基于遥感影像的上荆江典型洲滩植被适宜区分布特征研究  

Study on the distribution characteristics of suitable vegetation growth areas on typical sand bars in the upper Jingjiang River based on remote sensing images

作　　者：袁景耀 孙昭华[1] 李芷晴 周炜兴 陈立[1] YUAN Jingyao;SUN Zhaohua;LI Zhiqing;ZHOU Weixing;CHEN Li(State Key Laboratory of Water Resources and Hydropower Engineering Science,Wuhan University,Wuhan 430072,China)

机构地区：[1]武汉大学水资源工程与调度全国重点实验室,湖北武汉430072

出　　处：《水利学报》2024年第2期238-252,共15页Journal of Hydraulic Engineering

基　　金：国家自然科学基金项目(51879198);水利部三峡后续研究项目(12630100100020J005)。

摘　　要：江心洲滩是长江中游河漫滩重要组成部分,厘清洲滩上植被生长适宜区域的分布特征,以及这些区域所应满足的淹没频率临界条件,是生态护滩规划设计和三峡建库后洲滩植被变化预测的重要前提。本文选取上荆江关洲和突起洲分别作为卵石夹沙和沙质型洲滩的典型代表,基于Landsat遥感影像提取了1986—2002年的长时序洲滩淹水范围和植被信息,改进并利用水文特性与影像数据相结合的方法计算了滩面上不同位置的淹没频率和植被频率,分析了二者间的响应规律,确定了植被生长适宜区对应的淹没率条件。研究结果表明:两类洲滩上都存在低、高植被频率区像元相对集中,而中等植被频率区像元较为分散的规律,根据植被频率分布特征,可将滩面区域划分为高频次植被覆盖区、中频次植被覆盖区、过渡区和不适宜区,各区之间的植被频率临界值分别为80%、50%、20%;滩面不同位置的淹没频率是影响植被频率的主导因素,从长时期平均来看两类洲滩上的淹没频率-植被频率响应关系符合统一的Logistic曲线,根据该曲线可确定出各区域的临界淹没条件分别为年均18 d、43 d、92 d。在年均淹没天数大于92 d的区域内,随着淹没天数增加,植被频率迅速减少至10%以下。本文的方法和认识可为三峡建库后坝下游洲滩植被演替趋势预测提供参考。Mid-channel bars are important parts of floodplains in the middle reach of the Yangtze River.Clarifying the distribution characteristics of suitable vegetation growth areas on the bars and the critical conditions they should meet is a crucial prerequisite for ecological embankment planning and design,as well as vegetation changing trend prediction on the riverine floodplain after the operation of the Three Gorges Dam.In this study,Guanzhou Bar and Tuqizhou Bar,located in the Upper Jingjiang River,were selected as typical representatives of gravel and sand mid-channel bars,respectively.Long-time series of floodplain inundation and vegetation information from 1986 to 2002 were extracted based on Landsat remote sensing images.An improved method combining hydrological data and image data was used to calculate the inundation frequency and vegetation frequency of every pixel on the bar surface.The relationship between the two frequencies were analyzed,and the inundation frequency conditions for the suitable vegetation growth areas were determined.The research results indicate that both types of mid-channel bars have concentrated low and high vegetation frequency zones,while the medium vegetation frequency zone are more dispersed.Based on the distribution characteristics of vegetation frequency,the bar surface area can be divided into high coverage zone,medium coverage zone,transitional zone,and unsuitable vegetation zone,with the critical vegetation frequency thresholds of 80%,50%,and 20%,respectively.The inundation frequencies at different locations on the bars are the dominant factor affecting vegetation frequency.On average over a long period,the inundation frequency-vegetation frequency relationships on both types of bars follow a unified logistic curve.According to this curve,critical inundation conditions for each zone are determined as an annual inundation duration of 18 days,43 days,and 92 days,respectively.At locations where the annual average inundation duration exceed 92 days,the vegetation frequency rapidly

关 键 词：上荆江 江心洲 植被 遥感影像 淹没频率 临界条件 

分 类 号：TP79[自动化与计算机技术—检测技术与自动化装置]