A recent IMD study has found that rain-bearing clouds have been thinning out across the country over the last 50 years. The study, published in the IMD journal Mausam, shows that between 1960 and 2010, annual mean low cloud cover (responsible for the bulk of the rainfall) over India has been decreasing by 0.45% per decade on an average.
According to the study, the number of rainy days is also declining during the monsoon season at an average rate of 0.23 days for every decade. This means that the country has lost approximately one rainy day over the last five decades. The study found that while the number of rainy days is decreasing, there is not much change in the total amount of rainfall. This shows a trend towards shorter, heavier bursts of rain.
That is bad news, because heavier raindrops can dislodge wheat and rice grains from their stalks while on the farm. It also means rainwater flows down a slope that much faster instead of percolating underground.
Meanwhile, a new NASA study has warned the amount of rainfall in the Earth’s tropical regions will significantly increase as the planet continues to warm. As per study rainfall is not related just to the clouds that are available to make rain but also to Earth’s “energy budget” — incoming energy from the Sun compared to outgoing heat energy. High-altitude tropical clouds trap heat in the atmosphere. If there are fewer of these clouds in the future, the tropical atmosphere will cool.