This paper examines an asymmetric spatiotemporal connection and climatic impact between the winter atmospheric blocking activity in the Euro-Atlantic sector and the life cycle of the North Atlantic Oscillation（NAO） ...This paper examines an asymmetric spatiotemporal connection and climatic impact between the winter atmospheric blocking activity in the Euro-Atlantic sector and the life cycle of the North Atlantic Oscillation（NAO） during the period 1950–2012. Results show that, for positive NAO（NAO＋） events, the instantaneous blocking（IB） frequency exhibits an enhancement along the southwest–northeast（SW–NE） direction from the eastern Atlantic to northeastern Europe（SW–NE pattern, hereafter）, which is particularly evident during the NAO＋decaying stage. By contrast, for negative NAO（NAO-）events, the IB frequency exhibits a spatially asymmetric southeast–northwest（SE–NW） distribution from central Europe to the North Atlantic and Greenland（SE–NW pattern, hereafter）. Moreover, for NAO-（NAO＋） events, the most marked decrease（increase） in the surface air temperature（SAT） in winter over northern Europe is in the decaying stage. For NAO＋events, the dominant positive temperature and precipitation anomalies exhibit the SW–NE-oriented distribution from western to northeastern Europe, which is parallel to the NAO＋-related blocking frequency distribution. For NAO-events, the dominant negative temperature anomaly is in northern and central Europe, whereas the dominant positive precipitation anomaly is distributed over southern Europe along the SW–NE direction. In addition, the downward infrared radiation controlled by the NAO＇s circulation plays a crucial role in the SAT anomaly distribution. It is further shown that the NAO＇s phase can act as an asymmetric impact on the European climate through producing this asymmetric spatiotemporal connection with the Euro-Atlantic IB frequency.展开更多
Oscillatory neuronal activity is the fundamental signature of neural networks.In the EEG literature,the oscillations are described as belonging to different frequency bands that are commonly used in clinical monitoring.
基金support from the National Natural Science Foundation of China (Grant Nos. 41505075 and 41790473)the National Key Research and Development Program of China (Grant No. 2016YFA0601802)
文摘This paper examines an asymmetric spatiotemporal connection and climatic impact between the winter atmospheric blocking activity in the Euro-Atlantic sector and the life cycle of the North Atlantic Oscillation（NAO） during the period 1950–2012. Results show that, for positive NAO（NAO＋） events, the instantaneous blocking（IB） frequency exhibits an enhancement along the southwest–northeast（SW–NE） direction from the eastern Atlantic to northeastern Europe（SW–NE pattern, hereafter）, which is particularly evident during the NAO＋decaying stage. By contrast, for negative NAO（NAO-）events, the IB frequency exhibits a spatially asymmetric southeast–northwest（SE–NW） distribution from central Europe to the North Atlantic and Greenland（SE–NW pattern, hereafter）. Moreover, for NAO-（NAO＋） events, the most marked decrease（increase） in the surface air temperature（SAT） in winter over northern Europe is in the decaying stage. For NAO＋events, the dominant positive temperature and precipitation anomalies exhibit the SW–NE-oriented distribution from western to northeastern Europe, which is parallel to the NAO＋-related blocking frequency distribution. For NAO-events, the dominant negative temperature anomaly is in northern and central Europe, whereas the dominant positive precipitation anomaly is distributed over southern Europe along the SW–NE direction. In addition, the downward infrared radiation controlled by the NAO＇s circulation plays a crucial role in the SAT anomaly distribution. It is further shown that the NAO＇s phase can act as an asymmetric impact on the European climate through producing this asymmetric spatiotemporal connection with the Euro-Atlantic IB frequency.
文摘Oscillatory neuronal activity is the fundamental signature of neural networks.In the EEG literature,the oscillations are described as belonging to different frequency bands that are commonly used in clinical monitoring.
