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Spin‐up behavior and effects of initial conditions for an integrated hydrologic model
Author(s) -
Seck Alimatou,
Welty Claire,
Maxwell Reed M.
Publication year - 2015
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 - 10.1002/2014wr016371
Subject(s) - surface runoff , environmental science , groundwater recharge , precipitation , water storage , water table , moisture , hydrology (agriculture) , water content , range (aeronautics) , soil science , atmospheric sciences , meteorology , groundwater , geology , aquifer , materials science , geography , geotechnical engineering , ecology , geomorphology , inlet , biology , composite material
Initial conditions have been shown to have a strong effect on outputs of surface water models, but their impact on integrated hydrologic models is not well documented. We investigated the effects of initial conditions on an integrated hydrologic model of a 5632 km 2 domain in the northeastern U.S. Simulations were run for the year 1980 using four initial conditions spanning a range of average depth to water table, including 1 m (“wet”), 3m, 5m, and 7 m (“dry”) below land surface. Model outputs showed significant effects of initial conditions on basin‐averaged variables such as subsurface storage, surface storage, and surface runoff, with the greatest impact observed on surface storage and runoff. Effects of initial conditions were related to meteorological conditions, with precipitation reducing the effects of initial conditions on surface storage and runoff. Additionally, feedbacks between soil moisture and land‐energy fluxes affected the impacts of initial conditions: higher temperatures magnified the differences in storage, recharge, and discharge among the four initial‐condition scenarios. Ten year recursive runs were conducted for the wet and dry scenarios. Spin‐up times varied by model components and were considerably smaller for land‐surface states and fluxes. Spin‐up for dry initial conditions was slower than for wet initial conditions, indicating longer system memory for dry initial conditions. These variations in persistence of initial conditions should be taken into consideration when designing model initialization approaches. More broadly, this behavior is indicative of increased persistence of the effects of dry years as opposed to wet years in hydrologic systems.