Leaving Nome, with the sea and sea ice in the background.

1. Expedition route. Five weeks, 20 March–26 April 2002, 1050 miles (1700 km), minimum temperature –30 F (–34 C). Figure at right shows the equivalent distance over the conterminous United States.

2. Expedition Purpose/ObjectivesRecent research has suggested that the Arctic may be particularly sensitive to global climate changes. In fact, model simulations suggest that a warming in the Arctic could be many times greater than a warming in middle latitudes. The ultimate objective of this expedition is to understand the possible consequences of arctic climate changes, particularly from the perspective of how warmer temperatures might lead to changes in vegetation growth and the resulting impacts on snow distributions, snow characteristics, snowmelt runoff, soil temperatures, and permafrost and active-layer characteristics.

3. Expedition Purpose/Objectives, continuedA key finding of our previous research has been that in arctic environments the snow and vegetation are tightly coupled, and that arctic climate change studies must take a close look at the relationships between the two in order to understand the consequences of climate change in arctic regions. For example, if the current tussock-tundra vegetation is replaced by shrubs under warmer conditions, this causes more snow to accumulate on the tundra, this insulates the ground from the low winter temperatures, which can grow more shrubs and can thaw the permafrost, which releases carbon stores, which may accelerate the atmospheric warming. As another example, the snow held within the shrubs is very soft and difficult to travel through; this could affect caribou migration patterns, which could impact calving grounds and calving success.

4. Expedition Purpose/Objectives, continuedField measurements were made along a transect from Nome to Barrow, Alaska. This transect consists of a dramatic change in winter snow, vegetation, and climate. Barrow is in a flat, nearly shrub-free region near an ocean that has a continuous winter sea-ice cover and therefore limited cyclonic (storm) activity. At Nome, shrubs and scattered trees are prevalent, the topography is complex, the winter sea-ice cover is not continuous, and cyclonic activity can be intense. This transect can be thought of as approximating climatic conditions that might be experienced at a single point as the arctic climate changes. Thus, by studying the changes in snow and vegetation conditions along the transect from south to north, we can gain insights into what might happen if warmer conditions move north.

5. Expedition Purpose/Objectives, continuedOur field measurement protocols were developed to accomplish three main objectives: 1) understanding the depth distribution and physical snow characteristics of the snow cover at a wide range of spatial scales (meters to hundreds of kilometers), 2) understanding the vegetation distributions and characteristics at the same scales, and 3) understanding the interrelationships between the snow and vegetation characteristics. These measurements will then be used to develop models that will allow us to describe how climate changes might impact snow, vegetation, and climate features and characteristics throughout the Arctic.

6. Expedition Purpose/Objectives, continuedAs part of the research expedition, an 8th-grade science teacher (April Cheuvront) developed an education and outreach program. As part of this program Ms. Cheuvront sent daily science lessons (via satellite phone) to her school classes, and we visited the schools located along our route, teaching the children about snow and climate science. In addition, Ms. Cheuvront assisted with all of the field measurements collected during the expedition.Institution Sponsoring the ExpeditionThis expedition was funded by Dr. Michael Ledbetter, Arctic System Science Program Manager, Office of Polar Programs, United States National Science Foundation as part of Dr. Matthew Sturm's and Dr. Glen Liston's NSF project "Snow Weather and Shrubs: Pathways of Change in the Arctic".Ms. Cheuvront’s contribution was funded by NSF’s Teachers Experiencing Antarctica and the Arctic (TEA) program. Her web site developed as part of this program can be found at http://tea.rice.edu/tea_cheuvrontfrontpage.html.

7. Dr. Matthew Sturm, Expedition Leader (left). Dr. Glen Liston, Co-Science Leader (right) with Matthew.

8. Jon Holmgren, Chief Science Technician (left). Eric Pyne, Chief Logistics and Field Supervisor (right).

9. April Cheuvront, 8th Grade Science Teacher, Table Rock Middle School, North Carolina (left). Ken Tape, Graduate Student, U. of Alaska, Fairbanks (right).

10. A pre-expedition planning meeting in Fairbanks. Talking about where we are going, and whether we have forgotten anything.

11. Buying food for the expedition. Chocolate was a big hit for this group! During the expedition we consumed about 7000 calories per person per day to help compensate for the hard work and low temperatures.

12. Taking our equipment and supplies to the airport in Fairbanks for transport to Nome and the start of our trip.

13. Leaving Nome, with the sea and sea ice in the background.

14. On the traverse we had six snowmobiles, three pulling two sleds each, and three pulling single sleds. Each sled weighed about 350 lbs (160 kg).

15. Our food bins were identified as containing either breakfast, lunch, or dinner. These five bins represent about half of our food. The other five bins were shipped ahead to Ambler and the Ivotuk cabin.

16. This is the SnowSTAR sled. This was designed and built by Jon, specifically for this expedition. It includes a propane heater, solar panels that charge batteries to run our computers and other electronic science equipment, ports in the sides to pass out computer cables, and a table and two seats. It is big enough to hold two people working on computer data entry and data analysis.

17. We had 83 main measurement sites along the traverse. Each site included a 100-meter line where we measured snow depth every 0.5 meters, and made snow-pit and snow-water-equivalent measurements every 25 meters. The snow blocks are left over from digging the snow pits.

18. A typical camp setup. We had two tents, a large one for three people, a small one for two people, and one person slept in the covered sled.

19. It was always important to make sure the supplies on the sleds were lashed down good and tight. We could not afford to lose anything on this trip (especially things like sleeping bags and extra warm clothing).

20. Camp setup. A two-burner propane stove was used for cooking, and we had a small wood stove in the big tent to thaw out cold fingers and toes.

21. Melting snow for water, every morning and evening. This water was then put in thermos’ to keep the water from freezing during the day. Jon taking a water/coffee/tea/cocoa/lunch break.

22. Ken with the GPS MagnaProbe. This was invented by Matthew and Jon, and is used to automatically record the snow depth and the global position of that depth.

23. April running the light-penetration instrument. This measures the intensity of solar radiation below the snow surface, and how it changes with depth. The instrument is run from a computer (and person!) inside the SnowSTAR sled.

24. Matthew in a shallow snow pit. Glen in a deeper one.

25. Matthew measuring snow temperature (left), and snow hardness profiles (right).

26. April collecting snow-water-equivalent samples, and Glen weighing them.

27. Eric measuring deep snow in the forests south of the Brooks Range.

28. This instrument is a penetrometer that measures snowpack hardness.

29. Eric in the SnowSTAR sled, and Matthew and Glen outside, running a penetrometer experiment.

30. Every day we would break camp and move on to the next measurement sites. At the end of the day we would find a sheltered spot out of the wind. This was usually in the bottom of a small valley or on top of a frozen, snow-covered river.

31. Village life. Ambler, and a very small sled dog eating a piece of frozen fish.

32. We stopped in all of the villages along our route, spending a day teaching the children about snow science. Ken (left), Eric (top), April (bottom).

33. Jon (left) demonstrating an alternative use of the MagnaProbe: measuring the heights of young students. Also showing what it is like to write in field books with big mittens.

34. Letting the Atqasuk students try their hand at making snow measurements.

35. The people in the villages use poles to mark their winter trails between the villages.

36. Matthew refueling a snowmobile (Eric in back). We bought fuel in the villages and had deposited a fuel cache at the Ivotuk cabin last summer.

37. A cold morning.

38. Ken picking out a desert from the lunch bin. Glen checking on dinner.

39. Ken running a light attenuation experiment, while Eric sets out on a 100-meter MagnaProbe snow-depth line.

40. Collecting snow-chemistry samples, complete with Tyvek suits, and very cold rubber gloves. Glen (above) and April collected these samples (they were the only ones that could fit in the suits with their parkas and overpants on).

41. A nice winter snow storm.

42. Matthew making snow-density measurements in the snow pit wall.

43. Eric in the heart of the Brooks Range.

44. A cold crossing over the crest of the Brooks Range. Bottom picture, from left to right: Eric, April, Jon, and Ken.

45. Crossing over a high point in the Brooks Range, and over a flat area of Alaska’s North Slope.

46. Forests to the south of the Brooks Range (left), no forests to the north (right).

47. April enjoying her first trip to the Arctic.

48. Keeping our noses from freezing at –30 F (–34 C). Jon (left), April (center), and Eric (right). Large zipper-pulls are nice when wearing big mittens (top right).

49. Dinner (or breakfast) in the big tent (Matthew, left; Eric, right). We had three cots around the outside edge of the tent, and then the small wood stove in the middle. This stove allowed us to eat without mittens/gloves/hats/parkas on.

50. April searching for fossils on the cliffs north of the Brooks Range.