Sunday, May 13, 2012

Hitting the Tundra

It has been cloudy in the last couple of days. Jonathan Ajo-Franklin from LBNL joined the spirited gang of Arctic geophysicists and with his arrival the seismic acquisition has started. Surely the lemmings and the inhabitants of the quiet tundra have noticed our new activity.
Alessio hits the ground with the sledgehammer while Jonathan carefully observes the seismic wave being recorded by the geophones. Glen, our great bear guard, learns about seismic too. 
 For the entire day we have been repeatedly hitting the tundra with a 30 lbs sledgehammer. Today, we swung the sledgehammer approximately 600 times to introduce seismic energy into the subsurface. The seismic energy traveled in the frozen ground and was recorded by a number of little geophones, which were accurately buried within the snowpack.We are carrying out both surface refraction and MASW (multi-channel analysis of surface waves) methods.
It is time to move the seismic line. The team digs the geophones out from the snowpack. 
 The seismic experiment will allow us to measure the seismic velocities within the permafrost. This is a precious information that can be used to discern the physical properties of the subsurface. As with all the other methods we have applied in this campaign, it allows us to interrogate the  permafrost without really directly touching it.

We have now two more days left until the end of this very intensive geophysical campaign in which we collected a tremendous amount of information.
We have all learned a lot  - about geophysics, about the tundra, about the North, and about each other. 
John patiently completes the GPR survey while the rest of the team focuses on the seismic and the electromagnetic methods.
Written by Alessio Gusmeroli (UAF) 

Saturday, May 12, 2012

Reflections on the Tundra

Written by Alessio Gusmeroli (UAF)

It is really flat up here. No matter where you look, there are no hills and there are no mountains. The topography is as boring as it gets. This is noticeable if you are a glaciologist (as am I) - used to working narrow valley field sites that are filled by ice and surrounded by rugged peaks and spectacular mountains.
The flat Arctic Coastal Plain
The glory of the Arctic coastal plain does not come right away. It comes with careful inspection. One must stop, listen and look very carefully. If you do that, you hear the sound of the wind, you hear a myriad of snow granules constantly in motion. You notice the role of the wind in creating snow sculptures on the surface. You see beautiful moving snow dunes that resemble their sand relatives. 

The way snow fills the coastal plain is indeed one of the first things we have been learning about in this fieldwork. The presence of snow and the possibility to use snow machines is facilitating all our field operations. With Susan, John, Baptiste and Craig we have been running a variety of "motorized" geophysical experiments, in which the geophysical device is towed across the tundra by the snowmachine. 

The ground penetrating radar, for example is giving us a good idea on what lies beneath the snow pack. First, we see that the snowpack is thicker above ground depressions (i.e., polygonal troughs); second, based on the reflections in the radar data we see that the permafrost that lies at depths greater than 1 m is anything but homogeneous. We have noticed a number of reflectors, likely part of a network of ice wedges and intervening layers. We will be learning a lot more about the deeper ground ice and its relationship to active layer and snow variability once we assemble and jointly interpret the entire datasets. 

Undertaking geophysical fieldwork in the cold has always its peculiarities. We have to fiddle with many tiny little cables that connect into instruments. Some of these often break. Patience and resistance to frustration is something you quickly learn when you work with instruments and delicate cables in the cold. As always, it is a privilege to work up here in the magnificent, bright, Arctic spring with such a nice group of people.
Delicate fiber optic cables connect the radar antenna to the recording console
Team standing ON the Arctic Ocean (sea ice extends out ~4 miles from shore". From left to right: Baptiste Dafflon, Craig Ulrich, Susan Hubbard, John Peterson and me (Alessio Gusmeroli)

Wednesday, May 9, 2012

Finishing Touches...

Today (Tuesday) started slower than most as I stayed behind, while others went to the field, to drop Cathy off at the airport. A morning flight leaves Barrow at 11:00am so I was able to say my goodbyes to Cathy and still be headed to the field by 10:30am. We will meet again sometime in June as Anna and Cathy return to Barrow during peak spring snow melt to assess patterns of surface water flow. The web cam that Bob Busey (UAF) installed last month at our field site will help determine this period of maximum snow melt.

Since I missed a couple of hours in the field already, I took a few extra minutes to drive through Barrow and the old Naval Arctic Research Laboratory (NARL) facilities and take pictures of buildings that our vegetation dynamics team would need to locate when they visit in June. Rich Norby (ORNL), Alistair Rogers (BNL), and others will begin to conduct studies to understand how nitrogen is allocated to structural and functional pools in Arctic plant species and how those patterns of nitrogen allocation govern rates of photosynthetic uptake of carbon dioxide. Chongang Xu (LANL) has developed an optimized nitrogen allocation model that takes into account variation in nitrogen distribution given changes in light, temperature, and elevated CO2 concentration. Chongang is in the process of validating this model now and, once complete, we will further test against data collected in Barrow. Results from these studies will improve our description of plant functional types (PFT) in ecosystem models and then ultimately in climate models like the Community Land Model.

By the time I got back out to the field site, Anna and Sasha had already completed installing two additional sampling wells. One more and they would call it a day, and we would begin moving supplies either back to storage or to Northern Air Cargo for shipment back to Fairbanks.

We leave Barrow later tonight after what was a good and productive week. Susan and her team will stay a few more days to continue geophysical characterization of our field plots. Hopefully she or others from that group will post updates to the NGEE Arctic blog or pictures from their measurement campaign. We have all enjoyed our stay in Barrow and want to thank UMIAQ for providing logistical support. A special thanks to Lance, Glenn, Tony, Brower, and Michael for helping us out and making sure we had everything we needed to complete our science tasks.

We will post again next month, when we return to Barrow with our vegetation dynamics team. Until then, be safe and stay warm...

Tuesday, May 8, 2012

Wrapping Up...

My day was pretty straightforward in terms of science. One more day of research and I would be heading back to a warmer climate. I had plenty of miscellaneous activities, however, to keep me busy for today.

Although I had laid out more than 800 meters of trail mat in the last few days, the teams that would come to Barrow later this summer might need more than what I had delivered. Therefore, while the hydrology and subsurface science teams continued to conduct their research, I managed to gather up an additional 100 meters of trail mat and put it in the back of our pickup truck. Transport out to the BEO was easy enough, as was moving mat from the turnout on Cake Eater road to the control shed on the BEO. I organized a stack of mat behind the shed. It should be available for others on our team to use this summer. The vegetation dynamics group would be the most likely to use additional mat, as they would want to access specific areas for their research especially as they developed new process representations of plant functional types and their incorporation in advanced climate models.

Larry wrote a blog yesterday highlighting the work of our hydrology team. Anna, Cathy, and Sasha have been doing a great job. Just to echo the comments of Larry, this team has done a superb job of drilling water wells, installation of sampling tubes, and then having a network for those in place across polygonal ground so we could begin to characterize gradients in water depth and flow paths during spring snow melt in another month.

One of the side benefits of installing these water sampling wells was the opportunity to acquire soil samples, especially when using the SIPRE coring device. These were often intact cores that allowed a close analysis of soil texture and ice content. Cores extracted from polygon margins often showed evidence of ice-rich regions presumably ice wedges that underlaid low-centered polygons. Although it was often difficult to withdraw intact cores using this approach, we did on occasion obtain permafrost samples that were rich in ice content which varied across the tundra.

Finally, having now spent just two days with my colleagues from LBNL and UAF, it is clear that they are a highly interactive and collaborative group. I sensed this last fall when I joined them for field sampling and I got the same feeling this year. This team talks about data, results, and interpretation of data every chance they get. This is what makes them such a fun group; the NGEE Arctic project is highly integrated and personalities are what makes this a great collaborative activity.

Trips like this one to Barrow reminds me why I got into science in the first place; to ask interesting question about how complex systems function and how that complexity drives ecosystem-scale dynamics. We are eager to share these field experiences with modelers on our team. It is at this stage that things promise to get interesting and where the rewards will be greatest.

White and Bright in Barrow

We’ve competed two days of geophysical acquisition at the same location where we worked last September.  The conditions are quite different – everything is white, white, white; with the snow cover there is little evidence of polygonal ground; and  daytime temperatures  are quite cold (~20F with wind chill). With 24  hours of sunlight, the midnight light is brighter than it gets on sunny days in Berkeley!

We’ve focused to date on EM and radar using different systems, frequencies and acquisition modes – the figures below show 100MHz Sensors and Software radar being acquired by pulling it manually and with a snowmobile. The snowmobiles have been great for pulling around equipment and people (and lets admit it, the snowmobiles have been downright fun). We are starting to recognize geophysical signatures of ice wedges permafrost variability but have lots more to learn.

It has been great to be here with Stan, Cathy, Alex and Anna, who are working on the neighboring plots installing hydrological wells. Everyone is working hard and in good spirits.

Monday, May 7, 2012

Preparing for Spring Snowmelt (by Larry Hinzman)

I was able to join the hydrology team of the first day of well installation.  As most experienced researchers know, persistence and exertion will eventually prevail over adversity, and research in the Arctic sees all that and more.  We continue to be blessed with pretty good weather, but the day was overcast, giving flat light and making it difficult to distinguish variations in the snow.  Days like that can give the feeling of walking around inside a white balloon as one cannot separate the sky from the ground. It had snowed Tuesday, Wednesday and Thursday, but the 16 mph winds were not high enough to lift the new snow more than a few inches off the ground.  This is often called siltation snow, and while not pleasant, it is not unusual nor hazardous.  The risk of white-out conditions does remain following new snow if winds increase to levels of about 35 mph or greater.   Our pre-work safety plan included a discussion on watching the horizon and power poles in the distance.  If visual contact with the powerline becomes tenuous, it is time to pack up and call it a day.  

Spring is coming to Barrow and the snow was also warming.  It was a bit softer and stickier as compared to our April trip, but snowmelt is only a few weeks away.   Snowmelt causes a huge switch in the surface energy balance, it is the dominant hydrologic event, and a tremendous change in all biological activities.  We need to make certain our pre-snowmelt measurements are completed to accurately document the changes that occur between May and June.

Installation of soil water wells was a slow process as drilling into cold frozen ground is difficult.  We were fortunate to have the assistance of Alexander Kholodov of the UAF Geophysical Institute Permafrost Lab with their array of drilling equipment.  Alex used a very large hand-held drill called a Hole Hawg driving specially designed permafrost augers to bore the 1 m holes, which will permanently anchor the wells and reduce frost jacking.  Anna Liljedahl designed the casing with obstructions at the bottom to hopefully maintain a secure foundation in the permafrost. Pipes and stakes placed into freezing ground tend to jack upward over the years as the active layer freezes hard near the surface in the Autumn and then expands upward.  We need to measure the water levels in the wells with millimeter accuracy to allow measurement of groundwater gradients.   This is particularly difficult in areas with such low gradients.  On our previous trip to the BEO, we installed eight benchmarks drilled and driven 9 feet into the permafrost, to which we also added jacking prevention.  Each spring, we will conduct an elevation survey of all benchmarks and wells to ensure correct elevation measurements of the water levels.

Alexander Kholodov of UAF drills 1 m holes into the permafrost
for installation of soil water wells.
Anna Liljedahl and Stan Wullschleger discuss the experimental design
of soil water measurements.

Cathy Wilson records field observations on well placement.
Anna has installed capacitance probes in each well.  This is a new sensor for us, but appears promising for continuously measuring water levels while also being immune to freezing.  This is quite different from the pressure transducers hydrologists have used for the past several decades.

Anna Liljedahl will use a newly improved capacitance probe for continuous measurement of water levels.

Craig Ulrich of LBNL was again a key field party member.  Craig used a differential gps to precisely position each well.  As one can imagine, with continuous snowcover, it would be impossible to know where polygon ridges and troughs are without such equipment.

The NGEE program is fortunate to have the dedicated leadership of our Program Director Stan Wullschleger.  Stan has been central to development of the research plan, and now he is integral to project implementation.  He is the liaison among all researchers, our logistical providers, the general public and our program managers, and has preformed admirably in all cases.  And, he is a hearty field researcher.  Installation of trail mat is essential to protection of the tundra from the impact of dozens of researchers.   Stan has again taken the lead in coordinating and laying out the trail mat.  We will have kilometers of trail mat and installation must occur while snowmachines can still be used to distribute the pallets of mat sections.  But, laying out these trails is still hard work requiring long days of backbending labor.   Speaking on behalf of all those who will use these trails, we appreciate Stan's leadership and his willingness to share his muscles as well as his intellect

Geophysical Survey Gets Going

We picked up Susan and her team at the airport last night and then celebrated their arrival with dinner at Arctic Pizza. It was then back to Hut 163 to organize and get ready for another day of field research.

The following morning, despite cold temperatures, we were eager to get to the field. However, before we could do that Susan, John, Baptiste, and Alessio had to check in with UMIAQ staff, obtain their BEO land use permits and receive training for operation of snow machines. We stopped just long enough for a group picture. Craig and John then headed across the BEO on snow machines while the rest of us drove to the turnout on Cake Eater road. Craig had a sled full of trail mat which would once again be my task for the day.

The LBNL subsurface science team was in Barrow last September for a geophysical survey of the site just before freeze-up in the fall. They were able to get some great data on active layer thickness and characterize subsurface features using ground penetrating radar (GPR), electrical conductivity,  and other geophysical techniques. That information was used to develop a plan for additional measurements using other approaches. The plan was to conduct measurements along the original 450 meter transect (that we established last fall) and then extend those measurements to the four field plots that encompassed low-, high-, and transitional ice-wedge polygons. Information from a range of instruments would be correlated with other ground-truth data and then spatial maps of subsurface features and properties would be used to initialize and parameterize several fine- to intermediate-scale landscape models. Ultimately, insights gained at these scales would inform climate models.

Much of the day was spent testing instruments and equipment. The team functioned well together with lots of energy, compliments of Alessio and Baptiste. Both Alessio and Baptiste are post-docs, one at LBNL and the other at UAF. Each has a unique set of scientific and technical skills, and both have very outgoing personalities which makes working with them a lot of fun. Last September, Baptiste must have walked 10 miles a day collecting subsurface data using an electromagnetic approach. I sense that this trip will be no exception.

Tonight will be spent downloading data and comparing the various signals coming from one instrument or another. We will also discuss a manuscript that Susan is leading based on data collected last fall. Should be fun...

BEO Wall of Fame

Walt Oechel, a professor at San Diego State University, has been a leading figure in Arctic science for many years. In the mid-2000's, he secured funding for what became known as the Biocomplexity Experiment. It involved manipulating water levels on three areas of an old drained lake basin on the BEO. Many people have been associated with that study over the years and still more have visited the "control shed" that once served as a command center for Walt's one of a kind experiment.

One wall of the control shed contains the signatures of people who have worked on, or otherwise visited, the Biocomplexity Experiment. Here are a few pictures of that wall of fame...

Everyone Knows Their Job

Having now been in Barrow for a few days, each member of our team has fallen into a routine of field measurements or has at least narrowed the scope of activities that need to be completed. There are individuals and/or small teams scattered across the tundra doing everything from hydrology to site establishment. Our corner of the Barrow Environmental Observatory (BEO) is a hotbed of research right now and that looks to continue for the next 10 days as we will soon be joined by Susan Hubbard (LBNL) and her team. That will bring our number to 9 people.

But I'm getting ahead of myself...

Today, while Cathy and Sasha were busy installing water sampling wells (that will be the focus of an upcoming post), Anna has taken the opportunity to evaluate an automated snow depth probe that she brought with her from the University of Alaska Fairbanks. The probe itself is a long slender rod that is equipped with a sliding base plate. As the rod is inserted to the base of the snow layer, a sensor detects the depth with centimeter resolution. The sensor is connected to a data logger so that data points can be quickly saved. There is an additional button that, when pushed, logs the location of each measurement via a high-resolution GPS unit that Anna wears on her back. This series of steps is repeated across a 75 x 75 m core plot within our measurement areas. She has logged well over 4000 points in the last 2 days. Spatial maps of snow depth complemented by LiDAR imagery and topography will be pretty amazing.

My job of laying trail mat has been a daily activity since we arrived in Barrow. We want to protect the fragile tundra from foot traffic and trail mat is one way to do that. You can imagine that walking directly on the tundra would damage vegetation and soils so trail mat will confine our steps to specific protected areas.

Several days ago I posted a few pictures of the transport of trail mat to our field site using a sled towed behind a snow machine. This has worked surprisingly well. We can haul upwards to 225 individual mats on a single sled. We off-load those at one or more locations and then use a smaller sled to move mats to specific areas. My technique for placing trail mat in long straight paths is better than it was a few days ago.

I should be done installing trail mat tomorrow and can then turn my attention to helping others. The geophysical survey group from LBNL and UAF arrive tonight. It will be good to see them in action. We had a similar field geophysical campaign last fall and have had several good publications drafted from those studies already. Anna and Sasha will continue to install water wells and I will highlight pictures of those activities later in the week.

Friday, May 4, 2012

First NGEE Geophysical Winter Campaign

The NGEE geophysical team is on the way to Barrow for its first ‘winter campaign’.  Last September, the team  conducted its first ‘active layer characterization campaign’, which  included acquisition of a variety of geophysical and point measurements along a permafrost gradient where lidar data were also available. Analysis of the datasets, individually and in combination, revealed the utility of the methods for characterizing critical active layer and land-surface properties and their relationships; results were presented at the EGU meeting in Vienna two weeks ago.
Team (standing in the Arctic Ocean) from left to right:
Stan Wullschleger (ORNL), Baptiste Dafflon (LBNL),
Craig Ulrich (LBNL), Susan Hubbard (LBNL),
John Peterson (LBNL)and Alessio Gusmeroli (UAF), Sept 2011. For this May
campaign, Jonathan Ajo-Franklin (LBNL) will also join us.

First Geophysical Field Campaign
The objectives of this campaign are threefold: (1) to characterize the ground ice beneath the active layer at the same location as the previous campaign; (2) to test a new seismic methodology for quantifying ground ice characteristics; and (3) to collect a variety of geophysical data in a nearby area to provide a foundation for other measurements that will be made by other NGEE groups during the upcoming growing season. 

We are excited to again be working in Barrow together again, worried about the instrumentation performance in this cold weather, and curious to explore the geophysical responses to the frozen ground. Stay tuned!

Plenty of daylight

Jet lag is just one cause of lost sleep when traveling across 4 time zones in a 16 hour period. So too is going to bed at midnight, knowing that the sun is still on the horizon and that daylength in the Arctic is about 21 hours. Either way, I woke up early, made myself a cup of coffee, and ventured out to begin moving trail mat to the tundra. It had snowed last night and the forecast was for light blowing snow and clouds. Temperatures hovered at zero.

As expected, and as arranged with UMIAQ, 8 or 9 pallets of GeoBlock were wrapped, stacked, and ready for transport. These plastic mats are right at a meter in length and arranged 96 per pallet. The mat itself is well deigned and can be placed end-to-end and connected with overlapping tabs and secured with screws.

Tony, from UMIAQ, made the first run of the day after he positioned trail mat on a wooden sled to be towed behind a snow machine. Having snowed last night, the weight of the trail mat tended to weigh the sled down, causing the runners to dig into the snow. It made for a slow pull out to the field site. However, once delivered, Larry and I were able to lay 100 meters of trail mat in about an hour. We both laid out walkways that had a slight curve despite a desire to lay trail mat in a straight line. Oh well, we will correct alignment later.

We also took time after lunch to look into lab space. UMIAQ has lab space available in the Barrow Arctic Science Center (BASC). We have several tasks this coming summer that require access to quality lab space; something that is at a premium in Barrow. As it turns out, a couple of labs are potentially available and we took an hour to look at a few spaces. These are really nice labs with all the standard features of a modern lab complete with eye wash stations, fire extinguishers, and safety showers. It is too early to tell, but we hope that similar space can be secured for our NGEE Arctic project.

Finally, as a complement to available lab space, we have been asking scientists who work in Barrow about common facilities like cold rooms, -80C freezers, and ovens. Ken Hinkel, from the University of Cincinnati, gave us a heads-up on a large upright oven that he has used for drying soils. I located the oven in one of the UMIAQ buildings. It looked well maintained and clean. I turned it on and adjusted the temperature to 70C. The oven worked great. While we may need to purchase a small oven for our use in a lab, this oven is going to be perfect for drying larger soil and plant samples later this summer. We thank Ken for sharing his resources.

We also made progress on installation of water sampling wells. Anna, Cathy, Alex, and Craig evaluated a few options this afternoon and are huddled around the table now deciding on a path forward.   Should be ready to go in the morning; early.

Thursday, May 3, 2012

Planning Ahead, Getting the Job Done

Everyone who travels to Barrow as a participant in the NGEE Arctic project is expected to have done two things before their trip. The first is to have outlined a scope of work that can be traced to tasks in our proposal. It is critical that we know what needs to be done prior to our arrival in Barrow. Barrow is not the place to begin thinking about the science question you want to address. The second is to have a thoughtful and thorough work plan that identifies what must be accomplished and who needs to tackle specific tasks in order to deliver on expectations. Susan Hubbard and her LBNL geophysical science team set a good example for how this should be done last September, as did David Graham and his ORNL permafrost sampling team during a trip to Barrow just last month.

It is now my turn to put a work plan into action. It is my goal to spend the coming week laying out GeoBlock trail mat across our field plots on the Barrow Environmental Observatory (BEO). Our team had previously developed GIS overlays of the BEO and located our field plots across a series of low-, high-, and transitional polygons. Because the tundra is so sensitive to foot traffic, a network of boardwalks and trail mat are a good way (and probably the only way) to limit damage to tundra vegetation and to the surrounding landscape. This is an important component of our site establishment plans and these mats need to be installed prior to the arrival of our vegetation team in June.

The resolution of the aerial and remote-sensing images we are using in support of our site establishment activities is amazing. We have made especially good use of the high-resolution LiDAR images that were provided by Craig Tweedie from the University of Texas at El Paso. Craig and his students have conducted research for many years in the Barrow area. With help from Garrett Altmann at LANL, we have optimized the placement of these protective walkways, leveraging to the best of our abilities wooden boardwalks in the vicinity of our field plots. Although it will not be a trivial undertaking, we should be able to access each of our plots with the addition of 700 meters of new trail mat. Note the spatial detail provided by LiDAR images of low- and high-centered ice-wedge polygons in the area of our field plots. This is a great illustration of patterned ground in the Arctic.

We landed in Barrow at 7:35pm Alaska time, just a little more than 16 hours since I departed Knoxville this morning. Larry and Cathy picked us up at the airport, we gathered our luggage, and then headed off to our lodging for the week. Over the last 6 months, we have grown accustomed to Hut 163, a bunkhouse-style housing unit that sleeps 8 people. It has a small kitchen, a 250 gallon water tank that gets filled upon request, and a heating system that takes the chill off the 10F temperatures outside. Our NGEE Arctic home away from home...

And last, but not least, Craig and I verified that pallets of trail mat were ready to be moved out to our field plots tomorrow. I love it when a plan comes together.