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.
34 **The current winter of 2023/2024** shows low stratospheric
35 temperatures in December and another period with medium to low
36 temperatures at the end of February/beginning of March. Thus there was
37 moderate ozone depletion, calculated to be around 70 DU.
43 In recent years, the winters 2010/2011, 2015/2016, and 2019/2020 were particularly
44 noteworthy, as they were characterized by a cold, stable polar vortex,
45 which with clear corresponding ozone depletion. This yielded only a
46 slight increase in UV radiation, which is typically low in our
47 latitudes in March. Extremely high UV values like in the Antarctic
48 spring under the ozone hole did not occur so far in the Arctic.
54 The stratospheric temperatures in the winter of 2019/2020 were again
55 very low and the polar vortex was stable for a very long time. Both factors
56 led to the largest Arctic ozone loss to date. In the meantime
57 this is extensively documented in the scientific literature (`1`_, `2`_).
62 The stratospheric temperatures in winter 2015/2016 were as low as
63 never seen in recent decades before with the result of a very high
64 ozone loss of over 100 DU. The lower ozone columns resulted in a
65 slight increase in UV radiation on the ground. However, the UV
66 radiation is in these latitudes is low at this time of year. When
67 these air masses of the polar vortex moved towards mid-latitudes, the
68 UV index in early March is as high as normally expected in late
69 March. Extremely high UV values as in the Antarctic spring under the
70 ozone hole did not yet occur in the Arctic.
75 The images below show the geographical distribution of the calculated
76 ozone column (top) and ozone loss (bottom) for March 28, 2011. Shown
77 is the total column between 12 and 22 km altitude in Dobson Units (DU).
79 .. _Calculations of ozone loss: /ozoneloss/clams/2020
80 .. _Estimates from temperature: /ozoneloss/vpsc/2020
81 .. _UV increase: /ozoneloss/uvi
82 .. _Map display: /ozoneloss/uvmap/200119
83 .. _Knowledge Platform "Earth and Environment" (ESKP): /eskp
84 .. _CLaMS: http://en.wikipedia.org/wiki/CLaMS