New Publication Large amounts of iodine in upper troposphere

Karolin Voss and co-workers have found unexpectedly large abundances of up to 0.6 ppt iodine oxide (IO) in the upper troposphere. They used DOAS measurement onboard the HALO research aircraft flying over the North Atlantic in late summer 2017 during the WISE campaign. It turns out that the large abundance of IO are related to air masses that have been processed by hurricanes more than 10 days prior to the measurements. This provides compelling evidence that hurricanes can provide fast upward transport and, potentially due to enhanced wind-speeds, increased emissions of iodine source gases at the surface. Further research is required to disentangle these processes and to budget the role of hurricanes and deep convection events for the global iodine background in the middle atmosphere.