海面上升导致泄洪延时-子牙新河案例分析

Delay of flooding water discharge by sea level rise:a case study on Ziyaxinhe River

【研究目的】尽管人们普遍认为全球变化背景下的海面上升是海岸带环境变化的重要驱动因素,但对一个具体地区而言,仍缺少定量化的影响评估,以至于气候变化基础研究与海岸带实际经济社会活动之间存在日渐明显的脱节。本文是试图弥合这种脱节的一次探索。【研究方法】2023年夏秋京冀津地区大暴雨,达到了1963年之后60年一遇的量级,造成生命财产和区域经济的重大损失。本文根据子牙新河洪水闸口泄洪的具体案例,探寻海面上升潮位升高泄洪延时之间可能存在的因果关系。【研究结果】研究发现在21世纪海面上升背景下,渤海湾西岸存在潮位升高1 cm、泄洪时间减少0.02小时的潮位上升与泄洪延时之间的定量时空关系。【结论】提出潮位高于洪水位时不能泄洪的“临界点”概念,并根据联合国政府间气候变化专门委员会(IPCC)关于海面上升的最新预案,尝试做出了今后三个时间节点(2030、2040和2050年)的泄洪延时预测。

This paper is the result of flooding water discharge by sea level rise.[Objective]Although being well known that sea level rise under the global climate change is a major driving force of coastal environmental changes,it has long been an obvious gap between the fundamental researches concerned and the existing coastal socio-economical activities,especially the quantitative impact-estimation for a given coastal area.This paper is an approach to remedy such a rift.[Methods]Catastrophic rainfall in the July-August last year,triggered off an one-in-60-years flood in BeijingHebei-Tianjin region.With a process of the flooding-water-discharge in a sluice,we approach a cause-and-effect relationship between elevating tidal level and delays of flood water discharge.[Results]Under the forecast sea level rise in the 21st century,a spacious-temporal relationship between tidal level rise,following the sea level rise,and curtailed discharge time of flooding water as 1 cm versus 0.02 hour.[Conclusions]Thus,a concept of‘tipping point’of the tidal level being higher than the contemporaneous flood water is addressed and delaying discharge time scenarios for the three time nodes 2030,2040 and 2050 are estimated,respectively.