Implementing Dynamic Root Optimization in Noah-MP for Simulating Phreatophytic Root Water Uptake
Wu, Run-Jian Run-Jian
Pozdniakov, Sergey P.
Scott, Russell L.
AffiliationUniv Arizona, Dept Hydrol & Atmospher Sci
Univ Arizona, Biosphere 2
MetadataShow full item record
PublisherAMER GEOPHYSICAL UNION
CitationWang, P., Niu, G.‐Y., Fang, Y.‐H., Wu, R.‐J., Yu, J.‐J., Yuan, G.‐F., et al. (2018). Implementing dynamic root optimization in Noah‐MP for simulating phreatophytic root water uptake. Water Resources Research, 54, 1560–1575. https://doi.org/10.1002/2017WR021061
JournalWATER RESOURCES RESEARCH
Rights© 2018. American Geophysical Union. All Rights Reserved.
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at email@example.com.
AbstractWidely distributed in arid and semiarid regions, phreatophytic roots extend into the saturated zone and extract water directly from groundwater. In this paper, we implemented a vegetation optimality model of root dynamics (VOM-ROOT) in the Noah land surface model with multiparameterization options (Noah-MP LSM) to model the extraction of groundwater through phreatophytic roots at a riparian site with a hyperarid climate (with precipitation of 35 mm/yr) in northwestern China. VOM-ROOT numerically describes the natural optimization of the root profile in response to changes in subsurface water conditions. The coupled Noah-MP/VOM-ROOT model substantially improves the simulation of surface energy and water fluxes, particularly during the growing season, compared to the prescribed static root profile in the default Noah-MP. In the coupled model, more roots are required to grow into the saturated zone to meet transpiration demand when the groundwater level declines over the growing season. The modeling results indicate that at the study site, the modeled annual transpiration is 472 mm, accounting for 92.3% of the total evapotranspiration. Direct root water uptake from the capillary fringe and groundwater, which is supplied by lateral groundwater flow, accounts for approximately 84% of the total transpiration. This study demonstrates the importance of implementing a dynamic root scheme in a land surface model for adequately simulating phreatophytic root water uptake and the associated latent heat flux.
Note6 month embargo; published online: 20 February 2018
VersionFinal published version
SponsorsNational Natural Science Foundation of China [41671023, 41571029, 41271050]; NSFC-RFBR Program [41811130023, 18-55-53025 GammaPhiEH_a]; China Scholarship Council ; NASA MAP Program [80NSSC17K0352]; National Science Foundation for Critical Zone Observatory [NSF-EAR-1331408]; NSF Macrosystem Biology [NSF-EF 1065790]