Large Differences in Global and Regional Total Soil Carbon Stock Estimates Based on SoilGrids, HWSD, and NCSCD: Intercomparison and Evaluation Based on Field Data From USA, England, Wales, and France
Large Differences in Global and Regional Total Soil Carbon Stock Estimates Based on SoilGrids, HWSD, and NCSCD: Intercomparison and Evaluation Based on Field Data From USA, England, Wales, and France
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DOI：
10.1002/2017gb005678
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发表时间：
2018-01
影响因子：
5.2
通讯作者：
M. Tifafi;B. Guenet;C. Hatté
中科院分区：
文献类型：
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作者：
M. Tifafi;B. Guenet;C. Hatté
土壤是陆地生态系统的主要组成部分，也是地球上最大的有机碳库。然而，它们是一种不可再生的自然资源，特别容易受到人类干扰和气候变化的影响。尽管土壤碳动态很重要，但它是未来气候预测不确定性的重要来源，并且越来越需要更精确的信息，以更好地了解控制土壤碳动态的机制并更好地约束地球系统模型。我们工作的目的是比较现有不同全球和区域数据库给出的土壤有机碳储量。我们计算了三个现有数据库（SoilGrids、协调世界土壤数据库和北环极地土壤碳数据库）给出的 1 m 深度的全球和区域土壤碳储量。我们观察到，每种产品预测的总库存差异很大：SoilGrids 估计约为 3,400 Pg，根据世界土壤协调数据库估计约为 2,500 Pg。这种差异在北方地区尤其明显，这些地区的差异可能与土壤有机碳浓度的巨大差异有关。其他地区的差异更为有限，可能与堆积密度估计值的差异有关。最后，对三个数据集与地面实况数据的评估表明，(i) 地面实况数据和比较数据集之间的空间模式存在显着差异，(ii) 与现场数据相比，数据集低估了 40% 以上的土壤有机碳储量。
Soils are the major component of the terrestrial ecosystem and the largest organic carbon reservoir on Earth. However, they are a nonrenewable natural resource and especially reactive to human disturbance and climate change. Despite its importance, soil carbon dynamics is an important source of uncertainty for future climate predictions and there is a growing need for more precise information to better understand the mechanisms controlling soil carbon dynamics and better constrain Earth system models. The aim of our work is to compare soil organic carbon stocks given by different global and regional databases that already exist. We calculated global and regional soil carbon stocks at 1 m depth given by three existing databases (SoilGrids, the Harmonized World Soil Database, and the Northern Circumpolar Soil Carbon Database). We observed that total stocks predicted by each product differ greatly: it is estimated to be around 3,400 Pg by SoilGrids and is about 2,500 Pg according to Harmonized World Soil Database. This difference is marked in particular for boreal regions where differences can be related to high disparities in soil organic carbon concentration. Differences in other regions are more limited and may be related to differences in bulk density estimates. Finally, evaluation of the three data sets versus ground truth data shows that (i) there is a significant difference in spatial patterns between ground truth data and compared data sets and that (ii) data sets underestimate by more than 40% the soil organic carbon stock compared to field data.