Error reduction for different prior flux errors. Test of the flux error reduction for different prior states in scenario 1 using 12 towers with 1 ppm observation error at each tower (Table 1). The Root Mean Square Error (RMSE-B) and Spatial Correlation Length (SCL) of the prior flux error in the default case (R) are 2 μmol m^–2 s^–1 and 5 km, respectively. The RMSE-B is varied as (A) 1 μmol m^–2 s^–1 and (B) 4 μmol m^–2 s^–1, and the SCL is varied as (C) 2 km and (D) 8 km. The domain and coordinates in each panel are same as Figure 1. DOI: https://doi.org/10.1525/elementa.138.f5