Multi-variate validation of a high-resolution application of the Community Land Model (CLM5) in Ghana

Study region: Ghana, West Africa, spanning strong hydroclimatic gradients from humid tropical forests in the south-west to savannah-dominated drylands in the north under the influence of the West African monsoon.

Study focus: This study evaluates a 1 km application of the Community Land Model version 5 (CLM5) in simulating land–atmosphere processes across Ghana. The model is driven by ERA5 meteorological forcing and uses MODIS land cover and SoilGrids soil properties. Simulations are evaluated against 23 soil moisture stations, four eddy covariance flux sites, streamflow from four catchments, and derived gross primary production (GPP).

New hydrological insights: CLM5 reproduces major spatial gradients and seasonal cycles of soil moisture, energy fluxes, GPP, and runoff, including wetter southwest conditions and a northward transition to more seasonal, water-limited regimes in Ghana. It captures wet season increases in latent heat flux and GPP and higher sensible heat flux during dry periods. However, systematic biases persist, including soil moisture overestimation, dry-season underestimation of GPP, and mixed latent and sensible heat flux errors across sites. ... mehrRunoff simulations reproduce seasonality but underestimate streamflow and show weak agreement with observations. These limitations likely reflect uncertainties in precipitation forcing, soil hydraulic properties, vegetation representation, and simplified runoff processes. Overall, CLM5 demonstrates strong capability for representing regional land-surface dynamics in West Africa, but improvements in forcing data and process representations are needed to enhance performance in data-sparse tropical regions. The results support potential applications in hydrological assessment, agricultural planning, and climate resilience strategies.