Impacts of Topography‐Driven Water Redistribution on Terrestrial Water Storage Change in California Through Ecosystem Responses

Abstract Lateral subsurface flow plays an essential role in sustaining the terrestrial ecosystem, but it is not explicitly represented in most Earth System Models. In this study, we implemented an explicit lateral saturated flow model into the E3SM land model (ELM). The model explicitly describes la...

Full description

Saved in:
Bibliographic Details
Main Authors: Xue‐Yan Zhang, Yuanhao Fang, Guo‐Yue Niu, Peter A. Troch, Bo Guo, L. Ruby Leung, Michael A. Brunke, Patrick Broxton, Xubin Zeng
Format: Article
Language:English
Published: Wiley 2024-02-01
Series:Water Resources Research
Subjects:
Online Access:https://doi.org/10.1029/2023WR035572
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1849422869515206656
author Xue‐Yan Zhang
Yuanhao Fang
Guo‐Yue Niu
Peter A. Troch
Bo Guo
L. Ruby Leung
Michael A. Brunke
Patrick Broxton
Xubin Zeng
author_facet Xue‐Yan Zhang
Yuanhao Fang
Guo‐Yue Niu
Peter A. Troch
Bo Guo
L. Ruby Leung
Michael A. Brunke
Patrick Broxton
Xubin Zeng
author_sort Xue‐Yan Zhang
collection DOAJ
description Abstract Lateral subsurface flow plays an essential role in sustaining the terrestrial ecosystem, but it is not explicitly represented in most Earth System Models. In this study, we implemented an explicit lateral saturated flow model into the E3SM land model (ELM). The model explicitly describes lateral flow in the saturated zone by representing, for each model grid, an idealized hillslope consisting of five hydrologically connected soil columns. We conducted three model experiments driven by 0.125° atmospheric forcing data during 1980–2015 over California using models of the default ELM, a modified version of ELM to enhance infiltration, and the model with the lateral saturated flow model. The simulated runoff, evapotranspiration, and terrestrial water storage anomaly (TWSA) from the three simulations were evaluated against available observations, and the model explicitly representing lateral flow performs best. The new model produces greater gridcell‐averaged evapotranspiration especially over the mountainous regions with moderate relief and seasonally dry climates. Most importantly, it improves the modeled seasonal variations, interannual variabilities, and the recent decadal decline of TWSA. Many of these improvements can be attributed to the enhanced ecosystem resilience to droughts as demonstrated by transpiration increases caused by lateral flow. Model sensitivity experiments suggest that subsurface runoff is most sensitive to the ratio between horizontal and vertical saturated hydraulic conductivity, followed by hillslope planforms (convergent, divergent, and uniform), number of columns, and lower boundary conditions. Future work should effectively characterize hillslopes in global models and explore the long‐term influences of lateral water movement on modeled biogeochemical cycle.
format Article
id doaj-art-85ef434819764d33a6518135e197ff42
institution Kabale University
issn 0043-1397
1944-7973
language English
publishDate 2024-02-01
publisher Wiley
record_format Article
series Water Resources Research
spelling doaj-art-85ef434819764d33a6518135e197ff422025-08-20T03:30:53ZengWileyWater Resources Research0043-13971944-79732024-02-01602n/an/a10.1029/2023WR035572Impacts of Topography‐Driven Water Redistribution on Terrestrial Water Storage Change in California Through Ecosystem ResponsesXue‐Yan Zhang0Yuanhao Fang1Guo‐Yue Niu2Peter A. Troch3Bo Guo4L. Ruby Leung5Michael A. Brunke6Patrick Broxton7Xubin Zeng8Department of Hydrology and Atmospheric Sciences The University of Arizona Tucson AZ USADepartment of Hydrology and Atmospheric Sciences The University of Arizona Tucson AZ USADepartment of Hydrology and Atmospheric Sciences The University of Arizona Tucson AZ USADepartment of Hydrology and Atmospheric Sciences The University of Arizona Tucson AZ USADepartment of Hydrology and Atmospheric Sciences The University of Arizona Tucson AZ USAAtmospheric Sciences and Global Change Division Pacific Northwest National Laboratory Richland WA USADepartment of Hydrology and Atmospheric Sciences The University of Arizona Tucson AZ USASchool of Natural Resources and the Environment University of Arizona Tucson AZ USADepartment of Hydrology and Atmospheric Sciences The University of Arizona Tucson AZ USAAbstract Lateral subsurface flow plays an essential role in sustaining the terrestrial ecosystem, but it is not explicitly represented in most Earth System Models. In this study, we implemented an explicit lateral saturated flow model into the E3SM land model (ELM). The model explicitly describes lateral flow in the saturated zone by representing, for each model grid, an idealized hillslope consisting of five hydrologically connected soil columns. We conducted three model experiments driven by 0.125° atmospheric forcing data during 1980–2015 over California using models of the default ELM, a modified version of ELM to enhance infiltration, and the model with the lateral saturated flow model. The simulated runoff, evapotranspiration, and terrestrial water storage anomaly (TWSA) from the three simulations were evaluated against available observations, and the model explicitly representing lateral flow performs best. The new model produces greater gridcell‐averaged evapotranspiration especially over the mountainous regions with moderate relief and seasonally dry climates. Most importantly, it improves the modeled seasonal variations, interannual variabilities, and the recent decadal decline of TWSA. Many of these improvements can be attributed to the enhanced ecosystem resilience to droughts as demonstrated by transpiration increases caused by lateral flow. Model sensitivity experiments suggest that subsurface runoff is most sensitive to the ratio between horizontal and vertical saturated hydraulic conductivity, followed by hillslope planforms (convergent, divergent, and uniform), number of columns, and lower boundary conditions. Future work should effectively characterize hillslopes in global models and explore the long‐term influences of lateral water movement on modeled biogeochemical cycle.https://doi.org/10.1029/2023WR035572lateral flowecosystem resiliencedrought responsesEarth system models
spellingShingle Xue‐Yan Zhang
Yuanhao Fang
Guo‐Yue Niu
Peter A. Troch
Bo Guo
L. Ruby Leung
Michael A. Brunke
Patrick Broxton
Xubin Zeng
Impacts of Topography‐Driven Water Redistribution on Terrestrial Water Storage Change in California Through Ecosystem Responses
Water Resources Research
lateral flow
ecosystem resilience
drought responses
Earth system models
title Impacts of Topography‐Driven Water Redistribution on Terrestrial Water Storage Change in California Through Ecosystem Responses
title_full Impacts of Topography‐Driven Water Redistribution on Terrestrial Water Storage Change in California Through Ecosystem Responses
title_fullStr Impacts of Topography‐Driven Water Redistribution on Terrestrial Water Storage Change in California Through Ecosystem Responses
title_full_unstemmed Impacts of Topography‐Driven Water Redistribution on Terrestrial Water Storage Change in California Through Ecosystem Responses
title_short Impacts of Topography‐Driven Water Redistribution on Terrestrial Water Storage Change in California Through Ecosystem Responses
title_sort impacts of topography driven water redistribution on terrestrial water storage change in california through ecosystem responses
topic lateral flow
ecosystem resilience
drought responses
Earth system models
url https://doi.org/10.1029/2023WR035572
work_keys_str_mv AT xueyanzhang impactsoftopographydrivenwaterredistributiononterrestrialwaterstoragechangeincaliforniathroughecosystemresponses
AT yuanhaofang impactsoftopographydrivenwaterredistributiononterrestrialwaterstoragechangeincaliforniathroughecosystemresponses
AT guoyueniu impactsoftopographydrivenwaterredistributiononterrestrialwaterstoragechangeincaliforniathroughecosystemresponses
AT peteratroch impactsoftopographydrivenwaterredistributiononterrestrialwaterstoragechangeincaliforniathroughecosystemresponses
AT boguo impactsoftopographydrivenwaterredistributiononterrestrialwaterstoragechangeincaliforniathroughecosystemresponses
AT lrubyleung impactsoftopographydrivenwaterredistributiononterrestrialwaterstoragechangeincaliforniathroughecosystemresponses
AT michaelabrunke impactsoftopographydrivenwaterredistributiononterrestrialwaterstoragechangeincaliforniathroughecosystemresponses
AT patrickbroxton impactsoftopographydrivenwaterredistributiononterrestrialwaterstoragechangeincaliforniathroughecosystemresponses
AT xubinzeng impactsoftopographydrivenwaterredistributiononterrestrialwaterstoragechangeincaliforniathroughecosystemresponses