The International Centre for Integrated Mountain Development (ICIMOD) is exploring the use of unmanned aerial vehicles (UAVs) to better understand change processes of mountain glaciers, and use appropriate volume estimation methods for different types of mountain glaciers.
UAV flights were carried out in the second week of November 2016 over Gangapurna and Ponker glaciers, and a lake area in Manang Valley, Nepal. Flights were carried out by a team of remote sensing and glaciology researchers from ICIMOD in collaboration with Kathmandu University.
This approach – of using a remote sensing technique with field validation – is an attempt to properly understand various stages of changes in glaciers, as different types of volume estimation methods may be necessary for studying different types of glaciers. Such methods increase the accuracy of glacier ice volume measurements as well.
The team successfully collected high resolution stereo-pair images, and generated Digital Elevation Models (DEMs) to understand the present scenario of glaciers, and their morphological features.
“This mission helped our team develop confidence in handling UAVs at a distance of 3 km from the landing/takeoff site, and an elevation of 700 m from the ground,” said Samjwal Bajracharya, ICIMOD’s remote sensing specialist, who was leading the team in the field. “We can now explore the use of UAVs in other areas, including flood- and landslide- hit regions, and areas with forest cover. Agriculture monitoring applications can also be explored,” he added.
A total of five UAV flights were carried out, two over the Gangapurna glacier and lake area, and three over the Ponker glacier area. Multiple additional field expeditions will be required for acquiring sets of photographs that can be used for thickness change analysis, and the monitoring of morphological changes in glaciers and their surroundings. Several images of areas that will be used for morphological analysis and DEM generation were collected during the UAV flights in November. Data from the field expedition will be used in morphological classification, and estimation of water reserves in Himalayan catchments in Nepal.
The data generated can be used by professionals and researchers engaged in glacier mapping and monitoring for water resources management. It will support snow and glacier melt monitoring, and the development of climate change scenarios for the HKH.
In terms of glacier mapping and monitoring, ICIMOD has been working with partner institutes in the region to build a regional database of HKH glaciers and glacial lakes since 1999. The centre’s recent work on mapping glaciers and glacial lakes includes the use of semi-automatic delineations from satellite images. However, good quality, high resolution satellite images are difficult to acquire, and are only available on Google Earth. These images are insufficient and inefficient for use in a detailed study of the dynamics of glacier morphology.
A flight path captured in photographs by eBee in the Gangapurna glacier and lake area