九江市中心城区下垫面变化及其径流响应

在快速城市化的大背景下,城市地区下垫面变化是影响径流过程的重要因素。以江西省九江市中心城区为例,解译并分析1987—2018年土地利用/覆被变化(land use and cover change, LUCC)特征,利用城市时变增益非线性模型研究不同下垫面条件下的径流特征。结果表明:1987—2018年九江市中心城区(浔阳区、濂溪区、柴桑区)不透水面比例从0.49%上升为10.58%;典型年降雨条件下径流系数从0.31增长到0.38;场次洪峰流量增加了10%。不透水面比例是研究区流量变化的主导因素,其他下垫面类型及降雨条件的变化加剧了产汇流过程的时变性和复杂性,而绿地和水体的调蓄作用将抵消一部分由不透水面扩张引起的径流增大效应。     

Effect of land use/cover changes on runoff in the Min River watershed

Quantifying and interpreting the impacts that land use/cover change (LUCC) have on hydrology at basin scales are of great significance for the sustainable development of watershed ecosystems, water resources, and land management. The Soil and Water Assessment Tool was used to establish the regional model. The Min River watershed was divided into 236 sub‐basins, and simulations showed the spatial distribution of runoff in each sub‐basin with GIS‐based image displays. We set five scenarios to investigate the negative hydrological effects characterized by reductions in the water yield. From 1995 to 2004, the effect of simulated mean annual runoff caused by LUCC was ?12.61 m³/s and the climate variability caused ?67.61 m³/s. From 2005 to 2014, the hydrological effect caused by LUCC was ?2.38 m³/s and the climate variability caused ?58.53 m³/s. The elevation, Shannon's diversity index, largest patch index, and interspersion and juxtaposition index were all characterized by strong relationships with the sub‐basin outlet flows (adjusted R² = 0.572) using multivariate stepwise regression analysis. Redundancy analysis further proved that the reduction in grassland has led to a decrease in vegetation dominance while large increase in cultivated and residential lands has led to a higher degree of landscape richness and fragmentation, which has caused the reduced water yield. The restoration of grassland vegetation, as well as urban and agricultural water usage should be the primary focus of flow recovery.     

页岩气开发面临的环保挑战及建议

以合肥市区为研究区、以2002和2007年两个时相的TM影像为数据源,分别选择5种端元,利用Matlab的非负最小二乘算法,进行线性波谱分离,经综合后进行差值运算得到植被、水体和不透水面丰度变化数据,经与高分辨率图像勾绘结果进行对比,证明该方法精度较高,在植被覆盖度方面精度高于原来的NDVI二分法,该方法可用于城市LUCC研究。     

LUCC的不确定性研究

空间数据的不确定性是普遍存在的现象,从客观世界本身的不确定性和人类引起的不确定性两个方面入手,探讨LUCC的不确定性,剖析了LUCC研究的整个技术路线的每一环节的不确定性,细化了空间数据的不确定性。     

KINEROS2 application for land use/cover change impact analysis at the Hulu Langat Basin,Malaysia

The impacts of land use/cover changes (LUCC) on a developed basin in Malaysia were evaluated. Three storm events in different intensities and durations were required for KINEROS2 (K2) calibration and LUCC impact analysis. K2 validation was performed using three other rainfall events. Calibration results showed excellent and very good fittings for runoff and sediment simulations based on the aggregated measure. Validation results demonstrated that the K2 is reliable for runoff modelling, while K2 application for sediment simulation was only valid for the period 1984–1997. LUCC impacts analysis revealed that direct runoff and sediment discharge increased with the progress of urban development and unmanaged agricultural activities. These observations were supported by the NDVI, landscape and hydrological trend analyses.     

向家坝水电工程影响下区域土地利用及景观格局变化

为研究向家坝水电工程建设对周围区域土地利用和景观格局变化的影响,本研究采用面向对象分类方法对水电站建设前(2006)与建设后(2017)两个时期的研究区遥感影像进行土地利用和景观格局变化分析,并以2006年为基准年,采用CLUE-S模型对研究区2017年"自然发展状态"下土地利用进行模拟,与2017年实际情形进行对比分析。研究结果表明:(1)2006-2017年间,在水电站外部工程和社会发展的双重作用下,水体面积大幅度增加,裸地得到开发利用,建筑区扩张,林地和耕地减少较多;(2)相较于"自然发展状态",水电工程影响下的建筑区面积略有下降,园地/草地面积下降且与林地之间交叉分布增多;(3)相较于"自然发展状态",水电工程影响下研究区景观格局变化表现出不同的特点:景观水平上,自然发展对研究区整体的聚集作用减弱;类型水平上,研究区景观格局呈现出三种趋势:耕地与园地/草地呈增强趋势,建筑区与裸地呈延缓趋势,林地呈相反趋势。     

Importance of spatially distributed hydrologic variables for land use change modeling

Land use changes have a pronounced impact on hydrology. Vice versa, hydrologic changes affect land use patterns. The objective of this study is to test whether hydrologic variables can explain land use change. We employ a set of spatially distributed hydrologic variables and compare it against a set of commonly used explanatory variables for land use change. The explanatory power of these variables is assessed by using a logistic regression approach to model the spatial distribution of land use changes in a meso-scale Indian catchment. When hydrologic variables are additionally included, the accuracies of the logistic regression models improve, which is indicated by a change in the relative operating characteristic statistic (ROC) by up to 11%. This is mostly due to the complementarity of the two datasets that is reflected in the use of 44% commonly used variables and 56% hydrologic variables in the best models for land use change.     

基于遥感影像多尺度分析技术的LUCC研究

基于遥感和地理信息系统技术研究土地利用／覆被变化（LUCC）目前普遍采用的方法，其中研究区不同时期遥感影像土地利用／覆被信息的获取是研究的关键，而传统的单一尺度的信息自动提取方式很难满足高精度LUCC研究的需要。为此，提出了以多尺度分析技术来提取土地利用／覆被信息的方法，并以江津市的LUCC研究为例，显示出这种方法的优越性。     

5.12 汶川地震重灾区土地利用变化遥感监测与分析

基于遥感技术,采用多步骤分层监督分类法,对5．12汶川地震重灾区地震前后土地利用分类进行调查;在此基础上利用GIS技术,对汶川地震重灾区2008年地震前后及2010年的土地利用情况进行统计分析。研究结果表明：5．12汶川地震对山丘区植被毁坏较为严重,在较陡坡和陡坡山地,地震及其引发的次生灾害导致植被面积降低,荒漠面积增加,森林覆盖类型向草地覆盖类型转变;到2010年3月,汶川地震重灾区灾后土地利用情况出现较为明显的恢复,森林面积增加,农田和聚落面积也有了明显的提高。     

利用Landsat影像构建河西绿洲土地利用信息图谱——以张掖市甘州区为例

基于地学信息图谱理论,结合GIS和RS技术,利用河西绿洲甘州区1975年、1987年、1999年和2009年四期Landsat影像作为土地利用信息提取的基础空间数据,构建了一系列土地利用信息图谱,通过图谱来分析研究区的土地利用时空变化规律。结果表明:1975年～2009年河西绿洲甘州区的土地利用发生了显著变化,耕地、建设用地和未利用地呈现出持续的增加态势,其中耕地主要来源于草地、林地和未利用地的转化;林地、草地和水域面积呈减小趋势,主要表现为草地退化、开垦为耕地。