Erdfernerkundung - Numerische Physik: Modellierung

5.5. CAWSES 271
Abbildung 5.38: Ozone depletion following the series of large events in October/November
2003: modeled and observed ozone variations in the northern and southern hemisphere [205]
§ 902 In addition, the largest events provide the best test case for modeling: if the effect is
large, its dilution due to natural variability is small. Thus a large solar particle event provides
some kind of δ-stimulus for the atmosphere and its response can be analyzed despite all the
natural noise underlying it. And solar energetic particle events can become quite large: in the
Bastille day event in Fig. 5.30, particle intensities increase by up to 6 orders of magnitude
above background thus providing a strong stimulus.
§ 903 As a consequence, large solar energetic particle events can be used to calibrate the
model chain mentioned above before we attempt to derive more subtle effects from our
models.
§ 904 To demonstrate the validity of the model chain, Fig. 5.38 shows comparisons between
measurements by SCIAMACHY (top and third panel) and modeled (second and fourth panel)
depletions in ozone following the large events in October/November 2003 for the northern
(top panels) and southern (bottom panels) hemisphere. Spatial and temporal patterns in both
hemispheres are reproduced quire reasonably, although as discussed before ozone depletion
in the mesosphere is overrated while it is underestimated for late times in the stratosphere.
However, these deviations between observations and model are small compared to the asymmetry
between the two hemispheres: while both model and observations indicate a strong
ozone depletion in the northern hemisphere, ozone variations in the southern hemisphere are
almost negligible. Reasons for this asymmetry will be discussed below.
Long–Term Effects of Solar Energetic Particle Events
§ 905 While the modeling of the influence of individual particle events on ozone is a goal
in itself, our interest is concerned more with longer times scales, in particular time scales
c○ M.-B. Kallenrode 2. Juli 2008