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Abstract. Fire causes abrupt changes in vegetation properties and modifies fluxexchanges between land and atmosphere at subseasonal to seasonal scales. Yetthese short-term fire effects on vegetation dynamics and surface energybalance have not been comprehensively investigated in the fire-coupledvegetation model. This study applies the SSiB4/TRIFFID-Fire (the SimplifiedSimple Biosphere Model coupled with the Top-down Representation of InteractiveFoliage and Flora Including Dynamics with fire) model to studythe short-term fire impact in southern Africa. Specifically, we aim toquantify how large impacts fire exerts on surface energy throughdisturbances on vegetation dynamics, how fire effects evolve during the fireseason and the subsequent rainy season, and how surface-darkening effectsplay a role besides the vegetation change effects. We find fire causes an annual average reduction in grass cover by 4 %–8 %for widespread areas between 5–20∘ S and a tree cover reductionby 1 % at the southern periphery of tropical rainforests. The regionalfire effects accumulate during June–October and peak in November, thebeginning of the rainy season. After the fire season ends, the grass coverquickly returns to unburned conditions, while the tree fraction hardlyrecovers in one rainy season. The vegetation removal by fire has reduced theleaf area index (LAI) and gross primary productivity (GPP) by 3 %–5 % and5 %–7 % annually. The exposure of bare soil enhances surface albedo andtherefore decreases the absorption of shortwave radiation. Annual meansensible heat has dropped by 1.4 W m−2, while the latent heat reductionis small (0.1 W m−2) due to the compensating effects between canopytranspiration and soil evaporation. Surface temperature is increased by asmuch as 0.33 K due to the decrease of sensible heat fluxes, and the warmingwould be enhanced when the surface-darkening effect is incorporated. Ourresults suggest that fire effects in grass-dominant areas diminish within1 year due to the high resilience of grasses after fire. Yet fire effectsin the periphery of tropical forests are irreversible within one growingseason and can cause large-scale deforestation if accumulated for hundredsof years. 

Fire causes abrupt changes in vegetation properties and modifies flux exchanges between land and atmosphere at subseasonal to seasonal scales. Yet these shortterm fire effects on vegetation dynamics and surface energy balance have not been comprehensively investigated in the fire-coupled vegetation model. This study applies the SSiB4/TRIFFID-Fire (the Simplified Simple Biosphere Model coupled with the Top-down Representation of Interactive Foliage and Flora Including Dynamics with fire) model to study the short-term fire impact in southern Africa. Specifically, we aim to quantify how large impacts fire exerts on surface energy through disturbances on vegetation dynamics, how fire effects evolve during the fire season and the subsequent rainy season, and how surface-darkening effects play a role besides the vegetation change effects. We find fire causes an annual average reduction in grass cover by 4 %–8% for widespread areas between 5–20 S and a tree cover reduction by 1% at the southern periphery of tropical rainforests. The regional fire effects accumulate during June–October and peak in November, the beginning of the rainy season. After the fire season ends, the grass cover quickly returns to unburned conditions, while the tree fraction hardly recovers in one rainy season. The vegetation removal by fire has reduced the leaf area index (LAI) and gross primary productivity (GPP) by 3 %–5% and 5 %–7% annually. The exposure of bare soil enhances surface albedo and therefore decreases the absorption of shortwave radiation. Annual mean sensible heat has dropped by 1.4Wm−2, while the latent heat reduction is small (0.1Wm−2/ due to the evaporation. Surface temperature is increased by as much as 0.33K due to the decrease of sensible heat fluxes, and the warming would be enhanced when the surface-darkening effect is incorporated. Our results suggest that fire effects in grass-dominant areas diminish within 1 year due to the high resilience of grasses after fire. Yet fire effects in the periphery of tropical forests are irreversible within one growing season and can cause large-scale deforestation if accumulated for hundreds of years.