气候变化与建闸影响下小流域入海径流量长周期变化特征:以盐城海岸为例

河流入海通量是河口海岸地区物质能量循环的重要组成部分,也是地貌与环境演化的主要控制因素之一。以1957~2012年盐城海岸降雨量及主要建闸入海河流径流量等统计资料为基础,采用M-K趋势检验、小波分析等多种方法,研究了建闸活动影响下小流域入海径流量的长周期变化特征,对气候变化及海平面上升背景下的河口海岸治理具有重要意义。结果表明,受到降雨量减少及人类活动的影响,近60年来入海径流量呈下降趋势,减少速率为3×10~6 m~3(10 a)~(-1),径流量的季节性及年代际变化特征明显,以1965年为界,1965年前后时期的径流量统计特征差异显著。尺度变化方面,入海径流量具有多周期变化特征,其第一主周期为23.38 a,径流量及降雨量在不同周期尺度下表现出明显的"丰—枯"及"湿—干"交替震荡特征。此外,ENSO事件及河口建闸能够分别对入海径流量的年代际及季节性变化特征产生影响。未来需结合气候及下垫面变化特征开展入海径流量预测及相关影响评估。

The Long-Period Variation Characteristics of Water Discharge with Estuarine Sluice and Climate Change in a Small Watershed:A Case Study in Yancheng Coast

Discharge fluxes into the ocean are an important component of material and energy cycle in estuarine and coastal areas. They are also the primary controlling factor of morphological and environmental evolution. Based on statistical analysis of rainfall and runoff of tidal rivers with sluices at Yancheng coast from 1957 to 2012, the authors studied features of multi-scale changes in runoff affected by tidal sluices using M-K trend test and wavelet analysis, etc. Results of the present study have great implications for estuarine and coastal management under the influence of climate change and sea level rise. It is found that runoff into the ocean decreases at a rate of 3×10⁶ m³ (10 a)^-1, seasonal and decadal variability in runoff are obvious, and statistical characteristics of runoff differ greatly before and after 1965. Runoff variation displays a multi-scale feature, and the primary period is 23.38 a. Runoff and rainfall demonstrate alternating "high-low" and "wet-dry" conditions respectively at different scales. In addition, ENSO events and sluices at estuaries could affect the inter-annual, inter-decadal and seasonal variability of runoff. Runoff estimation and evaluation of runoff changes should be conducted in the future with consideration of climate and land surface changes.