GLobal HYdrogeology MaPS (GLHYMPS) of permeability and porosity

The lack of robust, spatially distributed subsurface data is the key obstacle limiting the implementation of complex and realistic groundwater dynamics into global land surface, hydrologic, and climate models. We map and analyze permeability and porosity globally and at high resolution for the first time. The new permeability and porosity maps are based on a recently completed high-resolution global lithology map that differentiates fine and coarse-grained sediments and sedimentary rocks, which is important since these have different permeabilities. The average polygon size in the new map is ~100 km2, which is a more than hundredfold increase in resolution compared to the previous map which has an average polygon size of ~14,000 km2. We also significantly improve the representation in regions of weathered tropical soils and permafrost. The spatially distributed mean global permeability ~10-15m2 with permafrost or ~1014m2 without permafrost. The spatially distributed mean porosity of the globe is 14%. The maps will enable further integration of groundwater dynamics into land surface, hydrologic, and climate models.

缺乏鲁棒性强、空间分布完整的地下数据（subsurface data），是制约将复杂且符合实际的地下水动力过程纳入全球陆面、水文与气候模型的核心障碍。本研究首次实现了全球范围的高分辨率渗透率（permeability）与孔隙率（porosity）制图与分析。本次构建的渗透率与孔隙率图集，基于最新完成的高分辨率全球岩性图（lithology map），该图集可区分细粒与粗粒沉积物及沉积岩——由于不同类型沉积物与沉积岩的渗透率存在显著差异，这一区分至关重要。新图集的平均多边形面积约为100 km²，相较于此前平均多边形面积约14000 km²的旧版图集，空间分辨率提升了百余倍。本研究还显著优化了风化热带土壤与永久冻土（permafrost）区域的参数表征效果。全球空间分布的平均渗透率在含永久冻土区域约为10⁻¹⁵ m²，不含永久冻土区域约为10¹⁴ m²；全球整体空间分布的平均孔隙率为14%。上述图集将推动地下水动力过程进一步融入陆面、水文与气候模型。