About GALES
Clouds & Climate is a group within the Faculty of Applied Sciences at the Delft University of Technology. As a group, we perform fundamental research in the turbulent processes involved in cloud dynamics. The resulting knowledge may be applied to weather or climate models, improving their forecasts. We often employ (high-resolution) simulations to simulate the behavior of clouds in different climate conditions. At this moment, how clouds respond to climate change is one of the key uncertainties in climate modeling.
GALES: GPU-resident Atmospheric Large-Eddy Simulation
In order to study cloud procesesses in detail, often Large-Eddy Simulations (LES) are employed. These simulations model the finest turbulence scales, but explicitly resolve (aka calculate) the larger turbulence motions, allowing one to study the turbulent motions responsible for producing the low clouds which have so much impact on the daily weather. These simulations are computationally so heavy, however, that they're typically performed using supercomputers or clusters, using dozens of processors in p
arallel.
In combination with the Delft Computer Graphics Group, our FORTRAN90-based parallel Dutch Atmospheric LES (DALES) was rewritten in C++ and CUDA to be performed on the graphical processing unit (GPU). Using the large computational power ofmodern-day GPUs, simulations which otherwise would require dozens (32-64) processors can now be run on a desktop PC with equivalent speeds. Also, the GPU is able to directly render the three-dimensional dynamics of the atmosphere by 'volume rendering' the cloud field or show particle releases, 2D cross-sections and live statistics.
GALES at Supercomputing 2011 @ Seattle
GALES will be present at the SC|11 event! This is one of the most important supercomputing&HPC events, and will this year be held in Seattle, WA, November 13-18th. GALES will be featured in the Holland Pavilion, with a poster and live demo's of the application.
GALES described in BAMS
An article about GALES is accepted for publication in the Bulletin of the American Meteorological Society. The article touches upon the subject of porting a simulation to CUDA, but more extensively discusses the advantages and disadvantages as well as the possibilities of atmospheric simulations on the GPU using CUDA.
The article is currently being processed and will soon be published under the title:
J. Schalkwijk; Griffith, E.; Post, F; and Jonker, H.J.J.; High performance simulations of turbulent clouds on a desktop PC: exploiting the GPU, Bulletin of the American Meteorological Society, 2012 (in press)
For a more thorough discussion of the physics and numerics of the model, note that GALES is 'under the hood' equivalent to the FORTRAN90-version of our Atmospheric LES, DALES. This model is described in:
T. Heus; van Heerwaarden, C. C.; Jonker, H. J. J.; Pier Siebesma, A.; Axelsen, S.; van den Dries, K.; Geoffroy, O.; Moene, A. F.; Pino, D.; de Roode, S. R. & Vilà-Guerau de Arellano, J. Formulation of the Dutch Atmospheric Large-Eddy Simulation (DALES) and overview of its applications Geoscientific Model Development, 2010, 3, 415-444
Simulating with GALES
Just a small movie demonstrating a simulation of deep convective clouds using GALES, and showing some of the possibilities the user has to investigate the simulation.
More GALES movies
Some more nice movies of GALES simulations, showing:
a) Some typical midlatitude clouds, in a situation of moderate wind shear.
b) A similar case, but now the complex turbulent dynamics are illustrated somewhat by the continuous release of a passive smoke source (e.g. a burning building).