霍林河中游径流量序列的多时间尺度特征及其效应分析

霍林河是松嫩平原西部地区科尔沁、向海和查干湖湿地的重要补给水源。通过对其中游白云胡硕水文测站46a的年径流量序列的多时间尺度分析,探讨霍林河径流演变的近似周期性,识别霍林河径流变化对其下游洪泛湿地水源补给的规律,以及这种规律控制下的洪泛湿地环境演变。小波分析表明,霍林河白云胡硕水文站年径流序列主要存在3个尺度的周期变化,不同时间尺度下周期信号的强弱在时频域中的分布具有较强的局部特征,以大于30a尺度的年代际周期变化起主导作用,该尺度下,霍林河径流演变呈现出丰、枯、丰的交替振荡,下游洪泛湿地景观演变相应表现出阶段性特征,1990年代以前尤为突出。能量相对较弱的中、小时间尺度径流量周期性变化,与强烈的人类干扰活动相比,对下游洪泛湿地环境演变的作用效果不明显,突出表现在1990年代以后。

Multiple Time-scale Characteristics of Flow Variations in the Middle Huolin River and Corresponding Effects Analysis

Huolin River is one of the most important water supply sources for the Xianghai,Kerqin,and Chaganhu wetlands in the west Songnen Plain.A multiple time-scale analysis was used to analyze an annual flow series of 46 years of the Baiyunhushuo hydrologic station,which is located at the middle reaches of Huolin River.Our main objective was to discuss the periodic characteristics of the flow series,and examine the temporal patterns of the Huolin River recharging into floodplain wetlands in its lower reaches,and its corresponding effects exerted on downstream floodplain wetlands environmental evolutions.Wavelet analysis showed that the annual flow of Baiyunhushuo hydrologic station varied mainly in three time scales.The intensity of periodical signals of different time scales was strongly partially distributed in its time-frequency domain.More than 30 years interdecadal variation played a leading role in the temporal pattern,and showed a scale increasing tendency.At this scale,the flow of Baiyunhushuo hydrologic station in the Huolin river presented an alternative fluctuation of rain,draught and rain.Accordingly,the landscape of floodplain wetlands in downstream area presented a periodic feature,it is especially prominent before the 1990s.Compared with intense human activities,the periodic flow patterns of middle and small scales with relative low energy,have unobvious effects on wetlands environmental evolvement,it is especially distinctive after the 1990s.It should be noted that the dual actions of flow evolution of natural factors and human disturbances exerted influences of different degrees on flow signals in different periods.A further discussion should be made regarding the influencing factors,including precipitations,evaporations and human disturbances,for figuring out the reason and role of floodplain wetland landscape evolutions,thereby bringing forward scientific and feasible measures for the protection and restoration of wetland ecosystems.Rationally allocating and managing water resources,reducing river regulation and abstraction actions would be in favor of the protection of the existing wetlands ecosystem and the restoration of degeneration ones in the basin.