Monsooner or later

FARMERS throughout the ages have gleaned clues about the weather from the natural environment. Animal movements and the colour of the sky have been considered augurs. For one of the world’s most important weather events, India’s monsoon, forecasting methods are becoming rather more refined. About half of the country’s population—600m people—depend upon the rain it brings. Scientists want a better understanding of the processes by which the Indian Ocean interacts with the atmosphere, and underwater robots can help in their quest.

Monsoon climates typically have two distinct seasons: wet and dry. In India the rainy onslaught begins when moist air is carried northwards from the Indian Ocean during the summer. The winds transporting it come from an area of high atmospheric pressure in the southern Indian Ocean, and cross the equator before raging over the land. As the air gathers moisture during the journey, atmospheric convection forms storm clouds which arrive first in southern India around early June (as they did this year). The monsoon creeps north and west, showering Pakistan about a month later. By September it is in retreat and it is normally gone by December.

Information about when and where the monsoon will arrive is important for farmers, especially as almost two-thirds of India’s fields lack irrigation systems. The expected arrival of…Continue reading
Source: Economist