Fig. 4From: An empirical model for estimating daily atmospheric column-averaged CO2 concentration above São Paulo state, Brazila Cross-validation between \({\text{X}}_{{{\text{CO}}_{{2}} }}\) estimated by stepwise and \({\text{X}}_{{{\text{CO}}_{{2}} }}\) observed by OCO-2 and b Daily downscale of natural \({\text{X}}_{{{\text{CO}}_{{2}} }}\) using Eq. 1 and daily measurements of NASA/POWER from January 2015 to December 2019Back to article page