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.
38 Since the end of January the statospheric
39 temperatures are very low and the polar vortex remains stable. End of February
40 the average column ozone loss reached about 70 DU, the second highest value
41 in the last decade after 2016.
42 On 10 March the calculated average ozone loss was 95 DU, which
43 corresponds to the maximum value for 2011, that was however only
44 reached in late March. On 14 March, the value of 110 DU was exceeded
45 **thus the ozone loss this year is the highest of the years considered here**.
50 Last winter 2018/2019 the stratospheric temperatures were too high for
51 significant chlorine-catalyzed ozone depletion. A so-called "major
52 warming" in early January led to the warming the stratosphere to split
53 off a part of the polar vortex.
55 In recent years, Winter 2010/2011 and 2015/2016 were particularly
56 noteworthy, as they were characterized by a cold, stable polar vortex,
57 which with clear corresponding ozone depletion. This yielded only a
58 slight increase in UV radiation, which is typically low in our
59 latitudes in March. Extremely high UV values like in the Antarctic
60 spring under the ozone hole did not occur so far in the Arctic.
65 The stratospheric temperatures in winter 2015/2016 were as low as
66 never seen in recent decades before with the result of a very high
67 ozone loss of over 100 DU. The lower ozone columns resulted in a
68 slight increase in UV radiation on the ground. However, the UV
69 radiation is in these latitudes is low at this time of year. When
70 these air masses of the polar vortex moved towards mid-latitudes, the
71 UV index in early March is as high as normally expected in late
72 March. Extremely high UV values as in the Antarctic spring under the
73 ozone hole did not yet occur in the Arctic.
78 The images below show the geographical distribution of the calculated
79 ozone column (top) and ozone loss (bottom) for March 28, 2011. Shown
80 is the total column between 12 and 22 km altitude in Dobson Units (DU).
82 .. _Calculations of ozone loss: /ozoneloss/clams/2020
83 .. _Estimates from temperature: /ozoneloss/vpsc/2020
84 .. _UV increase: /ozoneloss/uvi
85 .. _Map display: /ozoneloss/uvmap/200119
86 .. _Knowledge Platform "Earth and Environment" (ESKP): /eskp
87 .. _CLaMS: http://en.wikipedia.org/wiki/CLaMS