Application of Stratospheric NAM Signal to Wintertime Climate Prediction

Stratospheric circulations are of planetary scales and long periods. It is considered that signals of stratospheric circulation anomalies could be used to predict tropospheric weather and climate systems in wintertime, but few practice is reported so far. To evaluate whether stratospheric signals can be used in long-term weather prediction or short-term climate prediction in wintertime, four intra-seasonal climate prediction experiments are carried out in winters of 2011 and 2012, using the index of stratospheric northern annular mode (NAM). Among the four predictions, the second and the third predictions successfully captured the polarity of NAM and surface temperature tendency in North China, which are well verified by observations in following weeks. The second prediction is particularly successful. The results suggest that stratospheric NAM signals are indeed useful for improving prediction skills for long-range weather or short-term climate variability in winter.