Читать книгу Congo Basin Hydrology, Climate, and Biogeochemistry - Группа авторов - Страница 71

Using hydrological models, Getirana et al. (2017a) decomposed the TWS variability into its four major components: surface water storage (SWS), groundwater storage (GWS), soil moisture (SM), and snow water equivalent (SWE). Two state of‐the‐art models, the Noah land surface model (LSM) with multi‐parameterization options (Noah‐MP Niu et al., 2011) and the Hydrological Modeling and Analysis Platform (HyMAP) river routing scheme (Getirana et al., 2012, 2017b), are combined in order to represent the physical processes controlling TWS dynamics. Noah‐MP is a multi‐physics version of the community Noah LSM (Ek et al., 2003). As in most LSMs, Noah‐MP maintains surface energy and water balances while simulating direct evaporation from soil, transpiration from vegetation, evaporation of interception and snow sublimation, and estimating key surface energy and moisture prognostics such as land surface temperature, snowpack, soil moisture and soil temperature. In addition, Noah‐MP incorporates a three‐layer snow physics component and a groundwater module with a prognostic water table (Niu et al., 2011). HyMAP is a state‐of‐the‐art global scale river routing scheme capable of simulating surface water dynamics in both rivers and floodplains using the local inertia formulation (Bates et al., 2010; Getirana et al., 2017b), derived from the full hydrodynamic equations. The local inertia formulation accounts for a more stable and computationally efficient representation of river flow diffusiveness, essential for a physically based representation of wetlands, floodplains, and backwater effects. Noah‐MP and HyMAP are one‐way coupled. This means that, at each time step, gridded surface runoff and baseflow output from Noah‐MP are transferred to HyMAP and used to simulate spatially continuous surface water dynamics. No information is returned from HyMAP to Noah‐MP. Several meteorological and precipitation datasets were used as model inputs, resulting in a 12‐member ensemble model output. Here, the ensemble mean is used as the reference. The output from this model is used in this study as a surrogate for the

SWS over the Congo Basin.