Figure
S3. Observed tracer seasonal cycles, reconstructed for three ACT regions
and from five ACT campaigns shown in Figure 1. (Top Row) Observations
are partitioned as atmospheric boundary layer (PBL) and free troposhere
(FT) using on-board thermodynamics and lidar data. (Bottom Row) Tracer
enhancements shown as difference between individual BL samples and
seasonal-regional averaged FT samples (BL – \(\overline{\text{FT}}\)).
Positive/negative values indicate higher/lower CO2 in
the BL relative to the FT. Error bars represent the standard error
across individual flask samples.