57 Origin of the Seasonal Variation of Total Column Ozone in High Northern Latitudes

Monday, 17 June 2013
Bellevue Ballroom (The Hotel Viking)
John C. Gille, Univ. of Colorado and NCAR, Boulder, CO; and S. Karol, D. Kinnison, B. Nardi, and V. Yudin

The total column ozone at high northern latitudes has a well-documented seasonal variation, with high values toward the end of winter decreasing to a minimum value in early autumn. Data from the High Resolution Dynamics Limb Sounder (HIRDLS) have been used to study the descent of high-ozone air in the Brewer-Dobson circulation to create the winter maximum, and the subsequent isentropic mixing to lower latitudes leading to the decrease. These show that a large part of the total seasonal variation is due to the 330-450K levels in the UTLS. This is because a barrier to rapid mixing to low latitudes exists during the winter, causing a large build-up poleward of 40°N. In spring the barrier weakens and later disappears, allowing rapid mixing. Summing the HIRDLS observations of contributions by the different atmospheric layers gives excellent agreement with OMI total column measurements.
- Indicates paper has been withdrawn from meeting
- Indicates an Award Winner