Fig. 6
a 31-day running median CO2 difference between Towers 09 and Tower 01 for 2014 (black line) and composited for 2013–2018 (shaded area), with the width of the shaded area indicating the standard deviation amongst years. Data for which either Tower 01 or Tower 09 were influenced by the urban plume were excluded from the analysis. b Predicted seasonal pattern of difference in CO2 mole fraction (dimensionless, see Eq. 2) between Tower 01 and Tower 09, based on typical forest, corn and soy fluxes shown in Fig. 2a, and forest and agricultural land cover differences within 10 km of each site, between the two sites. c Forward modelled (using Hestia and VPRM) 31-day running median CO2 difference (black) between Towers 09 and 01 for 2014. Difference between observed and modelled Tower 01–Tower 09 difference is shown in gray