The influence of two land‐surface hydrology schemes on the terrestrial carbon cycle of Africa: A regional climate model study

Abstract

AbstractTwo 16‐year simulations were conducted to study the influence of two runoff schemes [the default one is TOPMODEL (hereafter referred as TOP) and the other one is the variable infiltration capacity (VIC)] with vegetation is being interactive [by enabling the carbon–nitrogen (CN) module] on the terrestrial carbon cycle fluxes of Africa using the regional climate model—RegCM4. The first simulation was labelled as CN‐TOP, while the second simulation was hereafter referred to as CN‐VIC. The results were evaluated and compared against various observation‐based satellites and reanalysis products. Results showed that the CN‐TOP overestimates leaf area index (LAI) and slightly underestimates the terrestrial carbon fluxes in comparison with the reference product; meanwhile, the CN‐VIC severely underestimates both LAI and terrestrial fluxes particularly over the Congo basin. In addition, the CN‐VIC shows a superior performance for simulating the net ecosystem exchange (NEE) than when it is simulated by the CN‐TOP. In summary, the coupled RegCM4‐CLM45‐CN‐VIC model can be recommended for future studies of NEE over Africa. To obtain robust results for simulating the terrestrial carbon fluxes especially the NEE; it is highly recommended to calibrate the four parameters of the VIC surface data set over Africa particularly over the Congo basin against in‐situ observations.