海河流域近500年大旱大涝时空特征及趋势预测

作者选择记录年代较长、系统性较好、分布均匀的十八个站作为海河流域的代表站，分别统计了近５００年及每世纪、各年代大旱大涝的出现频数，探讨了它的时空分布特征。还根据天文、气候背景制作了１９９５～２０１０年旱涝趋势预测。研究表明，１９９５～２０１０年海河流域大致处于太阳活动２３周的黑子低值位相和第２４周的高值位相之间，同时又处在太阳黑子世纪周期的下降段。从全国旱涝型指数和北京地区旱涝等级变化曲线看，目前海河流域正处于持续下降期，未来将进入湿润多雨阶段

TEMPORAL AND SPATIAL CHARACTERISTICS OF SEVERE DROUGHTS AND FLOODS IN HAIHE DRAINAGE BASIN IN THE LAST 500 YEARS AND FORECAST ON TENDENCY

Based on the length,continuity and spatial disribution,historical records from 18 stations located in Haihe drainage basin were selected as the standard stations of the basin.Using these records,the frequency of severe droughts and floods in each century and decade for the last 500 years was calculated.The temporal and spatial characteristics of severe droughts and floods were also analysed.According to astronomical and climatic background,forecasts on tendency of drought/flood were made for 1995 to 2010 using statistical method.The study shows that from 1995 to 2010 the activity of sun spots is to be in a period between its 23th period with low phase and 24th with high phase,but for century scale it is in decending period.From the changing pattern of droughts/flood index of China and the changing trend of drought/flood index of Beijing area,the studied basin is in the dry period at present.It is showing to be in moist period with more rainfall in the future.