EGU2020-21998, updated on 12 Jan 2022
EGU General Assembly 2020
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Quantitative Detection of Iodine in the Stratosphere

Rainer Volkamer1, Theodore Koenig1, Pedro Campuzano-Jost1, Alfonso Saiz-Lopez2, Jose Jimenez1, Rafael Fernandez3, Doug Kinnison4, and Carlos Cuevas2
Rainer Volkamer et al.
  • 1University of Colorado at Boulder, Department of Chemistry & CIRES, Boulder, Colorado, United States of America (
  • 2Department of Atmospheric Chemistry and Climate, Institute of Physical Chemistry Rocasolano, Spanish National Research Council, 28006 Madrid, Spain
  • 3National Research Council (CONICET), Mendoza 5501, Argentina
  • 4Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder, CO 80301

Ozone in the extrapolar lower stratosphere is currently declining for reasons that are not well understood. Iodine is emitted mostly from marine sources, and changing iodine emissions provide a possible chemical reason for why ozone in the lower stratosphere continues to decline (Koenig et al., 2020). Previous stratospheric measurements had detected iodine qualitatively in particles. More recently, IO observations in the daytime tropical tropopause layer (TTL) have suggested that between 0.25 to 0.70 pptv Iy are injected into the stratosphere, which is 1.6 to 3.5 times the WMO2014 upper limit. These indirect observations have led to revised estimates of 0 - 0.8 pptv Iy stratospheric injection in the WMO2018 report. This presentation discusses first quantitative measurements of IO radicals and of submicron particulate iodine from aircraft in the stratosphere that support 0.77 pptv Iy stratospheric injection. Our observations support the WMO2018 upper limit estimate, and clearly are incompatible with zero iodine injection. The implications of the obseved iodine concentrations for ozone loss in the lower stratosphere are discussed, also in light of climate records that find increasing iodine in recent decades, observed ozone trends, and ongoing and future research needs to better quantify iodine's contribution to explain these trends. 

How to cite: Volkamer, R., Koenig, T., Campuzano-Jost, P., Saiz-Lopez, A., Jimenez, J., Fernandez, R., Kinnison, D., and Cuevas, C.: Quantitative Detection of Iodine in the Stratosphere, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-21998,, 2020.