资源环境科技发展态势分析平台

We investigate the role of the tropics, the stratosphere, and atmosphere-ocean coupling for seasonal forecasts of strong, potentially damaging, Northern Hemisphere extratropical winter wind storm frequencies. This is done by means of relaxation experiments with the European Centre for Medium-Range Weather Forecasts model, which allow us to prescribe perfect forecasts for specific parts of the coupled atmosphere-ocean system. We find that perfect predictions of the Northern Hemisphere stratosphere significantly enhance winter storm predictive skill between eastern Greenland and Northern Europe. Correct seasonal predictions of the occurrence of stratospheric sudden warmings play a decisive role. The importance of correctly predicting the tropics and of two-way atmosphere-ocean coupling, both for forecasting stratospheric sudden warming risk and, correspondingly, severe winter storm frequency, is noted.

Plain Language Summary Wind storms rank among the most expensive types of natural hazards in the Northern Hemisphere (NH) during winter and can yield severe damage and heavy loss in both Europe and North America. Therefore, predictions of these events well in advance are of large interest to a number of societal, economic, and scientific sectors. We investigate the factors that potentially influence winter storm frequency, namely, sea surface temperature anomalies in the tropics, and conditions in the NH stratosphere. We find that correct seasonal predictions of the NH stratosphere significantly improve winter storm seasonal predictions between eastern Greenland and Northern Europe. Correct seasonal predictions of the occurrence of extreme events in the stratosphere, so-called stratospheric sudden warmings, play a decisive role. We further note the importance of correctly predicting the tropics and of two-way atmosphere-ocean coupling, both for forecasting stratospheric sudden warming risk and, correspondingly, severe winter storm frequency.