There was a decrease in low cloud cover over most regions in India between 1961 and 201, says a study published in the Indian Meteorological Department journal Mausam.
The annual mean low cloud cover, which is responsible for most of the rainfall, shows significant decreasing trend of - 0.45 per cent per decade. The decline is particularly evident in monsoon season, with the cloud cover reducing by 1.22 per cent per decade. Monsoon is responsible for 70 per cent of India’s rainfall and snowfall.
The study also shows a decline in the number of rainy days in the monsoon season at a rate of 0.23 days every decade, which means that India has lost approximately one rainy day in the last 50 years. This is going by the IMD definition of a rainy day: when total precipitation is 2.5 mm or more.
The paper argues that the trend is a cause of “worry” and finds that while the number of rainy days are reducing, the total amount of rainfall does not show much change. This indicates shorter, heavier bursts of rain, which affects crops and result in runoffs, thereby not helping in groundwater recharge.