资源环境科技发展态势分析平台

Iodine compounds destroy ozone (O₃) in the global troposphere and form new aerosols, thereby affecting the global radiative balance. However, few reports have described the latitudinal distribution of atmospheric iodine compounds. This work reports iodine monoxide (IO) measurements taken over unprecedented sampling areas from the Arctic to the Southern Hemisphere and spanning sea surface temperatures (SSTs) of approximately 0 to 31.5 ^∘C. The highest IO concentrations were observed over the Western Pacific warm pool (WPWP), where O₃ minima were also measured. There, a negative correlation was found between O₃ and IO mixing ratios at extremely low O₃ concentrations. This correlation is not explained readily by the O₃-dependent oceanic fluxes of photolabile inorganic iodine compounds, which is the dominant source in recent global-scale chemistry transport models representing iodine chemistry. Actually, the correlation rather implies that O₃-independent pathways can be similarly important in the WPWP. The O₃-independent fluxes result in a 15 % greater O₃ loss than that estimated for O₃-dependent processes alone. The daily O₃ loss rate related to iodine over the WPWP is as high as approximately 2 ppbv (parts per billion by volume) despite low O₃ concentrations of approximately 10 ppbv, with the loss being up to 100 % greater than that without iodine. This finding suggests that warming SST driven by climate change might affect the marine atmospheric chemical balance through iodine–ozone chemistry.