Abstract In this study, we investigate the characteristics of stratosphere‐troposphere exchange (STE) of ozone and carbon monoxide (CO) over the North Pacific on the 350 K isentropic surface during 2005–2021 using two chemical reanalyses (Copernicus Atmosphere Monitoring Service and TCR‐2). Distinct dynamic controls on the STE processes were revealed. Equatorward anticyclonic (LC1)‐type Rossby wave breaking (RWB) dominated stratosphere‐to‐troposphere transport (STT), poleward cyclonic (P1)‐type RWB dominated troposphere‐to‐stratosphere transport (TST), and equatorward cyclonic (LC2)‐type RWB rarely induced STE. Notably, poleward anticyclonic (P2)‐type RWB, despite their primary association with TST, also caused significant STT, accounting for 36% of total TST cases and 30% of total STT cases. Seasonality analysis revealed that the ozone STT and CO TST peaked in summer and were the weakest in the winter and fall. Analysis of the geographical distribution within the Northern Pacific revealed that ozone STT hotspots were concentrated over the central and eastern Pacific, whereas the CO TST tended to occur further north, exhibiting two core regions on both sides of the North Pacific in summer. Interannual variability highlights a decrease in the total ozone STT, in contrast to an increase in the total CO TST. Despite slight systematic differences, both data sets demonstrated high spatiotemporal consistency in long‐term averages. We summarize the complicated relationship among the different types of RWBs, the direction of transport across the tropopause, and two different chemical components over the mid‐latitude North Pacific to advance our understanding of the chemical‐dynamical coupling in the STE and provide critical insights toward improving chemical‐climate modeling.
Xi et al. (Wed,) studied this question.