Physical geographer Walter Immerzeel will leave in May for a two-week expedition to the Langtang area in Nepal. There, he will work with Swiss and Nepalese scientists to install monitoring equipment. The monitoring data obtained will contribute to our understanding of the effects of climate change on the Himalayan glaciers and hydrology.
Immerzeel’s Veni study is part of a wider ICIMOD
research programme. ICIMOD is an international research and knowledge centre active in eight countries in the Hindu-Kush Himalayas and focusing on the effects of climate change on nature and the human population. Immerzeel will be travelling with scientists from ICIMOD and ETH
, the Swiss Federal Institute of Technology. They will visit various glaciers in the Langtang area, which is some 100 kilometres north of Kathmandu, to install equipment for use in monitoring precipitation and so on.
“I will focus primarily on measuring precipitation, initially throughout the valley and gradually moving to higher areas”, says Immerzeel. “Eventually we want to install a fairly sophisticated precipitation gauge on the Yala glacier at an altitude of some 5500 metres. For one thing, this gauge can very accurately measure the amount of precipitation; for another, it can measure the depth of the underlying snow cover with ultrasound. These two parameters will give us a good idea of the amount of precipitation at that altitude, which up to now we have known little about because nobody has ever taken these kinds of measurements at these altitudes before”.
The Pluvio 2, a high-precision precipitation gauge, will be used in combination with the SR50-L, an acoustic sensor that uses ultrasound to measure the depth of the snow cover.
Another group will study glaciers that are covered by a thick scree and are therefore very well insulated, which means they melt less rapidly. “This is also the first time a detailed study will be done in this area”. A third group wants to use isotope studies to study the composition of river waters at the foot of the mountains. “This will tell us the proportions of the melt-water, rain-water, groundwater and snow-water components in the river water”.
Immerzeel has previously carried out other hydrological studies in Asian mountain areas. “The models I worked on were similar, but on a much larger scale”. In 2010 he and two colleagues published a paper in Science on the five large drainage basins in Asia and the impact of climate change on, for instance, irrigation systems and food production.
Now his focus has shifted to a much smaller scale as very little is known about the actual underlying processes. As Immerzeel comments, “How much ice is melting? How fast is it melting? How fast is this changing? How much precipitation is actually coming down? The direct impact on the down-stream areas is still unclear, but we hope that will change soon”.
The lack of detailed precipitation measurements in this area attracted quite some media attention in late 2009, when a major error was discovered in the IPCC climate report on the Himalayan glaciers. The error was primarily caused by a lack of data and research in this field. Immerzeel’s study will therefore make an important contribution to remedying this.
Yala glacier at 5500 m altitude. Credits: Samjwal Bajrcharya.
Immerzeel will be in Nepal for two weeks, during which time he will spend three days camping at an altitude of 5500 metres. This will be both a logistic and a physical challenge. “Being in good physical shape is obviously essential. I’ve also previously lived in Nepal for a few years, and this time ICIMOD is taking care of the logistics”.
Immerzeel will write a blog, which will be published on the Faculty of Geosciences’ site after he returns.