Globally, soil organic matter (SOM) contains more than three times as much carbon as either the atmosphere or terrestrial vegetation. Yet it remains largely unknown why some SOM persists for millennia whereas other SOM decomposes readily—and this limits our ability to predict how soils will respond to climate change. Recent analytical and experimental advances have… More

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Measurements of net ecosystem CO2 exchange (NEE) and energy balance were made using chamber-, tower-, and aircraft-based measurement techniques in Alaskan arctic tundra ecosystems during the 1994–1995 growing seasons (June-August). One of our objectives was to quantify the interrelationships between the NEE and the energy balance measurements made from different sampling techniques. Qualitative and quantitative… More

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The spatial and temporal patterns in CO2 flux for the Kuparuk River Basin, a 9200-km2 watershed located in NE Alaska were estimated using the Regional Arctic CO2 Exchange Simulator (RACES) for the 1994–1995 growing seasons. RACES uses non-linear models and a Geographical Information System database (GIS) consisting of the normalized difference vegetation index (NDVI) and… More

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This paper summarizes and analyses available data on the surface energy balance of Arctic tundra and boreal forest. The complex interactions between ecosystems and their surface energy balance are also examined, including climatically induced shifts in ecosystem type that might amplify or reduce the effects of potential climatic change. High latitudes are characterized by large… More

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Biome differences in surface energy balance strongly affect climate. However, arctic vegetation is considered sufficiently uniform that only a single arctic land surface type is generally used in climate models. Field measurements in northern Alaska show large differences among arctic ecosystem types in summer energy absorption and partitioning. Simulations with the Arctic Regional Climate System… More

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Recent evidence indicates that significant amounts of C may be lost as CO2 to the atmosphere from tundra ecosystems during the fall, winter and spring months. Because high latitude ecosystems are particularly vulnerable to climate change, and contain large soil C stocks, the annual C budget is of particular interest. Significant amounts of CO2 loss… More

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Assessments of carbon (C) fluxes in the Arctic require detailed data on both how and why these fluxes vary across the landscape. Such assessments are complicated because tundra vegetation has diverse structure and function at both local and regional scales. To investigate this diversity, the Arctic Flux Study has used the eddy covariance technique to… More

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Estimates of annual carbon loss from arctic tundra ecosystems are based nearly entirely on measurements taken during the growing season in part because of methodological limitations but also reflecting the assumption that respiration during winter is near zero. Measurements of CO2 flux during winter, however, indicate significant amounts of carbon loss from tundra ecosystems throughout… More

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