十七世纪以来华北中部夏季降水的特征、趋势与影响

本文通过华北中部12务夏季降水曲线的主成分分析，得到代表大区域的夏季降水变化的PPC-1序列．分析显示十七世纪的开始，华北中部是比较湿润的，中叶出现较大的波动，而下半叶降水较为正常；十八世纪整体较为湿润；十九世纪以来，降水呈现下降趋势且年际变化显著增大．谱分析结果显示，夏季降水具有23．8年、8．6年、7．0年和2—5年的显著周期．在假定人类活动强度和其他控制因素不变的情境下，未来4JD年（2011—2050AD），华北中部地区的夏季降水总体呈现显著下降的趋势．最后，通过分析降水变率与社会进程的时间耦合，认为近四百年来气候变化对中国农耕社会的稳定性具有显著影响．

Characteristics, Trend and Impact of Summer Precipitation Variability in North-central China since 1600 AD

Utilizing 12 proxies of summer precipitation in north-central China, a representative constructed to indicate the precipitation Variation since 1600 AD. The results show that： （1） during series is the 17th century, early period was wet, mid-15eriod was of great variation and late period was much normal; （2） the climate in 18th century was much wetter than others; （3） since 19th century, the variation of precipitation turned largely with a obvious descending. The spectral analysis shows the significant periods are 23.8 a, 8.6 a, 7.0 a and 2 - 5 a. Under the stable intension of human activities and other factors, it is predicted that in the future 40 years., an obvious descending of summer precipitation is observed. Finally, a temporary relation was examined between social vulnerability and precipitation variation, and a conclusion was that climate change has a important role in an agricultural society.