Project Introduction and Spring 2013 Snowpack

My PhD work focuses on physical controls on water storage and flux on Arctic hillslopes. I'm going to start sharing some of this work on here in order to practice communicating this information simply, clearly, and concisely. Here it goes.

In many parts of the Arctic, mean annual temperatures are below freezing. Over time, this has caused permafrost, permanently frozen ground, to develop. In my study area in the foothills of the Brooks Range, permafrost is continuous over large spatial areas and extends below ground to several hundred meters depth. However, something changes every summer: a thin upper layer of the permafrost, called the "active layer" warms and thaws as air temperatures soar above freezing for a few months- usually from late May to mid-September. This brief time window allows plants and other organisms to flourish on and in the unfrozen soils. Water too is able to flow into and out of the subsurface, carrying with it the substances that it dissolves such as mineral salts that weather out of the glacial till that makes up the hills and valleys, as well as the nutrients that feed biotic productivity. As the active layer deepens over the summer, the amount of time that water spends in the ground and the depths and subsurface materials that it can reach grow as well. This is one seasonal component to how water storage and flux change in the Arctic.

Water enters Arctic landscapes through rain and snow and leaves through runoff, shallow subsurface flow, sublimation, evaporation, and transpiration by organisms. Unlike many places on Earth, hardly any water is able to penetrate deeply into the ground to become part of a long-lasting groundwater reservoir because the permafrost prevents it. The difference in precipitation phase is another seasonal difference in water storage and flux in the Arctic, although the change is causes is stochastic. Over winter, snow accumulates and is stored on the surface in snowpack. A small portion sublimates, but most of the stored snow is lost during spring snowmelt. This is a rapid event, where the snowpack becomes isothermal then melts away, usually within the span of a week or even a few days. Most of the water quickly flows in the stream network, causing the stream water discharge to increase dramatically too. This flood pulse is the largest in most years, but sometimes summer rainstorms can cause even greater flood events.

One of the datasets that I collect is the amount of water stored in the snowpack on the hillslopes of my study area at the beginning of my field seasons. Here's the procedure:

Dig a snowpit to the base of the snowpack.

Describe the snow profile and identify layers in the snow for sampling.

Take samples of a known volume and weigh in the lab to determine density.

The amount of water stored in snowpack at the end of winter in 2013 was unusually large. For comparison, on average 12.9 cm of water were stored in snowpack in the spring each year in Upper Kuparuk River watershed in the mid-90s. From the 24 hillslope snowpits I dug, I measured an average of 23.6 cm of snow water equivalent. However, half the sampling locations I chose target features called water tracks that form in areas of convergent topography that drain the hillslopes. The other half are from non-water track locations. Comparing the two, I found that the water stored in the water track snowpack was significantly higher, likely because they form topographic lows and contain emergent shrubby vegetation that trap snow when the wind redistributes it over the winter.

Overall, the average snow water equivalent in the water track locations was ~28 cm, while the hillslope sites contained ~18 cm. This is still significantly greater than other years and makes for an exciting peek into what could happen in the future, when climate models predict that over winter Arctic snowfall will increase. I would also predict that ground temperatures, active layer thaw, and potentially water storage in the water track may be greater than the surrounding hillslope. Next, I need to investigate the timing of snowpack formation and melt at my different field sites. Since snow shields the ground from harsh winter air temperatures, both the timing and magnitude of snowpack are important factors in determining summer active layer conditions.

Mosquito Season

A personal perspective at one of our field sites yesterday.  It's pretty low quality video, but all those specks floating around and the ones that are all over my legs that you can't see are mosquitos.  This is lazy blogging.

It's been really dry here, dry enough to cause surface flow and ponded water at our water tracks to disappear almost entirely.  There is also a fire burning 50 miles to the west of Toolik Field Station, which I'm told is typical for this time of year in Fairbanks, but not this far north.

A Toolik Birthday

On Wednesday I turned a meager 24 years old.  Birthdays are becoming more routine as I get older, but at least they're always an acceptable reason for shirking normal work duties.  Unusual work duties, however, should not be shirked.  In my case, they include flying around in a helicopter for what really wasn't a good reason, but in was on our schedule, so what the hell.  The field station has two small Robinson helos (as they're called around here) for carrying heavy equipment to remote field sites in the summer and for times when speed is a necessary part of any research group's efforts.  The idea for us on Wednesday was to pick up a bunch of water samples that are being collected and stored automatically by a device called an ISCO at our six water tracks.  Unfortunately, they seem to be generally unreliable and each one only had a fraction of the water samples it was supposedly collecting.  But we went ahead and picked them up by helo anyway.  Here are some pictures:

The little helo I rode in.

The other helo that Margit was in, next to one of our water track sites.
The water track is highlighted by the dark willow vegetation that grows in many water tracks.

A view to the north along the Kuparuk River basin, criss-crossed by the pipeline and Dalton Highway.

Bird's-eye view of another of our water tracks on the west-facing hillslope.

After a short afternoon's work, we went back to Toolik for dinner, where my advisor and some friends surprised me with a homemade ice cream cake depicting a "Pyrenees" mountain scene, complete with gummy bear bears.

Amazing.

Then that evening I got to skip out on sample processing and went back to the Aufeis with a big group of people.  After three weeks of warm weather, the ice was beginning to break apart, and it was particularly beautiful in the evening light.

The ice field is breaking apart in the warm temperatures.

The groundwater that wells up to produce the Aufeis freezes very quickly forming these "candle" shards.

A waterfall where the stream is being diverted by the ice.

A tiny ecosystem flourishing on the dolomite valley walls.

Ah!  An ice cave monster!

Exploring a tunnel in the ice.

Jeb and Molly know that the candle ice makes for the best glass of whiskey on the rocks.

Sunday Hikes

Sundays are typically my one day off during the week.  To me, it seems like a waste to hang around camp  and sleep, so for the past two Sundays I've gone on hikes in and around the Brooks Range.  The first hike was to see some local aufeis before the seasons changed.  I went with Melissa, the kickass PolarTREC teacher who is on our research team for the first part of the summer.  For the second hike, I joined a bigger group headed to Atigun Falls, located just inside Arctic National Wildlife Refuge.

Cartwheeling towards the aufeis.

Mountain stream

On the ice

:3

The Dalton Highway is under construction so we had plenty of time to stare at the pipeline while waiting for the pilot car.

Atigun River crossing 2, where we left our trucks behind for the Atigun Falls hike.

The spooky Molar Mountain

Gorgeous glacially carved valley, with a skin of arctic tundra plant communities.

Marine stratigraphy

View of the falls from our lunch spot.

Mostly frozen this time of year.

Hiking back out to the valley.

The group.  Photo taken by Lisle Snyder.

Constructing Science

Over the last week, I've picked up a few skills I didn't expect to learn while out studying water flow paths in the Arctic.  I've spent much of my time constructing platforms for solar panels that power the electronic instruments we are deploying at our six field sites, as well as wiring and programming the electronics themselves.  Here are some of the steps involved:

Hauling scrap wood from the burn pile by the bonfire area.
Here, you can also see Toolik Lake still frozen, but the hillsides in the background are beginning to melt.

I learned to use a circular saw AND a table saw.

For my side of the project, the dataloggers (see four pictures down) are part of a thermocouple system, in which signals are sent down one wire to a temperature sensor, then come up a second wire with different material properties.  The signal is recorded by the datalogger and relates to temperature.  We have sensors at incremental depths underground in three wells, one inside the water track, one on the water track edge, and one outside the water track, at each of our six sites.  In this way, we can monitor how the temperature changes as the permafrost melt depth increases over the summer, and then freezes into the winter, re-thaws in the summer, etc.

I drilled a hole through a cooler to pull the wires that connect to the wells through.  The cooler houses the datalogger instrumentation and the battery, protecting them from snow and rain.

I had to strip all thirty wire pairs.  The wire is similar to thermostat wire.

Here's what I looked like for three hours.

Then I connected all the wires to the dataloggers.

Finally I hooked up the battery and the solar panel that will power it except through the sunless winter.  Hopefully it is working and recording data!  I'll go back and check soon.

Snow Days

I've arrived at Toolik Field Station, and really hit the ground running with fieldwork. My field season is divided into three parts, with lots of different tasks associated with each. There is the pre-snowmelt fieldwork, during snowmelt fieldwork, and post-snowmelt fieldwork. For at least one more day, it's the pre-snowmelt. However, the temperatures are soaring to the mid-40s during the day, so it's not going to last.  Here are some of the things we've been doing while we can:

The snow machines we use right now to get to our sites, which are right by the Alaska Pipeline.

My advisor, Sarah, taking snow depth measurements across one of our six water tracks.

Digging a snow pit to look at snow density differences.

Team members Sarah, Melissa, and Molly checking out the snow pit.

A look at the snow profile.  Snow depth here is about 40 cm.

We built greenhouses to accelerate melt, but they are much better at acting as sails.

... even though they are pretty big.

Soon I'll post pictures from around the field station itself.  I haven't even really been anywhere except my weatherport, the cafeteria, and our lab yet, but hopefully soon!  

Alaska!

This summer, I'm heading up to northern Alaska for three months of fieldwork for a two-year NSF-funded project with Dr. Sarah Godsey, a new faculty member at Idaho State University. We are investigating how climate influences the hydrology and biogeochemistry of Arctic hillslopes. I plan on detailing my adventures, life at Toolik Research Station, and our project in greater detail as I learn more about it too!

Right now, I'm enjoying my first and last night in the aptly named, but surprisingly flat Fairbanks, where the weather is a balmy 61 F. Tomorrow morning, I will take a truck 350 miles north to Toolik Lake, where the field station is. I got some last minute gear and snacks for the 8-10 hour drive at the lovely Fred Meyer, Alaska's equivalent of Meijer or Wal-Mart.

Today I got to see most of the country, flying from Raleigh, NC to Washington, DC to Seattle, WA to Fairbanks, AK.  Here are some views from along the way:

Kettle lakes and farmland of Minnesota

Puget Sound

Glaciers in the Cascades, near Juneau

St. Elias Range, home of Mount Logan (19,551 ft) and Mount St. Elias (18,008 ft),
the two highest peaks in Canada, and the second and third highest peaks in North America,
after Mount McKinley (20,327 ft). 

Close-up of a thrust sheet (horizontal fault trace) with spectacular lateral and transverse fluvial systems.

Bonus:  our research team also includes Melissa Barker, a teacher from CO, who is also keeping journals and answering questions through the PolarTREC program.  See her website here.