1766年以来永定河汛期径流量与太平洋年代际振荡

The Study for Relationship between PDO and the streamflow of Yongdinghe River(Lugouqiao) since 1766AD

以清代永定河芦沟桥志桩尺寸记录为骨干资料,结合近现代器测水文资料,使用分段建模的方法恢复了1766-2004年永定河芦沟桥断面的汛期径流量序列,序列表明永定河径流量在逐年尺度上具有极大的不稳定性,但其洪峰规模自19世纪以来不断减小,19世纪中期与20世纪初期是最为明显的丰水时段,而1920年代后径流量便明显萎缩,枯水期一直延续至现代。进入1920年代后,流量变化在18世纪后期至19世纪存在的30年准周期消失,水量变化呈现无周期特征。与太平洋年代际振荡指标PDO的比对发现,两者在30-40年尺度上具有明显的反相关关系,天然状态下,太平洋温度升高对应于永定河流域较为干旱的时段。海温异常造成的季风强度变化会导致华北地区降雨格局出现变化,进而影响到永定河芦沟桥以上河段的汛期水量,表明处于季风区北部边缘的永定河水系对于太平洋海温变动具有更大的敏感性。

In this article, based on the floodlevel record of Yongding river（Lugouqiao Bridge） and modern surveying data, combined with hydrological data, using segmented modeling method for the recovery of 1766--2004AD Lugou bridge section of Yongding river runoff sequence, sequence indicates that the Yongding river runoff in the year scale has great instability, but its peak scale continuously since nineteenth Century and in mid nineteenth Century and early twentieth Century, reduce, is the most obvious abundant water period, and after 1920s runoff in dry season is obvious atrophy, continued into the modern. After entering 1920 age, flow change in the late eighteenth Century to nineteenth Century in30 years quasi cycle disappear. The Pacific Decadal Oscillation Index （PDO） alignment found, both in 30--40scale has a significant inverse correlation between, the natural condition, the temperature corresponding to the Yongding River Basin in the relatively arid period. Sea surface temperature anomaly caused by monsoon intensity change will lead to changes in rainfall pattern in North China, and affect the Lugou bridge over Yongding River in flood season, showed in the monsoon region of northern edge of the Yongding river system for the Pacific SST changes with greater sensitivity. The atmospheric response, however, consists also of a wind stress curl anomaly that spins down the subtropical ocean gyre, thereby reducing the poleward heat transport and the initial SST anomaly, The ocean adjusts with some time lag to the change in the wind stress curl, and it is this transient ocean response that allows continuous oscillations. The transient response can be expressed in terms of baroclinic planetary waves, and the decadal timescale of the oscillation is therefore determined to first order by wave timescales. Advection by the mean currents, however, is not negligible.