Large Eddy Simulations for an Urban Canopy and Vegetated Canopies on Complex Terrain

Vegetated Canopy on Complex Terrain: (collected by Benjamin Udina)

The data here stored is from simulations of a dense vegetated canopy on varying degrees of surface complexity. The data is used to investigate the properties of the atmospheric roughness sublayer as it pertains to momentum statistics, turbulent kinetic energy (TKE) budget, and turbulence anisotropy. The dense vegetated canopy has the structural and aerodynamic characteristics of the Amazon rainforest; the canopy height is hc = 39 m, and the vegetation is characterized by a vertically distributed leaf area density, with a Leaf Area Index (LAI) of 7.05. The underlying topography presents three levels of complexity: flat, sinusoidal hills, and a realistic case meant to reproduce the topographic region around the ATTO tower in the Amazon forest. The simulations were run for neutral stratification. The domain size is Lx=Ly=2880 m and Lz=960 m. The numerical grid discretization is Nx=Ny=256 and Nz=384. The data is non-dimensionalized using a length scale zi=1000 m and a velocity scale u=0.4 m/s. The flow is forced using a geostrophic wind speed of 4 m/s. The topography is implemented using an immersed boundary method (IBM); as such, the first 5 grid points closest to the surface are used for the definition of the IBM surface and are thus excluded from the data, so that the 3D shape of the data fields is (256,256,379). 

The .zip folders named "phi_functions_xxxxx.zip" contain the files that are needed to plot the topography. The folders need to be downloaded and extracted before use. The netCDF files "data_xxxx.nc" contain the 3D fields needed for the computation of momentum statistics, TKE budget terms, and turbulence anisotropy.

A python script, 'load_data.py', is included with a few simple commands to import the data and surface files.

Urban Canopy: (collected by Marco Giometto)

This dataset, 'profiles.mat', contains profiles from LES of flow over the Giometto et al. (2016) subset of the city of Basel, Switzerland. Profiles with a `_xy` have been obtained via averaging in time and over the horizontal directions. Profiles with a `_tw` correspond to time-averaged quantities sampled at the location of a meteorological stations in the Sperrstrasse street. 

The profiles here provided correspond to the simulation ID G, see the referenced publication for details.

A script is provided for loading the `.mat` files in Python, 'import_and_plot.py'.

References:
Giometto M.G., Christen A., Meneveau C., Fang J., Krafczyk M., and Parlange M.B. (2016) Spatial characteristics of roughness sublayer mean flow and turbulence over a realistic urban surface. In Bound.-Layer Meteorol., 160, 425–452. https://doi.org/10.1007/s10546-016-0157-6