Breaking-up is hard to do
But ozone holes always get there in the end.
About a month ago I prematurely predicted the beginning of the end of this year’s ozone hole. Its finally happening. By early November the remaining area of low ozone was completely displaced from the south pole towards Africa, as shown below (from here). Ozone amounts over New Zealand were still fine.
A week or so beforehand, we witnessed rather nice sequence of events as it started to break up. I put a quick message out on substack notes, but I’m not sure how many saw it.
The graphic below is copied form NASA’s Ozone-Watch web site. The large image at left is the ozone map for 30 October, where the blue regions indicate low ozone amounts characteristic of ozone-hole conditions (ozone less than 220 DU, as shown in the colour scale at bottom). At the lower right of this large image, you can see a region of low ozone amounts extending out from the Antarctic continent over the Southern Ocean.
The smaller images at right show the development of this over the previous four days, as tongues of ozone-poor air detach from the main ozone hole.
As usual, all the action was safely away from the Australasian sector. The largest mid-latitude ozone depletion were to the East of Africa.
If you look closely at these images, you sometimes see discontinuities at longitudes near the international date line. That’s at the lower left of these plots, just to the east of New Zealand (where ozone amounts were still relatively high). The discontinuities arise because the image is built up from a sequence of satellite overpasses. It takes less than 2 hours for a complete satellite orbit of the globe but each overpass samples only a small range of longitudes, so it takes it takes about a day to build up a complete picture. Any changes in underlying ozone over that period will appear as discontinuities at the end points of the integration time, which occur at the dateline.
The discontinuity is more obvious in the image from 29 October, shown below.
Overall, this year’s ozone hole was the 7th smallest since recovery began in the late 1990s, as shown below (also from here).
Take a look here to see the current situation.
