Gridded CO2 and CH4 Flux Estimates for pan-Arctic and Boreal Regions, 2003-2015

This record is for the dataset “ Gridded CO2 and CH4 Flux Estimates for pan-Arctic and Boreal Regions, 2003-2015” at https://doi.org/10.3334/ORNLDAAC/1367 This dataset provides gridded estimates of gross primary productivity (GPP), ecosystem respiration (Reco), net ecosystem CO2 exchange (NEE; GPP - Reco), and methane (CH4) emissions from tundra and boreal wetland soils, across the pan-Arctic and Boreal zone (>49 degrees north) at 1-km spatial resolution. The data were produced through simulations of the Arctic terrestrial carbon flux model (TCFM-Arctic) and are provided at the daily time step for the years 2003-2015. TCFM-Arctic uses a light-use efficiency approach driven by satellite estimates of FPAR (fraction of absorbed photosynthetically active radiation) to estimate GPP, and autotrophic respiration (Ra) is estimated as a fraction of GPP. Heterotrophic respiration (Rh) is estimated using decomposition rates with environmental constraints applied to three near-surface soil organic carbon (SOC) pools, and Reco is determined as the sum of Ra and Rh. Methane production is estimated using optimal CH4 production rates with environmental constraints applied to the labile carbon pool, and transfer of CH4 from the soil to the atmosphere is modeled through vegetation, soil diffusion, and water ebullition pathways. The data were calibrated and evaluated using >60 tower eddy covariance (EC) sites. Baseline carbon pools were initialized by continuously cycling (spinning-up) the model for 1,000 model years using recent climatology from 1985 to 2002 to reach a dynamic steady-state between estimated net primary productivity (NPP = GPP - autotrophic respiration) and surface SOC stocks. The TCFM-Arctic simulations were extended to the full Arctic-boreal domain at a 1-km spatial resolution using land cover maps representing high latitude vegetation communities. The data are provided in NetCDF and comma-separated values (CSV) formats. This dataset can be downloaded at https://doi.org/10.3334/ORNLDAAC/1367

本数据集记录为DOI: 10.3334/ORNLDAAC/1367下的《泛北极与寒带区域网格化CO₂和CH₄通量估算数据集（2003-2015年）》，下载链接为https://doi.org/10.3334/ORNLDAAC/1367。

该数据集提供了泛北极与寒带区域（北纬49°以北）的网格化估算数据，涵盖苔原与寒带湿地土壤的总初级生产力（GPP, Gross Primary Productivity）、生态系统呼吸（Reco, Ecosystem Respiration）、生态系统净CO₂交换（NEE, Net Ecosystem CO₂ Exchange，即GPP与Reco的差值）以及甲烷（CH₄）排放，空间分辨率为1千米。

本数据集通过北极陆地碳通量模型（TCFM-Arctic, Arctic Terrestrial Carbon Flux Model）模拟生成，时间步长为日尺度，覆盖2003至2015年。TCFM-Arctic采用光利用效率方法，以卫星反演的光合有效辐射吸收比率（FPAR, Fraction of Absorbed Photosynthetically Active Radiation）作为驱动数据估算总初级生产力，并将自养呼吸（Ra, Autotrophic Respiration）估算为总初级生产力的一定比例。异养呼吸（Rh, Heterotrophic Respiration）则通过分解速率结合环境约束，针对三个近地表土壤有机碳（SOC, Soil Organic Carbon）库进行估算，而生态系统呼吸为自养呼吸与异养呼吸之和。

甲烷产生量通过最优甲烷产生速率结合环境约束（作用于活性碳库）进行估算，甲烷从土壤向大气的传输则通过植被、土壤扩散以及水体冒泡三种途径进行模拟。

本数据集基于60余个涡度协方差（EC, Eddy Covariance）观测塔站点完成校准与验证。基准碳库的初始化过程为：使用1985-2002年的近地面气候数据，将模型连续自旋（spin-up）运行1000个模型年，使估算的净初级生产力（NPP, Net Primary Productivity，即GPP与自养呼吸的差值）与地表土壤有机碳储量达到动态稳态。

TCFM-Arctic模拟通过采用表征高纬度植被群落的土地覆盖图，将模拟范围扩展至全北极-寒带区域，空间分辨率保持1千米。

本数据集以NetCDF与逗号分隔值（CSV, Comma-Separated Values）格式提供，可通过https://doi.org/10.3334/ORNLDAAC/1367下载获取。