CE-QUAL-W2를 이용한 성층 저수지에서 CO₂의 시공간적 분포 및 물질수지 분석 = Characterizing Spatiotemporal Variations and Mass Balance of CO₂ in a Stratified Reservoir using CE-QUAL-W2

다국어 초록 (Multilingual Abstract)

Dam reservoirs have been reported to contribute significantly to global carbon emissions, but unlike natural lakes, there is considerable uncertainty in calculating carbon emissions due to the complex of emission pathways. In particular, the method of calculating carbon dioxide (CO₂) net atmospheric flux (NAF) based on a simple gas exchange theory from sporadic data has limitations in explaining the spatiotemporal variations in the CO2 flux in stratified reservoirs. This study was aimed to analyze the spatial and temporal CO₂ distribution and mass balance in Daecheong Reservoir, located in the mid-latitude monsoon climate zone, by applying a two-dimensional hydrodynamic and water quality model (CE-QUAL-W2). Simulation results showed that the Daecheong Reservoir is a heterotrophic system in which CO₂ is supersaturated as a whole and releases CO₂ to the atmosphere. Spatially, CO₂ emissions were greater in the lacustrine zone than in the riverine and transition zones. In terms of time, CO₂ emissions changed dynamically according to the temporal stratification structure of the reservoir and temporal variations of algae biomass. CO₂ emissions were greater at night than during the day and were seasonally greatest in winter. The CO₂ NAF calculated by the CE-QUAL-W2 model and the gas exchange theory showed a similar range, but there was a difference in the point of occurrence of the peak value. The findings provide useful information to improve the quantification of CO₂ emissions from reservoirs. In order to reduce the uncertainty in the estimation of reservoir carbon emissions, more precise monitoring in time and space is required.