Thanks Richard, recordings for 2020 plotted in the graph on NIWA’s webpage “UV and ozone” show slightly reduced Ozone levels from July to August but not from January to June. Where can I see a graph which plots and trends mean annual Ozone concentrations for the past 10 years including 2020 to indicate how much Ozone recovery has taken place?
Ozone reduction, and therefore recoveries are small outside Antarctica, as shown in our recent paper (and data supplement), "Success of Montreal Protocol Demonstrated by Comparing High-Quality UV Measurements with 'World Avoided' Calculations from Two Chemistry-Climate Models”. See https://www.nature.com/articles/s41598-019-48625-z
Richard, You wrote: “recoveries are small” For the past 10 years we read that ozone concentrations were slowly increasing. But comparing ozone concentrations for the current year (2020) with the average and range for all other years is unconvincing because ozone concentrations vary too much from year to year. UV Measurements also show very little change from year to year which indicates very little increase in ozone concentrations. Perhaps I am missing something.
What is the rate of increase in ozone concentration as measure at Lauder from 2010 until 2015? What is the rate of increase in ozone concentration as measure at Lauder from 2016 until 2020? Those numbers will be convincing.
The answers to your questions can be gleaned by a careful reading of the paper (and supplement to it) that I linked in my previous reply. Like I said, due to the huge success of the Montreal Protocol, ozone changes have been small at mid latitudes (meaning any changes are only slightly larger than the natural year to year variability). If you don't want to pore over the plots in my paper, you can download the satellite data and plot them for yourself. Or I can do it for a fee.
Richard, Can you also show the history of levels of Ozone depletion for the first half of the year?
Tables of ozone amounts for Antarctica can be found at https://ozonewatch.gsfc.nasa.gov/
A plot of ozone for Lauder is shown at https://niwa.co.nz/our-services/online-services/uv-ozone (interestingly, there were low values earlier in the year – which may be related to Australian bush-fires)
Thanks Richard, recordings for 2020 plotted in the graph on NIWA’s webpage “UV and ozone” show slightly reduced Ozone levels from July to August but not from January to June. Where can I see a graph which plots and trends mean annual Ozone concentrations for the past 10 years including 2020 to indicate how much Ozone recovery has taken place?
Ozone reduction, and therefore recoveries are small outside Antarctica, as shown in our recent paper (and data supplement), "Success of Montreal Protocol Demonstrated by Comparing High-Quality UV Measurements with 'World Avoided' Calculations from Two Chemistry-Climate Models”. See https://www.nature.com/articles/s41598-019-48625-z
The NIWA plot compares ozone at Lauder for the current year (2020) with the average and range for all other years (blue line and grey areas). See https://niwa.co.nz/our-services/online-services/uv-ozone
Richard, You wrote: “recoveries are small” For the past 10 years we read that ozone concentrations were slowly increasing. But comparing ozone concentrations for the current year (2020) with the average and range for all other years is unconvincing because ozone concentrations vary too much from year to year. UV Measurements also show very little change from year to year which indicates very little increase in ozone concentrations. Perhaps I am missing something.
What is the rate of increase in ozone concentration as measure at Lauder from 2010 until 2015? What is the rate of increase in ozone concentration as measure at Lauder from 2016 until 2020? Those numbers will be convincing.
The answers to your questions can be gleaned by a careful reading of the paper (and supplement to it) that I linked in my previous reply. Like I said, due to the huge success of the Montreal Protocol, ozone changes have been small at mid latitudes (meaning any changes are only slightly larger than the natural year to year variability). If you don't want to pore over the plots in my paper, you can download the satellite data and plot them for yourself. Or I can do it for a fee.
Because of the large year-to-year variability in ozone, trends over periods less than ten years are meaningless.