Tuesday, November 11, 2014
The NGEE Arctic team has enjoyed a great 10-day trip to Barrow. We accomplished everything that we had planned and did so under constraints of short days and low temperatures; but that’s the Arctic. Our team has plenty of activities for this winter, including the quickly approaching Fourth Annual NGEE Arctic All-Hands meeting followed by strong participation in the American Geophysical Union (AGU) meeting. Both of these will be in San Francisco. I look forward to seeing many members from our team during those two back-to-back meetings.
For now, however, we close out another field season in Alaska. Those of you familiar with our blog know that I often save a particularly appealing or amusing picture as our “Pic of the trip”. This week there were several that I personally enjoyed including the sun dipping below the horizon as I landed in Anchorage and the sunrise one morning on the Barrow Environmental Observatory. My favorite, hands down, was one taken of Ori as she enjoyed Häagen-Dazs ice cream one afternoon on the tundra. This might not seem too odd except it was -17F at the time. Ori commented that unlike the summer, she has no trouble keeping her ice cream frozen during winter trips to Barrow. I do recall seeing an ice cream bar often stuck into a nearby snow drift while she took flux measurements all week! Thanks Ori…
Researchers working on the NGEE Arctic project are physically on-site between later May and Early November. So, data collection and equipment maintenance proceeds without too many delays or interruptions. Once the days get short and the temperatures plummet, data continues to be collected but it requires considerable automation, especially of the sophisticated electronics we have deployed at the site. Now is a good time for Bryan and Keith to upgrade some of our sensors and instruments, and begin to prepare for the long, dark winter ahead. Today was spent installing a couple of new electronic control panels that house multiple marine cycle batteries and an uninterruptable power supply. This set-up will be sufficient to run our electrical resistivity tomography (ERT) transect, our networks of soil temperature and moisture sensors, and two cameras. One is positioned along the ERT transect and the other is installed as part of the PhenoCam, an ecosystem phenology web camera network run by Andrew Richardson (Harvard) and others. Although the cameras will not capture useful images for 4 to5 months, they will be up and running via remote operation during critical periods of transition including snowmelt and vegetation regrowth. Bryan and Keith worked hard this trip to get these upgrades in place, so my thanks to these talented and patient members of the team.
The NGEE Arctic team has been challenged this week to complete all our tasks between sunrise and sunset. The short days, less than 5 hours, mean that we are spending another day collecting permafrost samples and measuring CO2 and CH4 fluxes. We headed out to our field sites today before sunrise thanks to good organization yesterday and UMIAQ having the snow machines checked out and full of gasoline. The trip only took 30 minutes and just as the sun rose above the horizon, John had located our first sampling location for the day. He also used the dGPS to locate a few measurement sites for Ori. One of our goals in measuring the flux of greenhouse gases from polygons on the North Slope of Alaska is to better understand the role of spatial variability in CO2 and CH4 flux rates related to hydrology, geochemistry, and vegetation. These are complex landscapes with a diversity of low- and high-center polygons that dot this area of Arctic coastal plain. So, our measurement sites, which easily total more than 100, are distributed across center, rims, and troughs. These features are now frozen and most are now covered with snow, but throughout much of the year these microtopographic features present a wide range of soil and environmental conditions that contribute to observed rates of greenhouse gas fluxes. Our team needs this information to better understand what controls fluxes and how that knowledge can then be used to improve climate predictions. We are collecting other data from the permafrost cores under controlled laboratory conditions to evaluate observations in the field. This multi-scale aspect is unique to our project and provides an opportunity to draw connections between laboratory and field estimates of flux. Ori and other colleagues on the project have literally collected thousands of flux estimates in the field over the season. Once back in the office these data will need to be analyzed and results interpreted. Once analyzed the data nd resulting insights can be shared with the modelers on the project for incorporation into their simulations.
Friday, November 7, 2014
This morning we met at our storage building and set about organizing materials and supplies that we either brought in from the field yesterday or that had accumulated throughout the summer. Bryan and Keith shouldered most of the burden, but made good use of the time to also make sure that they had everything they needed to update the electronics and controls for the tram. We brought back the unit that powered and controlled the automated tram earlier in the week and now will spend a few days improving the operation and reliability of the system for deployment later in the week. It is great that UMIAQ, our logistics provider, has a lot of floor space where we can spread out and sort through all that we have brought to Barrow.
While Bryan and Keith were busy in the storage area, John, Ori, Naama and I headed out for a day of field research. Once again we relied on snow machines and sleds to transport all our instruments and equipment. Once at our field site we were treated to an amazing sunrise at 10:45am. Compared to the cloudy weather that we have had to date, today was sunny and windy. We quickly got to work. John and I started by collecting permafrost cores while Ori and Naama continued to measure CO2 and CH4 flux from several transects. John and I needed to collect nine cores associated with plots that Lydia (LBNL) is measuring as part of her PhD dissertation research. We were successful in collecting six cores before sunset at 3:45pm. It was interesting to see the upper 10 to 15 cm of active layer soil had frozen already, but that underlying soils down to 35 to 40 cm were still unfrozen. This presented a challenge of getting the cores out of the barrel of the SIPRE, as the soils immediately began to freeze in the SIPRE once brought up into the air. This proved to be an unexpected complication and slowed us down. John and I will need to get the remaining three cores tomorrow. These cores will be shipped back to UC Berkeley where Lydia will be analyzing them for SOM, carbon content, and 14C dating.
While John and I collected cores, Naama and Ori gathered data on CO2 and CH4 fluxes. They moved methodically across the tundra, letting the equipment equilibrate, and then making flux measurements over a 4 to 6 minute period. These data will be added to other data collected throughout the season. It should be a great dataset and one that will help us as we seek to improve models, especially climate models for the Arctic.
Thursday, November 6, 2014
Last May the NGEE Arctic team designed, built, and assembled a 65-meter long tram on the Barrow Environmental Observatory (BEO). The tram consisted of supports, rails, and a motorized cart that carried energy and radiation sensors back and forth across the tundra every 3 hours. It has been operating all summer with few problems. The reliability of the tram is a testament to those who designed the system – Keith Lewin, Bryan Curtis, and Paul Cook. Nice job guys!
Today we set about taking down the rails, supports, and cart for the winter. Keith and Bryan are going to redesign a few things over the winter and add a sensor or two. This will require strengthening the overall infrastructure and reprogramming some of the software. Although this could be done in the field, it makes sense to remove everything now (as per our North Slope Borough (NSB) permit and other safety considerations) and reassemble the new and improved system in the spring before snowmelt.
So, first thing this morning we set about strategically removing clamps that held the rails, and the few nuts and bolts that held the vertical supports. This literally took less than an hour. It was a pretty impressive design with considerable thought given to how the tram could be quickly assembled, and dissembled, in harsh weather. The hardest part was transporting the 16 foot rails and upright supports back to our storage facilities in Barrow. Sleds made this bearable and once everything was strapped in place, John and Bryan could run them back to town in 30 minutes. Two trips were required to get everything safely transported and stored until next spring.
Everyone was glad to have this completed before the end of the day. The winds kicked up to 20 miles per hour this afternoon and the wind chills dropped below -10F. Wind speeds are forecast to increase overnight and into tomorrow so this was a task we were glad to check off our list.
Wednesday, November 5, 2014
The NGEE Arctic team is committed to collecting quality datasets that can, in turn, provide knowledge to inform climate models. We are doing this for several disciplines including hydrology, biogeochemistry, and vegetation dynamics. One area where we are especially focused is on the measurement CO2 and CH4 flux from polygonal landscapes on the North Slope of Alaska. These two greenhouse gases, both products of thawing and degrading permafrost, are important inputs to the atmosphere that determine the rate and magnitude of future warming of the planet.
Today our team left the Building 142 staging area a few miles east of Barrow and traveled to our field site using snow machines. John used a Topcon dGPS to identify locations for our measurements. He will eventually locate 65 to 70 sites buried beneath 10 to 50 cm of snow, but today John focused on plots along the 65-meter long tram. PVC collars had been installed along the tram earlier in the year and project scientists have been measuring CO2 and CH4 flux routinely throughout the year. Once identified, the collars were gently cleaned and an LGR system was used to measure fluxes per unit ground area over a few minute period. Ori and Naama were able to take all the measurements within a few hours of admittedly limited daylight. It was surprising that despite snow, frozen ground, and ice we were still able to measure positive, albeit low, fluxes for both CO2 and CH4. It will take a few weeks to analyze the data but these final measurements should complete what has been a rewarding and successful 2014 field campaign.
John continues to locate other sites where we will conduct similar measurements tomorrow. We will also be collecting samples of air from stainless steel “gas wells” that had been previously inserted into the active layer.
Tuesday, November 4, 2014
John and I woke up early (or at least it was still dark), had breakfast, and then organized everything that had been in storage. Several boxes of equipment had not yet arrived, so we also stopped by Northern Air Cargo (NAC) in hopes of locating them. We quickly found one, but will have to wait until tomorrow to retrieve the other. Bryan, Ori, and Keith arrived at the airport about 10:30am and we soon had everyone checked in, organized, equipped, and dressed for the field, thanks to our logistical provider UMIAQ.
Snow machines made getting to our research site quick and easy. Each year we receive a safety briefing on the proper use and operation of snow machines and today was no exception. However, that took less than 30 minutes and we were on our way just after lunch. Bryan and Keith examined the tram and all it sensors. We will let it collect another day of data before beginning the disassembly. John got the dGPS up and running and guided Ori and I to each of our locations where we will measure CO2 and CH4 flux using static chambers beginning tomorrow. Most of these were under snow so it took a few hours of careful excavation to get them ready to measure. Ori and Naama (arriving tonight) should be able to start measurements early tomorrow morning. This set of measurements will be the end of what has been a season-long effort to get estimates of CO2 and CH4 flux before snowmelt, throughout the summer, and now into the winter. This should be a great dataset of model development, validation, and for comparison against larger-scale estimates of carbon cycle processes with the eddy covariance system. More about that tomorrow…