Numerical Modelling of the Extratropical Storm Delta Over Canary Islands: Importance of High Resolution - Selected Topics of Computational and Experimental Fluid Mechanics - page 139

Fig. 5 10mwind speed comparison of model results versus meteorological observations. Location
of surface stations is depicted in the bottom-left panel of Fig. 3 ( Black line 15min mean surface
measurements; blue circle 9km domain; green triangle 3km domain; red square 1km domain)
model results. The model results show a regular increase of the wind speed at 10m
from 18 to 108km/h in La Palma-E145 station for the period of study. The Santa
Cruz de Tenerife-E044 station shows a sudden increase in the wind field, suggesting
the presence of mountain wave activity aloft those impacts at surface levels with the
development of a downslope wind event (as it has been shownwith themodel results).
The results show how in the Santa Cruz de Tenerife-E044 station the high-resolution
simulations (3 and 1km) reproduce the sudden increase in wind speed reasonably
well, improving the 9km simulation. But it is also where the simulation results show
the largest deviations. This is due to the topographic component of the location of
the station, at the sea level, and conditioned by the situation bay surrounded by
mountains with an important altitude difference.
The use of modelling allows another important and significant finding. We eval-
uated that the effect of this storm is enhanced due to the existence of a complex
topography with high altitudes (the Teide volcano has a height of 3,718 m). Figure 6
shows the results of the different patterns for the three spatial resolutions with and
without topography. The dynamic pattern is totally different; and it highlights the need
to work at high spatial resolutions. This is especially evident on the Tenerife Island.