Arctic Field Projects

Project Title: Collaborative research: Nonlinearities in the Arctic climate system during the Holocene (Award# 0909332)

PI: Kaufman, Darrell S (
Phone: (928) 523.7192 
Institute/Department: Northern Arizona University, School of Earth Sciences and Environmental Sustainability 
IPY Project? NO
Funding Agency: US\Federal\NSF\GEO\OPP\ARC\ARCSS
Program Manager: Dr. Neil Swanberg (
Discipline(s): | Geological Sciences\Climate Change | Geological Sciences\Paleolimnology |

Project Web Site(s):

Science Summary:
This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). A major goal of the Arctic System Science (ARCSS) Program is to understand the variability of the Arctic system and the feedbacks that lead to pronounced system changes, such as those that are currently taking place. Rapid changes in the Arctic climate system that occurred in the relatively recent past can be compared with the output of climate models to improve the understanding of the processes responsible for nonlinear system change. In particular, this study focuses on the transition between the Holocene thermal maximum (HTM) and the onset of Neoglaciation, and on the step-like changes that occurred subsequently during the late Holocene. The millennial-scale cooling trend that followed the HTM coincides with the decrease in Northern Hemisphere summer insolation driven by slow changes in Earth’s orbit. Despite the nearly linear forcing, the transition from the HTM to the Little Ice Age (1500-1900 AD) was neither gradual nor uniform. To understand how feedbacks and perturbations result in rapid changes, a geographically distributed network of proxy climate records is proposed to study the spatial and temporal patterns of change, and to quantify the magnitude of change during these transitions. Intellectual merit. The 12 PIs of this collaborative project will use lacustrine sediments to produce 13 new high-resolution proxy climate records of the past 8000 years. The study sites form two focus regions (eastern Beringia and the NW Atlantic) that generally coincide with the nodes of the surface temperature expression of the Arctic Oscillation (AO). This project will nearly double the number of high-resolution lacustrine records that extend through the last two millennia, and will generate some of the first highresolution records that capture the HTM. During the HTM, summer sea-ice cover over the Arctic Ocean was likely the smallest of the present interglacial period; certainly it was less extensive than at any time in the past 100 years, and therefore affords an opportunity to investigate a period of warmth similar to what is projected during the coming century. This study focuses on lakes because lakes are the most widely distributed sources of proxy climate records that consistently extend through the post-glacial interval. Because climate change is amplified in the Arctic, the climate signal preserved in Arctic lake sediments should be stronger than elsewhere. The proxy records generated in this project will use conventional and newly emerging techniques to document the spatio-temporal patterns of abrupt environmental changes, and to derive quantitative estimates of past summer temperature and hydroclimate variables. Most lakes have been cored previously and show potential for generating high-quality proxy records. Five of the lakes contain laminated sediment with annually resolved records; others have high sedimentation rates (>0.5 mm yr-1) for sub-decadal resolution across the climate transitions. Confidence in the paleoclimate reconstructions will be bolstered by a multi-proxy approach, and by replicate lake records in each of the focus regions that will be used to distinguish basin-scale thresholds from regional-scale climate shifts. This project builds on on-going climate-modeling experiments that use NCAR’s Climate System Model (CCSM3) to study the sensitivities of the Arctic system to volcanism and solar variability. A new data-model comparison proposed for this study will test whether the most prominent changes in the Arctic system during the past 8 ka, as reconstructed from the proxy records, can be explained by a plausible combination of system-component conditions coincident with prolonged volcanism. The experiments, conducted with NCAR collaborators, will focus on the elements of the Arctic system (e.g., AO and extent of sea ice) that participate in abrupt transitions, and that might elicit nonlinear changes in the future. Broader impact. This project will contribute to understanding climatic variability, a key challenge facing society. Specifically, it will provide insights into the feedback processes that cause the climate system in the Arctic to change faster than any other region on Earth. The spatial network of paleoclimate reconstructions will serve as key benchmarks for validating climate models and for improving their ability to accurately simulate nonlinear change, including changes in sea-ice cover. This project brings together experts from the paleo- and the climate-modeling communities to resolve the apparent underestimate of the sensitivity of sea ice to change within climate models. Improving models for future climate projections will contribute to the “Climate Variability and Change” major program element of the US Climate Change Science Program (CCSP). The project will also contribute to several ARCSS initiatives including, “Changing Seasonality in the Arctic System” (CSAS), among others, and to the new NSF initiative, “Paleo Perspective on Climate Change” (P2C2). It will bring together international collaborators from Europe and Canada who are involved in several new and proposed parallel initiatives to expand the spatial network of high-resolution proxy-climate records across the Arctic. The project will train nine graduate students and at least as many undergraduates in global-change and system-science research, and will support two postdocs and several junior faculty members.

Logistics Summary:
This is a 10-institute collaborative led by N. Arizona U (Kaufman 0909332), and including U at Buffalo (Briner 0909334), UAF (Wooller 0909523), Lehigh (Yu 0909362), Alaska Pacific (Loso 0909322), U Pittsburgh (Abbott 0908200), U Illinois (Hu 0907986), CU Boulder (Miller/Axford/Lehman 0909347), U Mass (Bradley 0909354), Idaho State (Finney 0909310). The twelve PIs will use lacustrine sediments to produce fourteen new high-resolution climate records of the past 8000 years. The pattern of climate changes recorded in the proxy records can be studied and compared with the output of climate models to gain an understanding of the non-linear processes involved in system change. Most research groups plan separate field campaigns. Hence, logistics details are found under each individual grant. Kaufman will conduct a two-week coring project in March 2010. The field team of seven will assemble in Anchorage, there meeting an NSF truck and snowmachine provided out of the Fairbanks fleet. The team will drive to Valdez, and ferry to Cordova, where they will base for the coring activities. They will spend about a week coring area lakes before focusing on Summit Lake near Paxson for about a week. The team will travel to the lakes via snowmachine and core from the ice. When the work is complete, the team will drive back to Anchorage and depart Alaska via commercial air. PFS staff will then pick up the truck and drive it back to Fairbanks.

CPS support includes snowmachines/sleds and trailer, safety equipment, satellite phone, ice auger, truck rentals and trapper cabin lodging. All other logistics, including lodging, food, fuel, and other field consumables, will be paid from the grant.
SeasonField SiteDate InDate Out#People
2010Alaska - Cordova03 / 05 / 2010 03 / 20 / 20107
2010Alaska - Tonsina Lake03 / 05 / 2010 03 / 20 / 20107

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