Towards improved global estimates and model representations of water storage in the unsaturated zone

Abstract The unsaturated zone is a globally important, dynamic water store, which affects resources, agriculture and pollutant transport. Despite this, the magnitude of storage remains highly uncertain. This work provides first global estimates this store (1.0 x10 5 km 3 ) in comparison to recent modern groundwater (3.5x10 ), before presenting roadmap for improved representation hydrological models.