This Trip Comes to a Successful Ending…

Cathy left earlier in the week, but Go and I continue to conduct snow surveys across our four research sites on the Barrow Environmental Observatory (BEO). Go learned the protocol for these surveys from Cathy and, as a result, is quite efficient at gathering snow depth measurements from 300 or more low- and high-center polygon locations. He is equally efficient in collecting snow samples from which we will calculate water equivalents. Both of these measurements and their changes over time will be useful to our modelers, who will use this information to incorporate snow accumulation and resulting water discharge into their high resolution landscape models where we are concerned with microtopography and the contribution of different types of polygons to hydrology. While Go was busy collecting this information I had the opportunity to grab several replicated snow and surface water samples for Baohua Gu (ORNL), one of our team’s geochemists. This was not too difficult. However, we had hoped to get pore water samples as well, but the depth of the active layer is not sufficient to insert sample collection tubes into the soil. I will do this again in mid-summer when the soil has thawed and it is easier to collect pore water for analysis.

 

 

 

In between our other activities, I had the opportunity to troubleshoot some communication issues with the energy tram and our micrometeorology tower that includes CO₂ and CH₄ flux measurement capabilities. It has been a few years since I last worked with data transmission systems, but Dave and Bryan spent a couple hours on the telephone with me and we sorted out the troubles. It turns out that while the two systems were designed as standalone units, interference was generated between the two communication links. This introduced sporadic problems, mostly for the eddy covariance tower. By the end of the day, however, both systems were working as designed and data were being collected, stored, and transmitted to the University of Nebraska and LBNL.

 

 

Given that it was my last day in the field I took a break, propped my feet up on my backpack, and gazed off some 1300 miles towards the North Pole. Three years ago when our team first visited this area it seemed like a strange and foreign, albeit exciting environment. Now, our team seems quite comfortable coming and going from the field site, and living for weeks at a time in Barrow. We all agree that the research we are doing – that of conducting field and laboratory studies to improve climate models – is a worthwhile and challenging endeavor. Regardless of your scientific discipline, and we have scientists studying everything from to genomics to geophysics, the North Slope of Alaska is a great place to be conducting research.

 

Finally, and before heading to the airport, Go and I wanted to stop by the Barrow Arctic Research Center (BARC) where we are fortunate to have a modern laboratory space to use in our science. We had asked Karl Newyear, Chief Scientist for UMIAQ, to meet us there so we could check out a freezer that had been purchased and delivered to the BARC in May. Karl was able to locate a secure space for the freezer. It is already being put to good use as it was full of permafrost cores from our sampling trip in April and early May. These cores, many of them extending to 2 meters into the subsurface, were collected by our geophysics colleagues from LBNL and will be shipped to California in the near future for analysis.

 

After saying goodbye to Karl, I had just enough time to take a shower, toss my field clothes into my duffel bag, and head for the airport. Check-in and boarding is fairly painless in Barrow and within 30 minutes of the flight, I was taking off for Anchorage to connecting flights in Chicago and then to Knoxville. It was a successful trip with all signs pointing to a productive field season. I will return later in July when our plant physiology team including Alistair Rogers and Shawn Serbin from Brookhaven National Laboratory (BNL) should be in Barrow conducting photosynthesis measurements on tundra vegetation. I am already looking forward to that…

 

 

High, Dry, and Free of Snow…

Two years ago the NGEE Arctic team established our research sites on the Barrow Environmental Observatory (BEO). We designed our studies around geomorphological features including thaw lakes, drained thaw lake basins, and polygons of which there are three types; low-, flat-, and high-centered polygons. The various types of polygons are of interest to our team because they have what we believe to be marked differences in CO₂ and CH₄ flux, temperature, and hydrology. Scientists on our team are gathering data and developing models to test this possibility and will then use those models to examine what a change from low- to high-centered polygons due to permafrost thaw might mean to carbon cycle and energy balance processes over the next century.

We have already made great strides in addressing how landscape evolution and the thaw lake cycle will potentially impact CO₂ and CH₄ fluxes, with an eye towards getting this information into high-resolution climate models. It has been interesting this week to walk the BEO and, when time permits, to consider how snowmelt and associated processes might differ across the polygons that we are studying. What I have observed is that the tops of the high-centered polygons do not have very deep layers of snow and the snow that accumulates on them during the long winter seems to melt first before melting on any of the other features in the landscape.

 

Scientists including Margaret Torn, Bryan Curtis, Melanie Hahn, and others have not yet summarized all of their chamber-based measurements of CO₂ and CH₄ flux from previous years at this point, so I cannot be overly quantitative about this observation. However, looking at our field sites, especially those in and among high-centered polygons, I can imagine that the growing season is longer, soils are warmer, albeit possibly dryer, and thus environmental conditions may result in different rates and seasonal magnitudes of CO₂ and CH₄ flux from these features. If so, then we need to incorporate this fine-scale information into our models.

Getting a Feel for Changing Snow Conditions…

Each of the last three days I have walked the 2 kilometers from the road to our field sites on the Barrow Environmental Observatory (BEO). Although snowmelt has been slow to develop, I have noticed that the snow conditions are changing. Those who spend time outdoors in the late winter and early spring know the challenge that comes from walking across snow and constantly breaking through that surface crust, only to drop deeper into the underlying snow. That is what it was like today and we are beginning to see signs of pending snowmelt.

 

Cathy and Go have been characterizing snow conditions all week. Their research began with surveys of snow depth and has recently expanded to include measurements of snow density and snow water equivalent. A series of transects were established and Cathy and Go walk together every day collecting information that will help us to understand the timing and quantity of water distributed across the landscape as the snow melts. Their measurements begin with inserting a plastic tube of known diameter into the snow. Cathy records snow depth in centimeters while Go gently digs down to the base of the cylinder and lifts the tube, now full of snow, out of the hole. The snow in the tube is transferred to a plastic bag and then quickly weighed. A simple calculation allows the volume of snow to be estimated along with the weight of water contained within that volume, and based on those two pieces of information, snow density and snow water content can be calculated. Such information will be useful as we study the relationships between snowmelt and lateral runoff during this dynamic part of the season.

 

 

The measurements that Cathy and Go are making suggest that the density and water content of snow is increasing with each day. We see some signs of standing water on the BEO, but no significant lateral runoff yet. It is only a matter of time.

 

 

Nothing Stands Between Me and Barrow Except Time…

My trips to Alaska are normally uneventful with nothing but time usually standing between me and my final destination of Barrow. That was not to be the case on this trip as I had problems almost right from the beginning. Flight delays caused me to miss my connections in Chicago, which made my arrival into Anchorage too late to catch my flight to Barrow. That resulted in an unexpected night stay in Anchorage and then an early morning flight to the North Slope via Fairbanks, Prudhoe Bay, and finally Barrow.

The good news is that I was working in the field with Cathy, Go, Andy, and Tristan by noon. When I arrived at our sites on the BEO, Cathy and Go were tracing a network of troughs across the tundra. These will be the preferential paths for lateral flow of water once snowmelt occurs.

I also had the opportunity to quickly look into the newly-built tram system that was installed just last month by Bryan, Keith, and Paul. These three did an excellent job of getting the tram bases and support rails constructed prior to snowmelt, and the instrument package initially tested. The sensors will all be used to gather data on energy balance along the 60-m transect and other periodic measurements will be collected to evaluate carbon cycle processes and soil moisture patterns throughout the season. There are already patches of vegetation along the transect, so these changes should be increasingly captured by our measurements. Our modelers expressed an interest in the spatial and temporal data for the design and evaluation of their fine-scale models. It should be interesting to track insights that come from this system in the coming months.

 

Tomorrow Cathy, Go, Andy, Tristan, and I will continue to prepare for the pending snowmelt. It is lagging behind what we have seen the last two years and our hydrologists are anxious to see flowing water. Area temperatures are forecast to be warmer in the next few days, so we will see if this translates into marked changes in snow characteristics and snowmelt.

Hydrologists Wait for Flowing Water…

NGEE Arctic scientists have been busy throughout the months of April and May conducting geophysical campaigns, snow surveys, and sampling permafrost cores with hydraulic drill rigs at our field sites outside Barrow, Alaska. Cold temperatures, ample snowpack, and frozen ground make April and May an ideal time for these activities. June marks the beginning of spring on the North Slope of Alaska and this means warmer temperatures and pending snowmelt. This is the time when our hydrologists travel to Barrow and begin their flurry of measurements. Cathy Wilson and Marvin Gard from Los Alamos National Laboratory (LANL) and Go Iwahana from the University of Alaska Fairbanks (UAF) arrived in Barrow last week, anticipating an early snowmelt. Temperatures hovering at 32^oF and signs of melting snow suggested this might be the case, but just as quickly as our team arrived in Barrow the temperatures dipped back into the low 20’s and snow began to fall. High winds created a few days with white out conditions so our science has been on hold; our hydrologists are now waiting…for water.



Photo courtesy Craig Ulrich (LBNL).



My travels to Barrow begin Monday. I plan to join Cathy, Marv, and Go in hopes of warmer temperatures on Tuesday when we will begin measurements of snowpack, snow water equivalents, and start tracking lateral distribution of water across the Barrow Environmental Observatory (BEO) where are field sites are located. Andy and Tristan (UAF) will also be joining us on Tuesday, along with Anna Liljedahl, also UAF, later in the week. Together the seven of us will be gathering data to better understand and describe hydrologic processes in permafrost regions. Insights from our work will be used to improve how we represent water-related processes in models, especially climate models.

This will be a busy time for members of our field research team so stay tuned…