基于海气耦合环流模式的ENSO预测

摘要

Predictions of ENSO are described by using a coupled atmosphere-ocean general circulation model. The initial conditions are created by forcing the coupled system using SST anomalies in the tropical Pacific at the background of the coupled model climatology. A series of 24-month hindcasts for the period from November 1981 to December 1997 are carried out to validate the performance of the coupled system. Correlations of SST anomalies in the Nino3 region exceed 0.54 up to 15 months in advance and the rms errors are less than 0.9℃. The system is more skillful in predicting SST anomalies in the 1980s and less in the 1990s. The model skills are also seasonal-dependent, which are lower for the predictions starting from late autumn to winter and higher for those from spring to autumn in a year-time forecast length. The prediction, beginning from March, persists 8 months long with the correlation skill exceeding 0.6, which is important in predictions of summer rainfall in China. The predictions are succesful in many aspects for the 1997-2000 ENSO events.%利用一个大气大洋耦合环流模式做了ENSO预测研究。通过用实测的热带太平洋区域海表温度异常叠加到耦合模式模拟的气候海温上强迫预报模式得到了预测所需的初始场，在此基础上进行了系统性的时效为2年的后报试验，时间从1981年11月至1997年12月。对后报结果的检验表明，在预测的前15个月里，Nino3区海表温度距平总体预测相关技巧达到0.54以上，均方根误差不超过0.9°C。预测系统对80年代的ENSO现象具有较高的预测能力，而对90年代的ENSO事件，其预测水平相对较低。进一步分析表明，预测技巧具有季节依赖性，从秋末和冬季开始的预测相对较差而从春季到秋初开始的预测则很好。值得一提的是从每年3月份开始的预测，其0.6以上的相关技巧可达8个月，这对中国夏季降水预测是非常重要的。该预测系统对1997至2000年的ENSO现象的实际预测较为成功。