102
(Table 3.7.2.1) and also the PETmin for the levels of > 18. It can be seen that there
is a difference in the conditions for maxima over Ta > 30 and only 1 or 2 days for
Ta > 35 °C. In addition, it can be seen that Tamin conditions over > 18 and > 20 occur
mostly in the urban area. Maximum values of PET are represented by a similar
picture; however, the PET is generally higher than air temperature, while extreme
heat stress (PET > 41 °C) can occur in more than 20 days per year in the city stations. The daily minimum value of PET never exceeds the threshold of 18 °C in
Stuttgart (the frequency is below 0.1 %).
Fig. 4.3 Bean plots for air temperature (upper graphs), PET (middle graphs) and UTCI (lower
graphs) for the Stations Echterdingen (E), Schnarrenberg (Sb), Neckartal (N), Schwabenzentrum
(S) and Hohenheim (H) for the period 2000–2011
Table 4.4 Number of days on which defined thresholds are exceeded
Echterdingen Schnarrenberg Neckartal Schwabenzentrum
Hohenheim
T amax > 30
8
13
10
14
7
T amax > 35
1
2
1
2
1
T amin > 18
3
15
11
20
6
T amin > 20
0
4
2
6
1
PET max > 30
93
85
96
99
92
PET max > 35
55
57
58
61
54
PET max > 41
16
26
19
23
15
PETmin > 18
0
0
0
0
0
A. Matzarakis et al.