The impacts of solar radiation variations on water and carbon cycles in Taiwan’s montane cloud-fog forest

Abstract:

Solar energy is a crucial driver to both hydrological and carbon-related processes on land. The change in solar radiation will affect evapotranspiration and correspondingly influence soil moisture and runoff. Besides, solar radiation is one of the controlling factors to the open of stomata and, thus, the CO₂ uptake. This study will focus on the effects of solar radiation variations on seasonal evapotranspiration and CO₂ uptake in Taiwan. We use ground-based observations over the montane cloud-fog forest and Himawari-8 satellite data to investigate the region where solar radiation has a larger seasonal variability. Idealized offline simulations in the Community Land Model will be further conducted to analyze water and carbon cycle response. Our preliminary results display a larger solar radiation variation, a combination of the frequent sunny and cloudy days, in summer compared to that in winter. In the idealized simulations, we compared two simulations using observational and climatological solar radiation forcing, respectively. The larger amount of evapotranspiration is shown when we use the climatological solar radiation forcing. This modelling results may also imply an overestimation in simulating water flux when considering the climatological forcing as the modelling strategy.