平流层信号在冬季短期气候预测中的应用

摘要

平流层大气环流异常信号被认为对冬季对流层短期气候预测或中长期天气预报具有先兆性指示意义，但到目前为止，仍未真正用于短期气候预测。为了获取更多运用平流层环流异常信号预测对流层及地面短期气候的经验，该文利用北半球环状模（NAM）信号对2011—2012年冬季我国北方短期气候进行4次预测，并将预测结果与实况进行对比。在4次短期气候预测中，第2次和第3次预测结果与实况吻合很好：第2次成功预测了1月中旬到2月中旬我国东北和华北地区偏冷，第3次则成功预测了这种偏冷状态的持续。成功的主要原因是2011年12月—2012年2月平流层信号周期确定，且对流层和平流层之间动力耦合关系已经建立完全，平流层异常信号在该时段对流层和地面短期气候具有较强指示意义。%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 north-ern 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.