Numerical Modelling of the Extratropical Storm Delta Over Canary Islands: Importance of High Resolution - Selected Topics of Computational and Experimental Fluid Mechanics - page 141

Delta storm affected the Canary Islands. This was a result of interactions between
large-scale airflow (Delta storm) and the complex local topography of the islands.
The development and evolution of the Delta storm was a challenge for forecasters
and numerical weather predictionmodels (e.g., ECMWF, HIRLAM), which underes-
timated the speed and impact of the stormduring its evolution near the Canary Islands.
In this sense, high-resolutionmodelling clearly contributes to understand the physical
processes that lead to the observed strong wind speeds and gusts. The analysis of the
simulation results shows that most of the modifications of the model parameters had
a moderate to strong impact in the 10m maximum wind speed solution. The greatest
positive variations were associated with modifications of the Boundary-Layer and
Surface-Layer parameterization, and especially the increase in horizontal resolution.
The results clearly show the importance of working with high spatial horizontal
resolution and the need to use a nonhydrostatic mesoscale meteorological model to
simulate more correctly this type of meteorological phenomenon in domains with
complex or very complex topography.
Acknowledgments The authors wish to thank the AEMET (Spanish Met Office) and the ECMWF
for the IFS-ECMWF data and the surface meteorological observations. The simulation was per-
formed with the MareNostrum Supercomputer held by the Barcelona Supercomputing Center-
Centro Nacional de Supercomputación.
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