This record is for the dataset “ Synthesis of Winter In Situ Soil CO2 Flux in pan-Arctic and Boreal Regions, 1989-2017” at <a href=" https://doi.org/10.3334/ORNLDAAC/1692">https://doi.org/10.3334/ORNLDAAC/1692</a><p><p> This dataset provides a synthesis of winter ( September-April) in situ soil CO2 flux measurement data from locations across pan-Arctic and Boreal permafrost regions. The in situ data were compiled from 66 published and 21 unpublished studies conducted from 1989-2017. The data sources (publication references) are provided. Sampling sites spanned pan-Arctic Boreal and tundra regions (>53 Deg N) in continuous, discontinuous, and isolated/sporadic permafrost zones. The CO2 flux measurements were aggregated at the monthly level, or seasonally when monthly data were not available, and are reported as the daily average (g C m-2 day-1) over the interval. Soil moisture and temperature data plus environmental and ecological model driver data (e.g., vegetation type and productivity, soil substrate availability) are also included based on gridded satellite remote sensing and reanalysis sources.<p>This dataset can be downloaded at <a href=" https://doi.org/10.3334/ORNLDAAC/1692">https://doi.org/10.3334/ORNLDAAC/1692</a>

This record is for the dataset “ ABoVE: Synthesis of Post-Fire Regeneration Across Boreal North America” at <a href= " https://doi.org/10.3334/ORNLDAAC/1955">https://doi.org/10.3334/ORNLDAAC/1955 </a>. <p><p>This dataset is a synthesis of species-specific pre- and post-fire tree stem density estimates, field plot characterization data, and acquired climate moisture deficit data for sites from Alaska, USA eastward to Quebec, Canada in fires that burned between 1989 and 2014. Data are from 1,538 sites across 58 fire perimeters encompassing 4.52 Mha of forest and all major boreal ecozones in North America. To be included in this synthesis, a site had to contain information on species-specific post-fire seedling densities. This included sites where seedlings had been counted 2-13 years post-fire, a timeframe over which there was little change in relative dominance of species based on densities. Plot characterization data includes stand age, site drainage, disturbance history, crown combustion severity, seedbed conditions, and stand structural attributes. Gridded values of Hargreaves Climate Moisture Deficit (CMD) were obtained for each plot where plot coordinates were available. These values included 30-year normals (1981-2010) and CMD in the two years immediately following the fire year. CMD anomalies were calculated as the difference between the 30-year normal and the single year values for each of the first two years after a fire. These synthesis data are provided in comma-separated values (CSV) format. <p>This dataset can be downloaded at <a href= " https://doi.org/10.3334/ORNLDAAC/1955">https://doi.org/10.3334/ORNLDAAC/1955 </a>.

This record is for the dataset “The ABCflux Database: Arctic-Boreal CO2 Flux and Site Environmental Data, 1989-2020 ” at <a href= " https://doi.org/10.3334/ORNLDAAC/1934"> https://doi.org/10.3334/ORNLDAAC/1934</a><p><p>This Arctic-Boreal CO2 fluxes (ABCflux) dataset contains monthly aggregates of terrestrial net ecosystem CO2 exchange and its derived partitioned component fluxes: gross primary productivity (GPP) and ecosystem respiration. Over 70 supporting variables describe key site conditions (e.g., vegetation and disturbance type), micrometeorological and environmental measurements (e.g., air and soil temperatures), and flux measurement techniques. The data contained in this ABCflux dataset form a standardized monthly database of Arctic-Boreal CO2 fluxes (i.e., ABCflux Database) and include 244 sites and 6,309 monthly observations; 136 sites and 2,217 monthly observations represent tundra, and 108 sites and 4,092 observations represent the boreal biome. The data are for the period 1989 to 2020. <p>This dataset can be downloaded at <a href= " https://doi.org/10.3334/ORNLDAAC/1934"> https://doi.org/10.3334/ORNLDAAC/1934</a>

This record is for the dataset “ The Boreal–Arctic Wetland and Lake Dataset (BAWLD)” at <a href= "https://doi.org/10.5194/essd-13-5127-2021 "> https://doi.org/10.5194/essd-13-5127-2021</a><p><p> Methane emissions from boreal and arctic wetlands, lakes, and rivers are expected to increase in response to warming and associated permafrost thaw. However, the lack of appropriate land cover datasets for scaling field-measured methane emissions to circumpolar scales has contributed to a large uncertainty for our understanding of present-day and future methane emissions. Here we present the Boreal–Arctic Wetland and Lake Dataset (BAWLD), a land cover dataset based on an expert assessment, extrapolated using random forest modelling from available spatial datasets of climate, topography, soils, permafrost conditions, vegetation, wetlands, and surface water extents and dynamics. In BAWLD, we estimate the fractional coverage of five wetland, seven lake, and three river classes within 0.5 × 0.5∘ grid cells that cover the northern boreal and tundra biomes (17 % of the global land surface). Land cover classes were defined using criteria that ensured distinct methane emissions among classes, as indicated by a co-developed comprehensive dataset of methane flux observations. In BAWLD, wetlands occupied 3.2 × 106 km2 (14 % of domain) with a 95 % confidence interval between 2.8 and 3.8 × 106 km2. Bog, fen, and permafrost bog were the most abundant wetland classes, covering ∼ 28 % each of the total wetland area, while the highest-methane-emitting marsh and tundra wetland classes occupied 5 % and 12 %, respectively. Lakes, defined to include all lentic open-water ecosystems regardless of size, covered 1.4 × 106 km2 (6 % of domain). Low-methane-emitting large lakes (>10 km2) and glacial lakes jointly represented 78 % of the total lake area, while high-emitting peatland and yedoma lakes covered 18 % and 4 %, respectively. Small (<0.1 km2) glacial, peatland, and yedoma lakes combined covered 17 % of the total lake area but contributed disproportionally to the overall spatial uncertainty in lake area with a 95 % confidence interval between 0.15 and 0.38 × 106 km2. Rivers and streams were estimated to cover 0.12  × 106 km2 (0.5 % of domain), of which 8 % was associated with high-methane-emitting headwaters that drain organic-rich landscapes. Distinct combinations of spatially co-occurring wetland and lake classes were identified across the BAWLD domain, allowing for the mapping of “wetscapes” that have characteristic methane emission magnitudes and sensitivities to climate change at regional scales. With BAWLD, we provide a dataset which avoids double-accounting of wetland, lake, and river extents and which includes confidence intervals for each land cover class. As such, BAWLD will be suitable for many hydrological and biogeochemical modelling and upscaling efforts for the northern boreal and arctic region, in particular those aimed at improving assessments of current and future methane emissions. Data are freely available at https://doi.org/10.18739/A2C824F9X (Olefeldt et al., 2021). <p>This dataset can be downloaded at <a href= "https://doi.org/10.5194/essd-13-5127-2021 "> https://doi.org/10.5194/essd-13-5127-2021</a>

This record is for the dataset “Dataset for Monthly Gridded Data Product of Northern Wetland Methane Emissions Based on Upscaling Eddy Covariance Observations” at <a href= "https://doi.org/10.5281/zenodo.2560164">https://doi.org/10.5281/zenodo.2560164</a>. <p><p> This dataset provides wetland methane (CH4) emissions, their uncertainties and underlying CH4 flux densities north from 45 N using three different wetland maps. The data products are derived using data from several eddy covariance CH4 flux sites, random forest machine learning algorithms and three prescribed wetland maps. The data are at 0.5 by 0.5 deg or 1 by 1 deg resolution, depending on the wetland map used. The dataset covers years 2013 and 2014. CH4 flux densities are provided only for grid cells with > 5 % wetland coverage. <p>The three data products are provided in netCDF format files (.nc). Please see more details in the attributes saved in the netCDF files.<p> <ul> RF-DYPTOP.ncUpscaling based on DYPTOP dynamic wetland map. At 1 by 1 deg resolution. <p>RF-GLWD.ncUpscaling using GLWD static wetland map. At 0.5 by 0.5 deg resolution. <p>RF-PEATMAP.ncUpscaling using PEATMAP static wetland map. At 0.5 by 0.5 deg resolution. </ul> <p>This data can be downloaded at <a href= "https://doi.org/10.5281/zenodo.2560164">https://doi.org/10.5281/zenodo.2560164</a>