RP378 Something in the Wind

 RP378 Something in the Wind

A vast brown cloud of smog, dust, and other pollutants hangs over the Indian subcontinent like a filthy smear of mud in the sky. It is the accumulation of decades of fossil-fuel abuse and vehicle emissions. In recent years, it has begun to affect the weather to such an extent that it endangers the lives of millions and can potentially cause billions of dollars' worth of damage.
A study has concluded that the so-called “Asian brown cloud” has directly increased the intensity of the area's tropical cyclones, particularly those forming over the Arabian Sea on India's west coast.
In India, harmful chemical emissions are now six times higher than they were in the 1950s. This increased concentration of harmful particles in the air acts like a sponge that absorbs the sun's rays, affecting the area in which the sun can reach and heat the surface of the sea. This has caused an atmospheric disturbance that has reduced the vertical wind shear in the area. Vertical wind shear is the difference in speed or direction between winds at different altitudes. High vertical wind shear is an important factor in weakening the formation of cyclones. As the wind shear decreases, cyclones in the area can strengthen to a degree that can cause major problems when they hit land.
Cyclones are caused by hot air rising from the ocean surface. Cold air rushes in to replace it and heats up, and this cycle eventually causes a violent circulation of wind and storms. Cyclones need to form vertically, so if the winds higher up in the atmosphere are traveling faster or in different directions to those in the lower atmosphere, this vertical formation will be disrupted, and the cyclone will disintegrate.
In the past, strong winds traveling in opposite directions (high vertical wind shear) would substantially reduce the frequency of cyclone formation in the Arabian Sea. However, with the brown cloud weakening the wind shear, cyclones in this area have grown in intensity. Cyclone Gomu, in 2007, was the strongest ever cyclone in the area, causing $4.4 billion worth of damages and killing 78 people. It was followed in 2010 by Cyclone Phet, which caused 47 deaths. To get these storms under control, India must tackle the causes of the brown cloud— which, in such a rapidly developing country, may be easier said than done.