DOI: 10.5281/zenodo.16836163
title: Simulation of the downburst-producing thunderstorm that hit Genoa (Italy) on August 14, 2018: 3D wind fields

description: This dataset contains the wind fields of a downburst event simulated using CM1 (Cloud Model 1; https://www2.mmm.ucar.edu/people/bryan/cm1/; see Bryan and Fritsch, 2002) by Hourngir and Burlando (2025). The simulated downburst event occurred in the city of Genoa, Italy, on August 14, 2018, and is described in Burlando et al. (2020).

The three-dimensional wind fields are made available for the simulation time from 08:40 to 09:40 UTC, with time step equal to 5 min from 08:40 to 09:10 UTC and equal to 30 s from 09:10 to 09:40 UTC. They are extracted in the computational volume from -10.8544 km to 10.8544 km both in the X (W-E) and Y (S-N) direction, and from the ground level (i.e., the orography) to 15 km ASL (above sea level) in the vertical direction. The origin (0,0) of the XY reference system corresponds to the position (484381.12 m E, 4925763,29 m N) in the 32T Universal Transverse Mercator geographical system (datum WGS84). For each wind field, the three components (u,v,w) are reported, where u is the zonal component (West-to-East, positive eastward), v is the meridional component (South-to-North, positive northward), and w is the vertical component (positive upward). The maximum horizontal resolution is 50 m at the origin and stretches outward with a constant stretching factor equal to 1.012. The vertical resolution is equal to 25 m from the ground (over the open sea, lower over the land) up to 500 m in altitude, and 200 m from 2.3 km to the top of the simulation domain. Each wind field file is an ASCII text file (.txt) with 6 columns: columns 1-3 are the X and Y coordinates (in km) and the Z coordinate (in m ASL); columns 4-6 are the (u,v,w) velocity components (in m/s). The file name convention is “wind_tHHMMSS.txt”, where HHMMSS is the UTC time in hours, minutes, and seconds.

The orography is also available as a constant bi-dimensional field defined in the same computational volume. The orography file is an ASCII text file (orography.txt) with 3 columns, representing X and Y coordinates (in km) and altitude (in m ASL).

Wind fields and orography are available for both the simulations described in Hourngir and Burlando (2025), which differ for the adopted sub-grid turbulence scheme (Deardorff 1980, and Smagorinsky 1963). Accordingly, two separate zip archives are provided, named TKE.zip and Smag.zip, respectively. In addition, two Matlab scripts (orography.m and wind.m) are also provided to convert the .txt files into .vtk format, which can be loaded for visualization using (for example) Paraview.

 

References

Bryan G. H. and J. M. Fritsch (2002). A benchmark simulation for moist nonhydrostatic numerical models. Monthly Weather Review, 130(12):2917–2928

Burlando M., D. Romanic, G. Boni, M. Lagasio and A. Parodi (2020). Investigation of the Weather Conditions During the Collapse of the Morandi Bridge in Genoa on 14 August 2018 using Field Observations and WRF Model. Atmosphere 11, 724. DOI: 10.3390/atmos11070724 – ISSN 2073-4433

Hourngir D. and M. Burlando (2025). Full-cloud numerical simulation of a translating isolated thunderstorm producing a wet downburst. J. of Wind Eng. and Ind. Aerodyn. (submitted)

Deardorff J. W. (1980). Stratocumulus-capped mixed layer derived from a three-dimensional model. Bound.-Layer Meteor. 18, 495–527

Smagorinsky J. (1963).  General circulation experiments with the primitive equations. I. The basic experiment. Mon. Wea. Rev. 91, 99–164