Comment on 13: I fully agree with Markus Rex that total ozone
measurements can not give any clues on chemical destruction
in isolated
layers, and that we may have been lucky that O3 transport cancelled out the chemical
thinning that happened during the last months.
The 1999 event was still visible
in CTD profiles [a sequence of
measurements of water conductivity, temperature, depth]
in 2007 along the Gakkel Ridge as a
thin layer (50 - 200 m thick) with slightly warmer temperatures (~ 0.01 — 0.001 C warmer).