Irish Meteorological Society, March 20
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Posted on 7 April 2014
ICHEC was invited to speak at the Irish Met Society’s series of public talks on March 20th, 2014. The event was held at the Custom House, Dublin. Dr. Paul Nolan, climate scientist at ICHEC, presented an overview of the research carried at ICHEC to forecast the weather and predict the future climate of Ireland.
ICHEC and Met Éireann are involved in a collaboration to develop and run both Climate and Numerical Weather Prediction models. As part of this collaboration, ICHEC provides the computational facilities and support to Met Éireann to enable it to run its operational forecast models on ICHEC’s recently installed supercomputer, Fionn.
The talk provided an overview of running weather forecast and climate models on the ICHEC supercomputers.
Results were presented showing climate change projections for Ireland. A large ensemble of high-resolution climate simulations for Ireland was run on the ICHEC supercomputers. Mid-century climate change projections were presented for an ensemble of medium and high greenhouse gas emission scenarios.
Key climate change results for mid-century were presented:
Figure1. Projected mid-century temperature changes for the high emission ensemble; (left) the top 5% of summer highest daytime temperatures and (right) the lowest 5% of winter night-time temperatures.
Figure 2. Projected change (%) in the frequency of very wet days (>20mm of precipitation) for winter for (left) medium-low emissions and (right) high emissions. Changes for mid-century (2041-2060) are shown relative to the past (1981-2000).
Results were also presented on research carried out by climate scientists at ICHEC to improve the accuracy of the Met Éireann forecasting model, HARMONIE. This is currently run at a horizontal resolution of 2.5km. Scientists at ICHEC have worked to increase this resolution to 500m, thus providing more accurate forecasts. An example of such research is presented in Figure 3 below. Here, the 24-hour forecasted wind flow over the region of Killary harbor in the West of Ireland is shown. The left panel shows the forecasted wind flow of the operational Met Éireann model. The right panel shows the improved high-resolution model. The flow-field as forecast by the 2.5km Harmonie looks relatively undifferentiated and insensitive to the underlying topography. Meanwhile, the 0.5km Harmonie runs show wind-fields that are clearly steered by the mountains and funneled through the valleys in a way that is more realistic.
Figure 3. Close-up of region around Killary Harbour showing the model topography and surface wind fields from a 24-hr forecast by two different Harmonie runs. (left) Met Éireann 2.5km resolution Harmonie. (right) ICHEC 0.5km resolution Harmonie with hi-res Aster topography.
Finally, an overview was given on research carried out at ICHEC to speedup execution time of the Met Éireann forecasting models by applying state-of-the art HPC techniques and accelerators such as GPUs and the Intel Xeon Phi coprocessor.
After the talk, Paul presented a 3D visualization of global climate change.
The animation below presents an ICHEC visualization of Met Éireann EC-EARTH data. The annual 2m temperature change with respect to the 30-year baseline (1961-1990) is presented for both the RCP4.5 (medium) and RCP8.5 (high) scenarios.
The second visualization presents the Annual Sea Surface Temperature (SST) and Sea Ice Fraction for March and September. Because of the high heat capacity of water, the SST lags behind atmospheric temperatures. Hence, the artic has sea ice extend is at a maximum during March and minimum during September.