A stroll over a ridge and then several hours* walking over snow, shuffling over a slippery frozen lake, and clambering through loose rock and debris brought us to Changri Nup base camp, at 5358 m (17,580 ft).
Changri Nup base camp. The two big mountains in the background are Everest (Chomolungma) and Nuptse on the left and right, respectively.
* The porters and Pyramid staff do it in 2.5 hours. From personal experience, I can report that with a blood oxygen level of <=57%, it takes more like 4.5 hours. It’s only a few kilometers, but the loose, rocky terrain makes it slow going. There are cairns marking the generally advised direction, but there is nothing resembling a trail for most of the way.
First I’m going to describe the science we did there and then mention some of the details about field logistics.
The field team was comprised of 10 project scientists and one Pyramid science tech; it was originally supposed to be 11, but ICIMOD glaciologist Dr. Joe Shea did not come due to a last-minute denial of a UAV permit. In addition to Mike, Josh, and me, the fieldteam was comprised of 2 Nepal-based researchers (ICIMOD and NAST), 2 France-based researchers, a French meteorological station specialist, a French PhD Student, and a Nepali MS student. Our collective aims included monitoring weather, tracking speed and lowering of the glacier, quantifying melt, and understanding the physical properties of the debris.
The last item is where my work fits in: I’m interested in using satellite imagery to discern debris thickness from temperature, making sure that the derived thickness is correct by comparing it to field measurements, and also modeling how the debris layer transfers heat to the ice surface. Towards these aims, my fieldwork on Changri Nup had three components.
1. Satellite: Last summer, I applied for a NASA-operated satellite to take pictures of Changri Nup while we were in the field. In order to make sure I apply the appropriate offset (if any) to temperature data from space, I needed to measure actual temperatures during the two satellite flyovers. I did this with 20 temperature sensors as well as images with a thermal camera.
A temperature sensor, with a pen for scale. We put half in direct sunlight and half shaded so that we could also determine whether the temperatures were affected by the sun heating up the sensors’ containers. The actual sensors are inside the black moisture-sealed capsule and look like this. These are the sensors Josh and I programmed while at the Pyramid Research Station, two days before the first satellite flyover.
2. Debris properties: I work on calculating glacier melt from energy models, which require all of the energy inputs (and outputs) for the glacier system. Some, like energy from sunlight or precipitation, are easy and directly measurable. The hardest one to calculate accurately is the heat that is transferred through this debris layer by conduction. Measuring how the temperature and humidity changes with depth and with time will help us understand how to model this well.
The temperature and humidity sensors on a bamboo stake before burial. The cross bars are to keep the bamboo vertical (hopefully) for the next year.
Buried in 1 m of debris, after a day of digging, with a trekking pole for scale.
3. Finally, I wanted to measure debris thickness in the field so that we understand the satellite images better – and because I wanted to see if a relatively underutilized method (ground penetrating radar, GPR) could be useful for studying debris covered glaciers. Getting the amount of GPR data I had hoped for proved to be difficult; from distant aerial photographs, I was not prepared for the size of the debris, the roughness of the terrain, and the juxtaposition of fine debris, car-sized boulders, and deep glacial lakes.
MS student Sonam for scale, with debris cover where we placed the 1-meter profile of temperature and humidity sensors.
Debris cover in the center of the glacier, with Josh for scale.
The terrain was difficult to walk on—not to mention operating and dragging geophysical equipment over! Still, we did manage to find two flat spots: one close to the top of the debris-covered area (high on the glacier, at > 18,000 ft) and one closer to camp, on the side of the glacier. We performed comprehensive surveys on each:
Josh marking the length of a transect for GPR.
I’m excited to analyze this data to see if the method worked, even if we were unable to drag the sled (er, rather, baby baths) all the way across and down the glacier.
Since I’m often asked questions about field logistics, I figured I’d provide a few details here:
How did the gear arrive?
A lot of it was carried by these guys:
(I can’t remember the yaks’ names, sadly).
and the remaining parts were carried directly by porters, who strap loads together and carry the weight on their heads and backs. Seeing porters on the trail was a constant reminder that my 40-lb pack was NOT heavy. The Khumbu valley hosts a permanent population in several villages, as well as a booming tourist industry. But everything—from restaurant food to safe drinking water, building materials to outdoor shop gear—has to be carried by people or yaks. Donkeys are used at lower elevations, too. On my way down, I met a man much shorter than myself carrying 4 doors on his back…and he was a 3-day walk from the start of the tail.
What did we eat?
In camp, we were supported by porters, including a cook. At 6:45 every morning, porters brought us black tea in our tents to wake us up (I have never experienced this in fieldwork before!) Breakfast was served at 7 am sharp; we had rice pudding, cinnabuns, pancakes, or chapatti bread, usually with 1 scrambled or hard-boiled egg per person. We would leave camp for the glacier (30 min walk) by 8 am at the latest, taking our packed lunches of fresh-baked Nepali bread, crackers, nak cheese, mango juice (really half-frozen slush), and Snickers or Twix.
How cold was it?
When the sun was shining, it was pretty warm, around freezing and, unless the wind was blowing, quite comfortable. But when the sun went down, it got cold. Nighttime was around -20C. This was the first time for me in 3.5 years that I’d seen the sun set during fieldwork or had to think about the fact that daytime and nighttime temperatures could differ dramatically. (Thankfully, I remembered to pack a headlamp!) I didn’t realize what a luxury it was to have 24 hour sunlight, both in terms of safety and in terms of science, in Greenland and Antarctica. Because the mountains are so steep and because we were working in winter to avoid the monsoon, we stopped receiving direct sunlight around 3 pm. At 4:30 it was really cold, and by 5:30 it was completely dark. Most of the team would return to camp around 5 and huddle in the kitchen tent over black tea and cookies until dinner at 6:30. Dinner was always prawn crackers and soup appetizers followed by something Nepali or Italian: the traditional dal bhat, pasta (usually with nak cheese), or pizza for the main with the occasional side of “salad” (peas or cauliflower in a cream sauce). Dinner on thanksgiving consisted of popcorn, onion soup, pasta, and cauliflower. Dinner on the last night was particularly special; the porters hiked a 10-hour round trip to buy fresh yak meat and make us yak curry and dal bhat!
What makes up the base camp?
We slept two to a tent for warmth; camp was comprised of personal tents, a cooktent, a dining tent, and a toilet tent. I was quite grateful for the porters who had most of this set up when we arrived! Being equatorward of the Arctic/Antarctic circles meant shorter work days and cold nights…AND some of the most amazing sunsets I’ve ever seen. Every day we’d walk back to basecamp with a backdrop of the sun setting behind Mt. Everest and Mt. Nuptse. And, no, I’m not sure I was ever really able to comprehend the scale or beauty of these mountains, although I was constantly feeling fortunate for the opportunity to work in them on what I believe is going to prove to be exciting and important work.
Sunset with cook tent, Everest, and Nuptse.
Thanks for your interest; please feel free to send questions if you have any!