Mapping the Highest Peak in the World | National Geographic
People know Mount Everest; it's the tallest mountain in the world. The big questions this expedition is answering is how climate change is happening in the high mountain regions. Maps are a critical tool for being able to measure the changes in the glacial extent.
[Music]
When we came over the crest of the hill and took a look at base camp the first time, I was like, "Oh my God, I can't believe we're gonna be trying to map."
[Music]
Mount Everest has been on the map since the mid 19th century, but it wasn't until about the 1920s when the British first started sending expeditions to the north side of Mount Everest through Tibet that we got large-scale detailed mapping. They were doing all their surveying using photographs and telescopic instruments to tie things together on a topographic map.
The transition from maps as paper products to maps as digital products has changed the way we work with geographic data. We're going to reconstruct how the glaciers have changed with the increased warming of the climate in this part of the world.
[Music]
"So at this angle or correct?"
"Yeah, whoa, crazy! That's one of the many apple hitches every day."
[Music]
People understand Everest as this big, beautiful mountain with a huge glacier running down it. If that glacier is gone, that's something that can't be brought back.
[Music]
As the glaciers melt, there's an initial increase in the amount of water available, and then eventually a decrease in the amount of water available to the rivers that come out of high mountain Asia. Hundreds of millions of people are going to be affected downstream.
[Music]
The Kumbu Glacier is the highest glacier in the world. It starts at about 8,000 meters on Mount Everest in what's called the accumulation zone. It's where all the snow falls and starts compressing into ice and flowing downhill. Base camp is a launching point for expeditions and climbers that are intending to summit Mount Everest. We wanted to map the full extent of that to capture the physical information but also to better understand how climate is modifying the glacier.
The work that Chris and I are doing here at base camp will be the most detailed map of the Kumbu Glacier that's ever been put together. The equipment that Chris and I are using is a very recently developed terrestrial-based lidar system. We're combining that with our helicopter-based lidar scanning using a very advanced device from Virtual Wonders, our partners on the helicopter scan.
The tools that we use for the terrestrial mapping are really three-fold. We're using lidar, which is a laser scanning tool. It shoots at two million points per second, taking individual measurements in a 360-degree sphere and measures everything that it can see. If you do that in enough places, you build an overall topographical model of whatever it is you're scanning.
Base camp is about three kilometers from one end to the other and a couple hundred meters wide, and it took us many stations to be able to collect all the data that we needed for all the tent areas and the glacial areas that are used for base camp.
Once you create a 3D model, you then need to what's called "skin the model" with very detailed imagery. We take pictures using DSLR photography. We're going to take high-resolution images to paste onto those measurements that the laser scanning provides.
So right now I'm taking three frames at a time, two-stop exposure bracket. We have bright, bright snow and really dark shadows. We need to be able to capture all of that information. If we were to lose highlights or lose shadows when we're building that environment that the model is going to go into, we just don't have that data. We're never capturing it again.
So we're doing our first overview pass with the drone, flying at about 50 meters. It'll fill any gaps that we might miss with lidar and with ground-based photographic work. This is a really difficult environment; drones really help us give the overall perspective on Everest base camp.
And the last thing that we're doing is taking a helicopter and attaching a lidar system and a video camera, and flying it up and down the Kumbu in a gridded pattern so that they can create a map of a much greater scale. The combination on the helicopter of the very advanced lidar and the photogrammetry will allow us to provide very detailed imagery on the surface of the model.
Once we're back in the lab, we can see all the different lidar data collected in one view. We've done a very, very detailed map of the Kumbu Glacier. This is base camp; the entirety of what you're seeing here is computer-generated.
Once you get the full resolution of the photography, it's going to be a virtual reality experience as if you were there looking at the tents at base camp. So if we take our 3D model, we can dive into it and start looking at more and more of the detail that's captured by the point cloud.
What we're going to be able to do is take this data and reconstruct how the glaciers have changed. One of the things that you can notice: the Kumbu Glacier has receded; it's probably dropped tens of meters in its elevation. So it's had an ice loss that's really pronounced for such a short time period.
This is a global issue that's going to have global ramifications. Every person in the world will be affected by this. One of the goals is to not just generate new science, but have the chance to build on the legacy of mapping this area to instill in people how important climate change is and to start working on addressing it now for a successful future.
[Music]