Tall tower CO₂ concentration simulation using the WRF-STILT model

By using high spatial and temporal resolution EDGAR fossil emissions (13 categories) and Carbon Tracker NEE flux, WRF-STILT model was evaluated with one year (2008) CO₂ concentration observations at a homogeneous agricultural underlying surface, which located in U.S. corn belt. The results showed that this model could capture the strong seasonal and daily variation, with RMSE be 10.6×10^-6, R=0.44(n=7784, P<0.001). The linear regression slope of growing season concentration enhancement was 1.08(R=0.52, P<0.001), indicating high consistency, while the intercept (7.26×10^-6) reflects the overestimation of fossil emission or underestimation of NEE. During this year round, observed enhancement was 4.83×10^-6, smaller than sum of the fossil enhancement contribution (6.61×10^-6) and NEE contribution (3.23×10^-6). The oil production and refineries and energy industry contributed 2.55×10^-6 (38.6%) and 1.43×10^-6 (21.6%) of all fossil enhancements, separately. Biomass burning only contributes 0.06×10^-6 to the total enhancement which was ignorable compared with fossil and NEE. At the end, it can be concluded that this method can be used to retrieve regional scale greenhouse gas flux in China.