Strong monsoons reversing India’s 50-yr dry spell: Study

Indian summer monsoons have strengthened over the past 15 years, reversing a 50-year dry period during which northern and central India received relatively little rainfall, an MIT study has found.

Summer monsoons bring rainfall to the country each year between June and September.

Researchers found that since 2002 a drying trend has given way to a much wetter pattern, with stronger monsoons supplying much-needed rain, along with damaging floods, to the populous north central region of India.

A shift in India’s land and sea temperatures may partially explain this increase in monsoon rainfall, according to the study published in the journal Nature Climate Change.

Researchers note that starting in 2002, nearly the entire Indian subcontinent has experienced very strong warming, reaching between 0.1 and 1 degree Celsius per year. Meanwhile, a rise in temperatures over the Indian Ocean has slowed significantly.

According to Chien Wang, a senior research scientist at Massachusetts Institute of Technology (MIT) , this sharp gradient in temperatures - high over land, and low over surrounding waters - is a perfect recipe for whipping up stronger monsoons.

“Climatologically, India went through a sudden, drastic warming, while the Indian Ocean, which used to be warm, all of a sudden slowed its warming,” Wang said. “This may have been from a combination of natural variability and anthropogenic influences, and we are still trying to get to the bottom of the physical processes that caused this reversal,” he said.