黄河泛滥决口频率与历史气候变化相关性分析

Historical Bank⁃Breaching Frequency of the Yellow River in Relation with Climate Change

使用HHT时间序列分析方法研究了过去2000 a气候变化与黄河下游泛滥决口频率的关系,可以将其分为3个阶段:公元0—800年(隋唐前期以及之前),800—1000年(隋唐后期以及北宋前期),1000—2000年(北宋后期至今)。第1阶段内,黄河的泛滥决口频率几乎不受气温变化的影响。第2阶段内,天然植被破坏导致入黄沙量增加,泛滥决口频率升高,泛滥决口频率与气温正相关。第3阶段内,泛滥决口频率进一步升高,并且泛滥决口频率与气温存在明显负相关性,气温越低,泛滥决口频率越高,主要原因是:暖湿期,水量增大,河槽展宽,行洪能力强,不易发生决口;干冷期,水量减小,河槽萎缩,即使遇到水量不大的洪水,也极有可能发生泛滥决口。未来30 a黄河中游地区的平均地面温度将持续升高,年降水量呈增加趋势。未来暖期泛滥决口频率较小,有利于开展大型长期的河道整治活动:一方面加强黄河中游产沙区水土保持;另一方面通过水库联合调度,利用人造洪水冲刷河槽,尽量增加河槽过流面积,提高行洪能力,以防在下一个冷期中因河槽萎缩和极端洪水而造成溃决的严重后果。

The relationship between the bank⁃breaching frequency of the lower Yellow River and climate change in the past 2000 years was studied by Hilbert⁃Huang transform(HHT)method.This relationship could be divided into three stages:0-800AD(Early and before the Sui and Tang Dynasties);800AD-1000AD(Later Sui and Tang Dynasties and Early Northern Song Dynasty);1000AD-Now(After North⁃ern Song Dynasty).In the first stage,the bank⁃breaching frequency of the lower Yellow River was hardly affected by climate change.In the second stage,the bank⁃breaching frequency of the lower Yellow River was increasing because of vegetation destruction and at the same time it rose with the increase of the temperature.The second stage could be seen as the transition stage of the first and the third stages.In the third stage,the bank⁃breaching frequency of the lower Yellow River continued to grow.There was a significant negative correlation between the bank⁃breaching frequency and the temperature change.It could be explained by the Yellow River channel became shrunk during dry and cold periods so that when large flood came,bank⁃breaching was more likely to occur.In the next 30 years,the temperature of the middle Yellow River basin would keep on increasing.Precipitation was expected to increasing with less extent.The bank⁃breaching frequency would decrease in the future warm and humid climate,it was conductive to large⁃scale river regulation project.With the increasing of precipitation,the water and soil conservation could be enhanced on one hand;on the other hand,man⁃made⁃flood by reservoir cooperation dispatch could be used to broaden the channel.These measures could prevent serious consequences due to channel shrinkage and extreme floods in the next cold and dry period.