A convolution method to assess subgridâscale interactions between flow and patchy vegetation in biogeomorphic models
Gourgue, O.; van Belzen, J.; Schwarz, C.; Bouma, T.J.; van de Koppel, J.; Temmerman, S. (2021). A convolution method to assess subgridâscale interactions between flow and patchy vegetation in biogeomorphic models. J. Adv. Model. Earth Syst. 13(2): e2020MS002116. https://doi.org/10.1029/2020MS002116
Additional data:
In: Journal of Advances in Modeling Earth Systems. American Geophysical Union: Washington. e-ISSN 1942-2466, more
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Abstract |
Interactions between water flow and patchy vegetation are governing the functioning of many ecosystems. Yet, numerical models that simulate those interactions explicitly at the submeter patch scale to predict geomorphological and ecological consequences at the landscape scale (order of km2) are still very computationally demanding. Here, we present a novel and efficient convolution technique to incorporate biogeomorphic feedbacks in numerical models across multiple spatial scales (from less than 1âm2 to several km2). This new methodology allows for spatially refining coarseâresolution hydrodynamic simulations of flow velocities (order of m) around fineâresolution patchy vegetation patterns (order of 10âcm). Although flow perturbations around each vegetation grid cell are not simulated with the same level of accuracy as with more expensive finerâresolution models, we show that our approach enables spatial refinement of coarseâresolution hydrodynamic models by resolving efficiently subgridâscale flow velocity patterns within and around vegetation patches (mean error, spatial variability, and spatial correlation improved by, respectively, 13%, 66%, and 49% on average in our test cases). We also provide evidence that our approach can substantially improve the representation of important biogeomorphic processes, such as subgridâscale effects on net sedimentation rate and habitable surface area for vegetation (respectively 66% and 39% better on average). Finally, we estimate that replacing a fineâresolution model by a coarserâresolution model associated with the convolution method could reduce the computational time of realâlife fluctuating flow simulations by several orders of magnitude. This marks an important step forward toward more computationally efficient multiscale biogeomorphic modeling. |
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