NACP MsTMIP: Unified North American Soil Map

This data set provides soil maps for the United States (US) (including Alaska), Canada, Mexico, and a part of Guatemala. The map information content includes maximum soil depth and eight soil attributes including sand, silt, and clay content, gravel content, organic carbon content, pH, cation exchange capacity, and bulk density for the topsoil layer (0-30 cm) and the subsoil layer (30-100 cm). The spatial resolution is 0.25 degree.

The Unified North American Soil Map (UNASM) combined information from the state-of-the-art US General Soil Map (STATSGO2) and Soil Landscape of Canada (SLCs) databases. The area not covered by these data sets was filled by using the Harmonized World Soil Database version 1.21 (HWSD1.21). The Northern Circumpolar Soil Carbon (NCSCD) database was used to provide more accurate and up-to-date soil organic carbon information for the high-latitude permafrost region and was combined with soil organic carbon content derived from the UNASM (Liu et al., 2013).

The UNASM data were utilized in the North American Carbon Program (NACP) Multi-Scale Synthesis and Terrestrial Model Intercomparison Project (MsTMIP) as model input driver data (Huntzinger et al., 2013). The driver data were used by 22 terrestrial biosphere models to run baseline and sensitivity simulations. The compilation of these data was facilitated by the NACP Modeling and Synthesis Thematic Data Center (MAST-DC). MAST-DC was a component of the NACP (www.nacarbon.org) designed to support NACP by providing data products and data management services needed for modeling and synthesis activities.

本数据集为美国（含阿拉斯加）、加拿大、墨西哥及危地马拉部分区域提供土壤图谱。图谱信息涵盖表层（0~30cm）与亚表层（30~100cm）土壤的最大土层深度，以及砂粒含量、粉粒含量、黏粒含量、砾石含量、有机碳含量、pH值、阳离子交换量、容重共8项土壤属性，空间分辨率为0.25度。

统一北美土壤图谱（Unified North American Soil Map, UNASM）整合了当前顶尖的美国通用土壤图谱（STATSGO2）与加拿大土壤景观（Soil Landscape of Canada, SLCs）数据库的相关数据。上述两类数据集未覆盖的区域，采用世界土壤数据库和谐版1.21（Harmonized World Soil Database version 1.21, HWSD1.21）进行补全。针对高纬度永久冻土区域，研究采用环北极土壤碳数据库（Northern Circumpolar Soil Carbon Database, NCSCD）以获取更精准且时效性更强的土壤有机碳信息，并将其与UNASM反演得到的土壤有机碳含量相结合（Liu等，2013）。

UNASM数据曾作为模型输入驱动数据，应用于北美碳计划（North American Carbon Program, NACP）多尺度综合与陆地模型比对项目（Multi-Scale Synthesis and Terrestrial Model Intercomparison Project, MsTMIP）（Huntzinger等，2013）。该驱动数据被22个陆地生物圈模型用于开展基准模拟与敏感性试验。本数据集的整编工作由NACP建模与综合主题数据中心（NACP Modeling and Synthesis Thematic Data Center, MAST-DC）统筹完成。MAST-DC是NACP的下属分支机构（官网：www.nacarbon.org），其通过提供建模与综合研究所需的数据产品及数据管理服务，为NACP的相关活动提供支撑。