• P. 157, L. 3070: Has the Antarctic polar vortex really persisted into late December?

  • P. 157, L. 3079-3086: In the context of summertime UV changes, it is pertinent that summertime high-latitude ozone trends are attributable to springtime losses over the entire extratropics (and hence to ODSs). See Figure 3-18 of the WMO report (2007).

  • P. 157, L. 3084-3086: These low-ozone episodes are not ODS-related.

  • P. 157, L. 3086: List these references.

  • P. 158, Figure 3.17: The figure caption and the ordinate axis label should agree. Perhaps no data are available for a northern hemisphere site closer to the latitude of Palmer, which would make a nicer comparison. There is a 50% difference in summer UV between Barrow and Palmer that is more than just a reflection of the latitude difference. Also, include a reference for the data or for the plot.

  • P. 159, L. 3102: At beginning of this section, elaborate (briefly) on the lost next-to-last “key finding” about “acute health effects of UV-B exposure.” They are nowhere discussed or even listed, and they should at least be enumerated with adequate reference to other sources. The authoring team could look at (Lloyd 1993); this short review article also has many of the standard references (which should be updated). The authoring team may also refer to the WMO’s 20 questions document (Fahey 2007), specifically the question on skin cancer. Keep in mind that the differences between the hemispheres are not solely clouds, but also the larger column ozone in the NH, aerosol differences (more in NH), etc.

  • P. 159, Figure 3.18: Change the color bar to indicate two sets of units: kW/m2sec and the maximum UV index at each location in each month. The latter is more familiar to the average reader. .

  • P. 161, L. 3142: If this really is the bottom line, the authoring team should contrast what is currently observed as far as UV-B changes (not much) versus what would have happened, had the Montreal Protocol not been implemented.

  • P. 161, L. 3148: Why? If EESC is still rising in 1993, it must be temperatures, dynamics, etc.

  • P. 161, L. 3153: Replace “7%” to “8%” to be consistent with P. 160.

  • P. 165, L. 3316: Complete this reference.


The purpose of Chapter 4 of the draft SAP is to examine the relationships between human impacts on ozone and the changes occurring in the climate system. Overall, the chapter does a good job of capturing the main issues, but the presentation of these issues should be improved. In particular, as discussed in the overarching comments of this peer review report, there needs to be a better framing of the two-way interaction between ozone and climate. Several major and specific comments are made below.

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