Search Results
1. Introduction Boreal forest and arctic tundra biomes of the northern high latitudes (>40°N) are currently undergoing significant changes coinciding with recent and persistent climatic warming ( Serreze et al. 2000 ; Comiso 2003 ). Terrestrial ecosystem responses to the warming trend include thawing permafrost and deepening soil active layer depths ( Oelke et al. 2004 ), advances in the timing and length of seasonal growing seasons ( Myneni et al. 1997a ; McDonald et al. 2004 ), changes in
1. Introduction Boreal forest and arctic tundra biomes of the northern high latitudes (>40°N) are currently undergoing significant changes coinciding with recent and persistent climatic warming ( Serreze et al. 2000 ; Comiso 2003 ). Terrestrial ecosystem responses to the warming trend include thawing permafrost and deepening soil active layer depths ( Oelke et al. 2004 ), advances in the timing and length of seasonal growing seasons ( Myneni et al. 1997a ; McDonald et al. 2004 ), changes in
region during the last two decades of the twentieth century. The boundaries of the western Arctic in this study completely encompass the drainage basin of the Yukon River, and the region includes most of Alaska and adjacent areas in northwestern Canada. The region includes two long-term ecological research (LTER) sites: one that is focused on tundra ecosystems (Toolik Lake LTER; Hobbie et al. 1994 ) and another that is focused on boreal forest ecosystems (Bonanza Creek LTER; Chapin et al. 2006
region during the last two decades of the twentieth century. The boundaries of the western Arctic in this study completely encompass the drainage basin of the Yukon River, and the region includes most of Alaska and adjacent areas in northwestern Canada. The region includes two long-term ecological research (LTER) sites: one that is focused on tundra ecosystems (Toolik Lake LTER; Hobbie et al. 1994 ) and another that is focused on boreal forest ecosystems (Bonanza Creek LTER; Chapin et al. 2006
1. Introduction Changes are occurring to high-latitude environments with further alteration likely under several global change scenarios. Responses in the arctic environment may include alterations to the landscape and in water fluxes and stores. While conceptual water balance models have proved useful in assessing contemporary hydrological conditions and in modeling future states, general circulation models have not proved accurate enough to close water budgets in hydrological applications
1. Introduction Changes are occurring to high-latitude environments with further alteration likely under several global change scenarios. Responses in the arctic environment may include alterations to the landscape and in water fluxes and stores. While conceptual water balance models have proved useful in assessing contemporary hydrological conditions and in modeling future states, general circulation models have not proved accurate enough to close water budgets in hydrological applications
production (NPP) is the primary conduit of carbon transfer from the atmosphere to the land surface and is thus a fundamental component of the global carbon cycle. In seasonally frozen environments, vegetation productivity is constrained by low temperatures and plant-available moisture for much of the year, while the active growing season is primarily determined by length of the nonfrozen period ( Jarvis and Linder 2000 ; Kimball et al. 2004 ). Boreal forest and arctic tundra biomes of the northern high
production (NPP) is the primary conduit of carbon transfer from the atmosphere to the land surface and is thus a fundamental component of the global carbon cycle. In seasonally frozen environments, vegetation productivity is constrained by low temperatures and plant-available moisture for much of the year, while the active growing season is primarily determined by length of the nonfrozen period ( Jarvis and Linder 2000 ; Kimball et al. 2004 ). Boreal forest and arctic tundra biomes of the northern high
could substantially affect atmospheric concentrations of CO 2 ( McGuire et al. 2006 ). However, increased vegetation growth in response to warming has the potential to mitigate the release of carbon from high-latitude soils ( McGuire et al. 1992 ; Shaver et al. 1992 ). Analyses based on remote sensing approaches that use a 20-yr record of satellite data indicate that the tundra is greening in the Arctic, suggesting an increase in photosynthetic activity and net primary production ( Sitch et al
could substantially affect atmospheric concentrations of CO 2 ( McGuire et al. 2006 ). However, increased vegetation growth in response to warming has the potential to mitigate the release of carbon from high-latitude soils ( McGuire et al. 1992 ; Shaver et al. 1992 ). Analyses based on remote sensing approaches that use a 20-yr record of satellite data indicate that the tundra is greening in the Arctic, suggesting an increase in photosynthetic activity and net primary production ( Sitch et al
simulation results may serve as a basis for projections of changes in landscape dynamics and consequent recommendations for policy development. The primary goal of the Western Arctic Linkage Experiment (WALE) was to evaluate uncertainties in regional hydrology and carbon estimates in Alaska and the adjacent Yukon Territory associated with 1) alternative driving datasets and 2) alternative simulation models ( McGuire 2006 , manuscript submitted to Earth Interactions , hereafter MCG). The sensitivity of
simulation results may serve as a basis for projections of changes in landscape dynamics and consequent recommendations for policy development. The primary goal of the Western Arctic Linkage Experiment (WALE) was to evaluate uncertainties in regional hydrology and carbon estimates in Alaska and the adjacent Yukon Territory associated with 1) alternative driving datasets and 2) alternative simulation models ( McGuire 2006 , manuscript submitted to Earth Interactions , hereafter MCG). The sensitivity of
