OASIS3 is a climate model coupler, developed by CERFACS as part of ENES. It simplifies the exchange of data between components of a climate model: typically the atmosphere, ocean and chemistry models, which need to pass fluxes at boundaries. OASIS handles the interpolation of data between the different grids used in the different models, and ensures optimised data flow. At ICHEC, it is used in the EC-Earth climate model, for example, to connect the NEMO ocean model and IFS atmosphere model, passing information about water, heat and momentum fluxes, etc.
Several research groups in Ireland are currently using OASIS or planning on using it to implement coupled models. Hence ICHEC has undertaken work to optimise OASIS3 for EC-Earth, and we are now testing OASIS4.
OASIS4 is a new parallelized version of OASIS. To date, this has not been implemented in climate models. As part of a collaboration with NUI Maynooth, Dr. Adam Ralph is now testing OASIS4 by implementing it within the WRF (atmosphere) and ROMS (ocean) model, in particular working on ensuring that interpolation at coastlines, a problematic area in OASIS3, works correctly. This work is undertaken as part of the Silicon Graphics - ICHEC Centralised Application Support (CAS) group, and is co-funded by SGI.
ICHEC is pleased to have some NVIDIA Tesla GPGPU cards present in the Stoney computer. Based on Graphics processor technology, these have 240 cores each, enabling the highly-parallel execution of code written in CUDA or OpenCL.
As part of a collaboration with NUI Maynooth, Nicola McDonell is now working on implementing some of the physics kernels of WRF, used at NUIM, on the stoney computer with the Tesla cards. Previous work by at Michalakes et al. at NCAR with WRF on nVidia systems has shown a 100-fold speedup of the physics kernel of WRF, or a 30% speedup of the overall model.
In conjunction with the EC-Earth collaboration with Met Éireann and UCD, Dr. Shiyu Wang has started an EPA Fellowship at ICHEC on Ensemble prediction of extreme events. This will use the results from the EC-Earth model as well as other models run at UCD and Met Éireann to predict the freqency and severity of extreme events such as flooding over the next century in Ireland.
Work has started to parallelize the Numerical Wave Tank model of Prof. Frederic Dias , Visiting professor at UCD. Working with collaborators at UCC and abroad, this work should enable the better modelling of ocean waves and wave power generation in Ireland.