Prelims: Indian Geography | General issues on Environmental ecology
Why in News?
The intense storm recently hit Delhi looked like a crescent or an archer’s bow, in technical terms, such presentations of storms are called “bow echoes”.
A bow echo is essentially a line of storms, also called a squall line, on the radar that looks like a bow.
Term coined by - Ted Fujita, a Japanese American meteorologist known for developing the scale to classify tornadoesin the 1970s.
This squall line can sometimes be embedded in a larger squall line.
A bow echo can extend from 20 km to 100 km, and last between 3 and 6 hours.
Formation - When rain-cooled air comes down to the ground, and spreads out horizontally.
As this happens, a boundary called the gust front is created between the rain-cooled air and warm-moist air on the surface.
This front pushes up the warm-moist air into the atmosphere, which forms new thunderstorms.
These new thunderstorms produce more rain, thereby creating more rain-cooled air, which helps the gust front to maintain its strength.
As this process keeps repeating itself, there comes a point when there is an inflow of air on the trailing side of the line of storms and bends it like an archer’s bow.
The cycle lasts as long as new thunderstorms keep forming at the front, helping the system grow and move forward with strong winds.
Bow echoes are not a new phenomenon. In 2022, a bow echo was formed over Delhi and Noida. However, it was short-lived, lasting for an hour, and produced winds of up to 100 kmph.
Such a squall line was observed during thunderstorm activity in Odisha earlier this month.
