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A New Perspective on Terrestrial Hydrologic Intensity That Incorporates Atmospheric Water Demand
Author(s) -
Ficklin Darren L.,
Abatzoglou John T.,
Novick Kimberly A.
Publication year - 2019
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2019gl084015
Subject(s) - precipitation , environmental science , intensity (physics) , index (typography) , hydrological modelling , supply and demand , climatology , meteorology , atmospheric sciences , hydrology (agriculture) , economics , geography , computer science , geology , physics , quantum mechanics , geotechnical engineering , world wide web , microeconomics
Abstract Hydrologic intensity is often quantified using precipitation without directly incorporating atmospheric water demand. We develop a hydrologic intensity index called the surplus deficit intensity (SDI) index that accounts for variation in supply and demand. SDI is the standardized sum of standardized surplus intensity (mean of daily surplus when supply > demand) and deficit time (mean of consecutive days when demand > supply). Using an observational ensemble of global daily precipitation and atmospheric water demand during 1979–2017, we document widespread hydrologic intensification (SDI; +0.11 z ‐score per decade) driven primarily by increased surplus intensity. Using a climate model ensemble of the United States, hydrologic intensification is projected for the mid‐21st century (+0.86 in z ‐score compared to 1971–2000), producing greater apparent intensification when compared to an index that does not explicitly incorporate demand. While incorporating demand had a minor effect on observed hydrologic intensification, it doubles hydrological intensification for the mid‐21st century.