UAV, a learning on a new technology on glacier monitoring

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The day when my supervisor asked me to join the  practical, field-based training on the use of Unmanned Aerial Vehicles (UAVs) over the Lirung glacier in Langtang, my thought was of Langtang valley in the aftermath of devastating earthquake in April 2015, which buried most of the valley. I have been to Langtang before in 2008 and 2009, and I was captivated by its serene beauty as an embodiment of nature’s perfection. Among the many memories, one that I cherished most is my friendship with a lady and her two years old son with whom I treasured each moment spent with them. 

I left Kathmandu along with rest of the team members on 2 October 2016. We were six members in total. We reached Syabru Bensi at around three in the afternoon and our expedition leader – Ngawang Dai from Glacier Safari Treks – had readied the afternoon snacks: pancake, peanut butter, tea and coffee. It was much welcome after the bumpy ride from Kathmandu. Syabru Bensi was the first stopover en route to our research site in Langtang and from there began our nights in the tent. My tent mate was Emmy Stigter, a PhD student from Netherlands. 

The next morning, we started our journey at 7 am to Sherpa Gau.  I have not been trekking for almost 6 years, and I felt little unprepared. Naturally, doubt and fear were constantly hovering over my head that maybe I could not keep up with rest of the team members. We had to ascend almost 1,100 m on the very first day to reach Sherpa Gau. Fortunately, on my way up, I met an old man, a retired geologist and 72 years old from London who was on his way to Ganga la Pass. Seeing him hiking up with a pair of trekking stick in his hands, equally supporting and balancing him in every step of his walk, was huge source of hope. He inspired me to embrace my faith that I can do it. I did not sense any exhaustion even when I reached Sherpa Gau.  

During the halt at Sherpa Gau, Dr Walter Immerzeel, an assistant professor at Utrecht University, the Netherlands, briefed me and my friends about the UAV flight plan and flight simulations for the Lirung glacier survey using the senseFly eMotion software that is packaged with the eBee. 

Dr Walter Immerzeel demonstrating flight planning at a trekking lodge in Sherpa Gau, 3 October 2016.
Photo: Dr Joseph Shea/ICIMOD

Our next stop was Ghoda Tabela. The weather offered cool breezes and made it easy for us to walk. Some moderate rain at night seemed to have made the path less dusty as well. On our way up, I saw several landslide trails and had to cross few in our path, careful not to make one misstep or I would have fallen straight into the Langtang River. 

Trail through the landslide, on the way to Ghoda Tabela, 4 October 2016
Photo: Finu Shrestha/ICIMOD

On the third day, we had to cross the Langtang Valley to reach Kyanjin Gompa, the site where the UAV training would take place.  As I drew closer to Langtang Village, I wished I could see the same beautiful village that existed before the earthquake -- happy kids running around, the villagers heartily welcoming us. But, ALAS!! It did not happen. Even though I had seen images of devastated valley in the news, I was not prepared to witness the actual scene. This was by far the most difficult phase of the trek; I could not believe the sight. The destruction was far more ruinous than what I had seen on TV. I crossed through three landslides, the largest one fell across where Langtang Village used to be. The old path had been swept away by landslides and a new one is being built to cross the village. It was definitely a heart rending and unpleasant walk. I kept thinking of that lady and her son as I crossed the village. 

Langtang Village where it used to be, before it got swapped away from the landslide, 5 October 2016
Photo: Finu Shrestha/ICIMOD

At 1:30 pm, we reached Kyanjin Gompa, had snack, and took rest. We were joined by two more colleagues -- Maxime and Jakob -- who had been in the Lirung glaciers for a week. We had another session of flight planning and simulation in the evening to prepare for our flight next day. On 6 October 2016, we headed for the Lirung glacier for the UAV flight. Joseph Shea, a visiting scientist with ICIMOD, led to us to the site located towards the right side of the lateral moraine of Lirung glacier. This site had been used previously for UAV flights. We made a UAV flight plan and launched the optical UAV flight twice to cover the debris part of the glacier. I was trained on how to make a flight plan, launch UAV, and monitor the progress of the flight through eMotion using area map and the flight monitoring tab. Then I learned how to import the images and flight log from the UAV to the laptop. 

Planning optical flight plan at Lirung glacier on 6 October 2016 (left) and launching the UAV on 7 October 2016 (right)
Photo: Dr Joseph Shea,/ICIMOD

After successful completion of UAV flights, we headed towards debris covered part of Lirung glacier where Maxime and Jakob had installed a meteorological station. I observed their field work and took some photos. On 7 October 2016, we conducted another optical and thermal UAV flight the same place. In the afternoon, I strolled around the Kyangin Gompa and interacted with local people, most of them were survivals of April 25 earthquake. In their own way, they seem optimistic about the future, their positivity rubbed off on me as well. The next day, I descended down from Kyanjin Gompa to Lama Hotel while others separated into two groups and headed to Ganga La Pass where ICIMOD and partners have installed snow-AMP stations. The other group headed to Langshisha for more UAV flights. I reached Syabru Bensi at around 11 am, in the real world, and a jeep was waiting to take me to Kathmandu. For me, this journey represented a time for self-reflection and an outstanding opportunity to learn how to use UAV technology.

Standing in front of the Lirung glacier
Photo: Emmy Stigter, Utrecht University, Netherlands

Finu Shrestha


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