5 Shown here is the chemical ozone loss in northern winter as well its
6 effects on mid latitudes in Europe. For example, in winter 2010/2011
7 there was a very high ozone depletion in the area of the Arctic polar
8 vortex. In the frame of the `Knowledge Platform "Earth and Environment" (ESKP)`_
9 the effects this ozone loss at mid latitudes are explained and
10 documented on a daily basis. An early warning system for such events
11 is thus established. The basis is simulations with the Jülich
12 chemical transport model `CLaMS`_, which uses innovative transport and
13 mixing algorithms to calculation of the exchange of air masses between
14 polar and mid Latitudes (e.g. interference of low-ozone air in
15 Europe). The realistic simulations are initialized by satellite
16 observations and driven by ECMWF meteorological analyzes.
18 The ozone depletion in the polar vortex is determined by the
19 temperature. For polar ozone loss, the temperature must drop below a
20 threshold of approximately -78°C. For the Arctic winters of 2010-2020
21 the `Calculations of ozone loss`_ and `Estimates from temperature`_
22 are shown. To explain and assess the results, it is also explained
23 how the `UV increase`_ on the ground develops in the course of spring
24 for the case of different ozone losses. Calculated ozone loss and
25 ozone column as well as the calculated from it maximum UV index (at
26 noon with a clear sky) are considered `Map display`_ shown for the
29 Typically, the ozone columns in the Arctic are still higher than in
30 the Antarctic despite ozone depletion, so that in the Arctic spring
31 there is so far at most a moderate UV radiation at the ground.
36 The calculations **for the current winter 2019/2020** show so far
37 somewhat above average ozone depletion. Towards the end of January
38 the stratospheric Temperatures are very low, i.e. high ozone depletion
39 could follow if the polar vortex remains stable.
45 Last winter 2018/2019 the stratospheric temperatures were too high for
46 significant chlorine-catalyzed ozone depletion. A so-called "major
47 warming" in early January led to the warming the stratosphere to split
48 off a part of the polar vortex.
50 In recent years, Winter 2010/2011 and 2015/2016 were particularly
51 noteworthy, as they were characterized by a cold, stable polar vortex,
52 which with clear corresponding ozone depletion. This yielded only a
53 slight increase in UV radiation, which is typically low in our
54 latitudes in March. Extremely high UV values like in the Antarctic
55 spring under the ozone hole did not occur so far in the Arctic.
60 The stratospheric temperatures in winter 2015/2016 were as low as
61 never seen in recent decades before with the result of a very high
62 ozone loss of over 100 DU. The lower ozone columns resulted in a
63 slight increase in UV radiation on the ground. However, the UV
64 radiation is in these latitudes is low at this time of year. When
65 these air masses of the polar vortex moved towards mid-latitudes, the
66 UV index in early March is as high as normally expected in late
67 March. Extremely high UV values as in the Antarctic spring under the
68 ozone hole did not yet occur in the Arctic.
73 The images below show the geographical distribution of the calculated
74 ozone column (top) and ozone loss (bottom) for March 28, 2011. Shown
75 is the total column between 12 and 22 km altitude in Dobson Units (DU).
77 .. _Calculations of ozone loss: /ozoneloss/clams/2020
78 .. _Estimates from temperature: /ozoneloss/vpsc/2020
79 .. _UV increase: /ozoneloss/uvi
80 .. _Map display: /ozoneloss/uvmap/200119
81 .. _Knowledge Platform "Earth and Environment" (ESKP): /eskp
82 .. _CLaMS: http://en.wikipedia.org/wiki/CLaMS