20
and the urban canyons form obstacles against low sun-rays. In December and
January UHI feature can be seen all day, however the maximum intensities are
lower than in summer.
1.3.3.4 Summary
At HMS SURFEX dynamical scheme is applied to describe interactions between
the atmosphere and the urban surfaces. Some 10-year long test simulations were
accomplished with the model over Budapest and Szeged. In this paper preliminary
results of these validation experiments are performed. Based on the results, SURFEX
captures the main characteristics of the urban climatology: temperature excess in
Fig. 1.9 Monthly mean
temperature bias (°C) of
ALADIN-Climate (filled
squares) and SURFEX
(open squares) compared
to observations in the inner
(solid lines) and outer site
(dashed lines) of Szeged
for 1999–2000
Fig. 1.10 Annual and daily cycle of UHI intensity (°C) in 1991–2000 between the two selected
points in Szeged simulated by SURFEX
J. Fallmann et al.