摘要:1978～2018年全国夏季降水实时业务预测技巧显示东北地区明显偏低，尤其是近几年在对全国夏季旱涝的总体分布预测效果明显提高的情况下，对东北地区的预测却与实况相反，因此有必要分析该区域预测技巧偏低的原因。利用站点资料、再分析格点数据、实时预测历史数据及统计诊断等方法，探讨了动力气候模式预测能力以及东北夏季降水预测的认识缺陷。通过系统地回顾东北夏季旱涝的气候特征、影响因子及预测方法等方面的研究进展，以及东北夏季降水实时预测检验，得出预测技巧偏低的可能原因：（1）东北初夏降水主要受东北冷涡活动的影响，盛夏主要受西太平洋副热带高压、东北南风和中高纬环流型的共同作用，而业务常用的国内外主要动力气候模式无法准确反映与东北初夏和盛夏降水相联系的关键环流系统；（2）东北夏季降水与全球海温的关系较弱且不稳定，尤其是与ENSO的关系较为复杂，年际关系随年代际变化而波动，即ENSO不是预测东北夏季降水的强信号；（3）东北夏季降水具有明显的季节内、年际和年代际等多时间尺度变率，夏季降水受到多种时间尺度信息的叠加和调控，不同尺度变率的贡献相当，且影响系统不同，导致预测难度较大。最后，进一步探讨了东北夏季降水预测存在的科学问题及可能的解决途径，以期为夏季业务预测提供参考。
关键词:东北夏季降水/
预测检验/
ENSO/
多时间尺度/
影响系统
Abstract:The real-time forecast accuracies of summer precipitation in Northeast China (NEC) from 1978 to 2018 were significantly low. Moreover, in the recent four years, when the prediction of the overall distribution of summer precipitation anomaly for the whole country was relatively accurate, the prediction of summer precipitation anomaly in NEC was contrary to the actual situation. Therefore, analyzing the cause for the low forecasting accuracy is necessary. In this paper, the forecasting ability of dynamic models and cognitive defects on forecasting summer rainfall in NEC are discussed. Moreover, by systematically reviewing the climatic characteristics, influencing factors, prediction methods of summer drought and flood in NEC, and the real-time forecasting skills, the causes have been obtained as follows: (1) The precipitation in early summer in NEC is mainly affected by the cold vortex activity in NEC, and in midsummer, it is mainly affected by the subtropical high in the West Pacific, the southerly wind in the Northeast, and the circulation pattern in the middle and high latitudes. However, the main dynamic climate models commonly used at home and abroad cannot accurately reflect the key circulation systems associated with precipitation in early summer and midsummer in NEC. (2) The relationship between the summer rainfall in NEC and the global sea surface temperature (SST) is weak and unstable. Especially, the influence of El Ni?o-Southern Oscillation (ENSO) on summer precipitation in NEC is complicated; the relationship between them varies from decade to decade. (3) The summer rainfall in NEC has remarkable multi-timescale variability (inter-seasonal, inter-annual, and inter-decadal timescales), influenced by different circulation systems, which makes accurately predicting summer precipitation in NEC more difficult. Finally, some scientific problems and possible solutions regarding summer rainfall forecasting in NEC are further discussed, which may be helpful for the future summer rainfall predictions in this area.
Key words:Summer precipitation over Northeast China/
Predicted test/
ENSO/
Different time scales/
Influence system
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