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Large‐Scale Controls of the Surface Water Balance Over Land: Insights From a Systematic Review and Meta‐Analysis
Author(s) -
Padrón Ryan S.,
Gudmundsson Lukas,
Greve Peter,
Seneviratne Sonia I.
Publication year - 2017
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1002/2017wr021215
Subject(s) - evapotranspiration , surface runoff , environmental science , water balance , precipitation , watershed , aridity index , vegetation (pathology) , hydrology (agriculture) , scale (ratio) , arid , land use , variance (accounting) , climatology , physical geography , geography , meteorology , ecology , cartography , geology , computer science , medicine , geotechnical engineering , accounting , pathology , machine learning , business , biology
The long‐term surface water balance over land is described by the partitioning of precipitation (P) into runoff and evapotranspiration (ET), and is commonly characterized by the ratio ET/P. The ratio between potential evapotranspiration (PET) and P is explicitly considered to be the primary control of ET/P within the Budyko framework, whereas all other controls are often integrated into a single parameter, ω. Although the joint effect of these additional controlling factors of ET/P can be significant, a detailed understanding of them is yet to be achieved. This study therefore introduces a new global data set for the long‐term mean partitioning of P into ET and runoff in 2,733 catchments, which is based on in situ observations and assembled from a systematic examination of peer‐reviewed studies. A total of 26 controls of ET/P that are proposed in the literature are assessed using the new data set. Results reveal that: (i) factors controlling ET/P vary between regions with different climate types; (ii) controls other than PET/P explain at least 35% of the ET/P variance in all regions, and up to ∼90% in arid climates; (iii) among these, climate factors and catchment slope dominate over other landscape characteristics; and (iv) despite the high attention that vegetation‐related indices receive as controls of ET/P, they are found to play a minor and often nonsignificant role. Overall, this study provides a comprehensive picture on factors controlling the partitioning of P, with valuable insights for model development, watershed management, and the assessment of water resources around the globe.