Using UAVs to study the Lirung glacier in Nepal’s Langtang region, scientists from the University of Utrecht, the Netherlands, and the International Centre for Integrated Mountain Research, Kathmandu, have shown that glacial melt water generated under debris is only marginal to the total amount of water generated in the Lirung catchment.
The Lirung glacier being at a comparatively low elevation is sensitive to temperature changes and data from it can give clues to the fate of debris-covered Himalayan glaciers that are higher up, if global warming persists at projected rates, says the study, to be published in the July 2014 issue of Remote Sensing of Environment.
The UAVs collected data from sub-surface areas in the highly inaccessible, debris-covered Lirung glacier and provided imagery at a resolution superior to satellite-derived data, says Walter Immerzeel, lead author of the study and assistant professor at the department of physical geography, University of Utrecht.
“Within a glacier there are all kinds of voids and drainage channels. One plausible hypothesis is that the roof of such a void collapses causing a local depression,” explains Immerzeel. “This depression then fills up with water, which warms and accelerates the melt and which may result in a cliff on the edge.”
The higher melt rates in supra-glacial lakes (lakes or ponds formed on top of glaciers) and ice cliffs place emphasis on studying ‘englacial hydrology,’ or water dynamics and mass change in the internal regions of a glacier. In the future the melt rate may be connected to or created by englacial conduits and voids, the study says.
UAV technology increases the cost-effectiveness and accuracy of research as traditional methods of measuring melt rates are labour intensive, time consuming and difficult to carry out, especially on thick layers of debris.
“The Department for International Development has recently funded a project that supports our UAV research for the coming years,” informs Immerzeel. “Capacity building is an important component in this and we have graduate students joining us in field campaigns and we plan to organise a workshop in Kathmandu for relevant stakeholders.”
Kathmandu University’s glaciology programme is a likely beneficiary of the new technology. “We have plans to buy our own UAV and send students for field research,” says Rijan Bhakta Kayastha, coordinator of the Himalayan Cryosphere, Climate and Disaster Research Centre, Kathmandu University.
Link to the Remote Sensing of Environment paper
This article has been produced by SciDev.Net's South Asia desk.