
In news: The India Meteorological Department (IMD) noted that a well-marked low-pressure area currently lies over the southeast Bay of Bengal, and it is expected to move west northwestwards and intensify into a depression during the next 12 hours.
The depression will then moves northwestwards and turn into a cyclonic storm over the central parts of Bay of Bengal in the subsequent 24 hours.
This cyclonic storm – known as cyclone Jawad — is expected to reach the coast of Andhra Pradesh and Odisha on December 4 mornings.
Cyclones:
Tropical cyclones are violent storms that originate over oceans, in tropical areas and move over to coastal areas bringing about large scale destruction caused by violent winds very heavy rainfall and storm surges.
A cyclone consists of a low-pressure area with high pressure all around.
Tropical cyclones are generated in regions of near zero horizontal temperature gradient. Tropical cyclones require very low values of tropospheric vertical shear in order to form and grow.
They have large diameters.
How are cyclones forecast?
Over the years, India’s ability to track the formation of cyclones has improved significantly.
Radar Network: There is a network of 21 doppler weather radars (DWR) in the country (12 along the coast). Depending on where a storm is forming, these radars send pulses of radio waves to gauge the size as well as the speed at which water droplets are moving.
Real time feedback: The earlier generation of radars was unable to track such progress in real time, but with DWRs, now the base standard of weather radars, it is usually possible to detect a potential storm at least four-five days in advance.
International Collaborations: The IMD also collaborates with similar international networks, such as the Japan Meteorological Agency, the U.S. National Hurricane Center, and the U.S. Central Pacific Hurricane Center, and these bodies constantly send warnings and forecasts about changes in the ocean weather.
Technologies that supplement radars: The near ubiquity of ocean-buoys that track changes in ocean sea surface temperatures as well as dedicated meteorological satellites improve the odds of early detection
