The snowfall and rain in the Himalayas is about twice as high as commonly assumed, a new research said.
The research in the Indus basin by scientists from Utrecht University, FutureWater and the International Centre for Integrated Mountain Development (ICIMOD) led to the findings important for water management and climate change impact assessments.
The upper Indus is supposedly very dry, yet the largest glaciers outside the polar regions are located in that area and seemed contradicting. It gave us the idea for the study, said lead author Walter Immerzeel.
"We calculated how much precipitation is required to sustain those large glaciers and the results were spectacular.
In the most extreme case, a more than tenfold amount of snow is required than what was previously thought," he said.
In order to derive this information, the researchers combined satellite observations, a computer model and observations from the ground.
The Himalayas and adjacent mountain ranges are an important source of water for more than 25 percent of the global population.
However, it was unknown how much snow and rain falls in those vast mountain ranges, because of the lack of observations and the inaccessibility of the terrain.
Understanding how much water is available in the source areas of Asia's large rivers is of crucial importance. The rivers confirm the findings.
"In the absence of snow and rain measurements at high altitude in the Indus, we needed another way to confirm our findings," Immerzeel said in an email to IANS.
"We use observations of river flow and the results confirmed that the amount of water in the rivers can only be explained if the amount of snow and rain is as high as we estimated," he said.
The Indus basin, which stretches over 1.1 million sq km and is shared by Afghanistan, China, India and Pakistan, with the upper portion resting in the Hindu Kush, Karakorum and Himalayan ranges, irrigation scheme is the largest in the world and it is fed primarily by melt water.
"Since so much of the food production in the Indus depends on glaciers and snow, this shows again how sensitive this area is to climate change," said Marc Bierkens, professor of Hydrology at Utrecht University.
"Our findings will have important bearing on climate change impact studies and water management in this important trans-boundary river basin," he said.
The research titled 'Reconciling high-altitude precipitation in the upper Indus basin with glacier mass balances and runoff'.
While Utrecht University is the Netherlands based, FutureWater is a research organisation that works throughout the world, and Kathmandu-headquartered ICIMOD is a regional inter-governmental centre and works in the Hindu Kush-Himalayan region.