Numerical Simulation of CO₂ Concentrations in East Asia with RAMS-CMAQ

Abstract

The regional air quality modeling system RAMS-CMAQ (Regional Atmospheric Modeling System and Models-3 Community Multi-scale Air Quality) was developed by incorporating a vegetation photosynthesis and respiration module (VPRM) and used to simulate temporal-spatial variations in atmospheric CO₂ concentrations in East Asia, with prescribed surface CO₂ fluxes (i.e., fossil fuel emission, biomass burning, sea-air CO₂ exchange, and terrestrial biosphere CO₂ flux). Comparison of modeled CO₂ mixing ratios with eight ground-based in-situ measurements demonstrated that the model was able to capture most observed CO₂ temporal-spatial features. Simulated CO₂ concentrations were generally in good agreement with observed concentrations. Results indicated that the accumulated impacts of anthropogenic emissions contributed more to increased CO₂ concentrations in urban regions relative to remote locations. More-over, RAMS-CMAQ analysis demonstrates that surface CO₂ concentrations in East Asia are strongly influenced by terrestrial ecosystems.

Keywords:

• CO₂ concentration
• biospheric CO₂ flux
• carbon flux
• regional chemical transport model