Close up of the high-resolution profile of methane in the lower troposphere below 5 km. Black dots represent our median retrieved values with their associated error bars. Blue diamonds and bars represent methane mixing ratios reported by Niemann et al. (2010) and their standard deviation, respectively. Red horizontal dashed lines labeled A, B, and C represent the altitude of the boundary layers identified in Charnay & Lebonnois (2012) at 300 m, 800 m, and 2 km, respectively.