5:15 PM - 7:15 PM
[ACG37-P02] Resolving Hillslope Land Cover Heterogeneity Improves Simulation of Terrestrial Energy and Water Budgets
Keywords:Hillslope hydrology, Land cover heterogeneity, Land surface model
Horizontal water transportation from hills to valleys widely dictates vegetation growth and modulates terrestrial water and energy budget. However, the complex land cover heterogeneity on hillslope was yet unprioritized and oversimplified in many land surface models (LSMs), despite its critical role in controlling terrestrial water and energy fluxes. Therefore, this study targets Africa and investigates the impact of explicitly representing hillslope water dynamics and land cover conditions in LSM on terrestrial water and energy budgets. To this end, a sub-grid approach named catchment-based strategy is implemented into LSM, where hillslope water dynamics and land cover heterogeneity are represented on discretized height bands of the representative hillslope. Through an array of experiments with different degree of complexity in representing water and vegetation heterogeneity along hillslope, the impact of representing them in LSM is evaluated and validated. Results show that representation of increasing heterogeneities amplifies the variability in simulated water and energy budgets, particularly in equatorial Africa. In addition to hill-to-valley water dynamics, representing vegetation distribution more realistically on hillslope to align with the differentiated soil water content (e.g., denser vegetation along riverside in arid region) significantly alters soil water content, runoff and evapotranspiration in near 5%, 7% and 18% of the African area, respectively. The new model better captured the hillslope-scale transpiration, with results more consistent with the observed discharge and leaf area index. Overall, LSM considering water dynamics and land cover heterogeneity along hillslope is proved to substantially modulate and better capture the terrestrial water and energy budgets.