在江淮流域,梅雨等降水异常引发的旱涝经常发生。作者对江淮流域的灾害背景、气候特征及其影响因子等作了分析,发现在近50年中,降水有明显的年际和年代际异常,20世纪80年代以后,该区的降水有显著增加的趋势。典型旱涝年降水异常的时空分布表明,引起降水异常的因子非常复杂,即使在同一年中,不同月份的异常型也可能有差别。对于不同年份,降水异常型更为不同。影响江淮流域降水异常的因子的作用,可通过数值模拟进行“分离性”研究,但由于模式的系统性误差,模拟结果也只有参考意义。因此,发展具有不同动力框架和热力过程的多种模式,仍是当前的重要任务。
Floods and droughts induced by the Meiyu anomaly often take place in the Yangtze-Huaihe River basin (YHB). In this paper the backgrounds of the flood and drought disasters, the climatological properties and the influencing factors of the Meiyu anomalies in the YHB are briefly analyzed. It is found that in recent 50 years the Meiyu amount has evident interannual and interdecadal variations. Since the 1980s precipitation has been increasing obviously in the YHB. Analysis of the temporal and spatial variations of rainfall anomalies in the typical flood and drought years shows that the factors influencing the precipitation anomalies are very complicated, so even in the same year the anomaly distribution patterns in different months are different, and for different years the patterns are more different. "Separate studies" may be carried out by use of numerical modeling for individual factors in order to depict their impacts on precipitation anomalies in the YHB. However, due to the model systematic errors the modelsimulated results are only for reference. Therefore, it is necessary to develop various numerical models with different dynamic frameworks and thermodynamic processes at present and in the future.