Understanding land-use/cover change process for land and environmental resources use management policy in Ghana

Accurate information on land-use/cover change is a critical input for natural resource use management policy decisions. In Ghana, however, land-use/cover change is premised on the assumption that there has been a historically simple, linear, and uniform degradation of vegetation across all landscapes. The Kintampo and neighboring districts have become a subject of intense debate as to the real nature of prevailing land cover changes .It is commonly assumed that there is ubiquitously progressive irreversible woody vegetation loss across the area. The paper reports on the process and amount of land-use/cover changes that have prevailed in specific localities across the area within a 10-year period. It is hoped this will improve understanding and management of land-use/cover change in Ghana. Remote sensing and Geographic information systems technologies were used for the investigation. A multi-site satellite imagery approach was adopted to ensure that inductive inferences could be made. The outcome of the study indicated that, in space and time, there have been significant land-use/cover changes. Variability in change was a constant, rather than occasional feature across these human dominated landscapes. The conversion and transformation processes indicated that the traditional land-use strategies are self-sustaining. Any effective land-use/cover management strategy should be built upon the existing traditional farming system knowledge and practices.     

Land use/cover change and driving force analyses in parts of northern Iran using RS and GIS techniques

To accomplish integrated watershed management and land use planning, it is necessary to study the dynamic spatial pattern of land use and cover change related to socioeconomical and physical parameters. In this study, land use and cover change detection was applied to the Lajimrood Drainage Basin in northern parts of Iran, an area characterized by rich and diversified agricultural and forest mosaic. The main of changes in the study area were forest–arable land transformation, which was only considered in this study. In order to detect these changes, at first, based on 1:25,000 digital topographic maps dated 1967 and 1994 and ETM⁺ satellite image dated 2002, land use map in these three dates were prepared. The results showed that the area with forest land use decreased about 3.2% in transition 1967–2002. Also, arable land increased about 36.9%. We suggested a method to analyze the driving forces and the spatial distribution of land use change. The maps of elevation, slope, and aspect were derived and classified by using digital elevation model (DEM). Also, the maps of distance from road, drainage network, and building area were selected as socioeconomical factors. These maps were overlaid and crossed with land use change map and land use change area ratio was computed. The results showed that the elevation, slope, and aspect were physical effective factors in land use changing. Also, by increasing the distance from building area and roads, deforestation rate was reduced.     

Land use change scenarios and associated groundwater impacts in a protected peri-urban area

Land use changes in peri-urban areas are usually associated with significant impacts on groundwater resources due to alteration of the recharge regime as well as through the establishment of pollution sources. Quantifying the aforementioned impacts and assessing the vulnerability of the groundwater resources is an important step for the better management and protection of the aquifers. In the present study, a physically based, distributed hydrologic model has been used to identify the impacts from specific land use change scenarios in the protected area of Loutraki catchment. A vulnerability assessment method has been also implemented to provide a decision support tool to the land planning authorities and also hydrologic mitigation measures for the sustainable development of the area have been proposed. The hydrologic impacts of the land use scenarios include a 5% reduction in the annual recharge of the study aquifer for scenario 1 (doubling of the current urban areas) and 7% decrease for scenario 2 (tripling of the current urban areas). Nevertheless, these impacts can be minimised if small-scale artificial recharge infrastructure is developed and the land planning measures suggested through the vulnerability and recharge maps will be followed.     

2000-2013年甘肃敦煌市土地利用变化及其驱动因素分析

将2000、2005、2010和2013年的土地利用类型数据与GIS技术结合,获取了甘肃省敦煌市近年来土地利用类型动态变化特征,并结合该地区的2000年以来社会经济和自然环境的资料,分析土地利用类型变化的驱动因素.结果表明：在2000-2013年期间,敦煌市城市化发展迅速,耕地、建设用地和水域面积明显增加,2000-2013年的14建分别增长了10.0%、42.2%和2.5%;草地和未利用土地面积呈减少趋势,分别减少了2.1%和0.1%;林地、沙地变化程度较小. 7种土地利用类型之间相互转换,主要的转移方向为草地、未利用土地向耕地转移,未利用土地向建设用地和水域转变.对影响土地利用变化的而主要驱动因素进行主成分分析,结果显示经济发展、国家政策等人类活动为主要的影响因素,自然因素为辅.     

Prediction of future situation of land use/cover change and modeling sensitivity to pollution in Edku Lake,Egypt based on geospatial analyses

GeoJournal - Assessing land use/cover (LULC) change in coastal lakes is an essential process for sustainable development. Edku Lake is one of the most important lakes in the northern part of Nile...     

Quantitatively analyze the impact of land use/land cover change on annual runoff decrease

Annual runoff in Luanhe river basin was detected a downward trend and caused water crisis in Tianjin, China. To quantify the decreased runoff volume, Mann–Kendall test and Pettitt test were employed to check whether there existed significant trend and change points for annual rainfall and runoff time series in Panjiakou reservoir basin and 8 sub-watersheds. It was found that the annual runoff time series had a significant downward trend at 5 % confidence level, and the change point was at 1979 in Panjiakou reservoir watershed. Then double mass curve of annual rainfall and annual runoff was plotted, and two lines were fitted before and after 1979, respectively. Based on this method, the comprehensive effects of land use/land cover change on annual runoff were estimated. To further quantify the contributions of each main factor to annual runoff decrease, water stored in check dams and social water use in different periods were surveyed first. And then multi-linear regression was used to develop the relations between annual runoff and the driven factors. Water area decrease was identified to be the main factor contributing to annual runoff reduction. The results in this study can provide valuable information for water resources planners and policy makers.     

Waterlogging risk assessment based on land use/cover change: a case study in Pudong New Area,Shanghai

Waterlogging induced by torrential rain or typhoon in urban areas due to rapid urban development and land cover changes has been a global hotspot and a potential risk affecting urban habitant lifelines and safety. This paper analyzed the impact of land use/cover change on the surface runoff and evaluated the waterlogging risk caused by precipitation with different intensities in Pudong New Area, Shanghai. A simplified urban waterlogging model has been built for the inundated water depth simulation through the combination of both SCS model and GIS spatial analysis with the consideration of underlying surface characters in urban area. Based on the simulated depth results, waterlogging risk ranks were further established to evaluate waterlogging risk of Pudong New Area under different conditions considering social survey results. The results show that the land use structure and pattern change increases surface runoff depth. Under the assumption of a daily maximum precipitation at 200 mm, the surface runoff depth increased by 13.19 mm from 1994 to 2006 due to urbanization. On the whole, Heqing, Huaxia tourism area, Chuansha, Tangzhen and Jichang Town have high waterlogging risk rank, Gaoqiao, Donggou, urban district, Jinqiao, Caolu, Sanlin and Beicai Town have medium waterlogging risk rank, and Zhangjiang, Gaodong and Huamu Town have low waterlogging risk rank. These results provide important information for the local government, and the method of waterlogging risk assessment can also be applied in other cities to provide guidance on waterlogging risk control.     

大通河流域土地利用/覆被变化的水文响应

以大通河流域为研究区域,利用1985年和2005年土地利用数据,结合SWAT分布式水文模型定量评估了流域土地利用/覆被变化的水文效应。结果表明：1985-2005年大通河流域的土地利用变化主要表现为草地向耕地、居工地转变,草地所占比例由46.7%骤降至20.9%,而耕地面积由1985年的1065.8km²增加到2005年的3243km²;相较于1985年的土地利用情景,2005年土地利用情景下的模拟的多年平均径流增加了1.92×10⁸m³,由于上中下游主要的土地利用/覆被变化不同,导致流域径流变化增加程度由西北至东南逐渐增大;大通河流域年径流的增加主要表现为汛期径流增加,讯期月平均径流增幅达到了0.40×10⁸m³·mon^-1;非汛期径流则呈不明显减小趋势,平均降幅为0.024×10⁸m³·mon^-1。合理规划大通河流域土地利用方式,提高水源区涵养能力,对流域水资源可持续发展具有重要意义。     

Land cover and land use change related to shrimp farming in coastal areas of Quang Ninh,Vietnam using remotely sensed data

Rapid development of shrimp farming may lead to unrecognized and undesirable changes of land cover/land use patterns in coastal areas. Of special concern is the loss of mangrove forest in coastal areas such as Quang Ninh, Vietnam, which is adjacent to the World Heritage-listed Ha Long Bay. Understanding the status and changes of land cover/land use for coastal shrimp farms and mangrove forests can support environmental protection and decision-making for sustainable development in coastal areas. Within this context, this paper uses the 1999/2001 Landsat ETM+ and the 2008 ALOS AVNIR-2 imagery to investigate the contraction and expansion of shrimp farms and mangrove forests in coastal areas of Ha Long and Mong Cai, which now have a high concentration of intensive and semi-intensive shrimp farms. Images were separately analyzed and classified before using post-classification comparisons to detect land cover/land use changes in the study area. The results of this study found that the area of mangrove forest has been reduced by an estimated 927.5 ha in Ha Long and 1,144.4 ha in Mong Cai, while shrimp farming areas increased by an estimated 1,195.9 and 1,702.5 ha, respectively, over the same period. The majority of shrimp farms in Mong Cai were established at the expense of mangrove forest (49.4 %) while shrimp farms in Ha Long were mainly constructed on areas previously occupied by bare ground (46.5 %) and a significant proportion also replaced mangroves (23.9 %). The remarkable rate of mangrove loss and shrimp farming expansion detected in this study, over a relatively short time scale indicate that greater awareness of environmental impacts of shrimp farm expansion is required if this industry is to be sustainable, the important estuarine and coastal marine ecosystems are to be protected over the long term, and the capturing and storing of carbon in mangrove systems are to be enhanced for global climate change mitigation and for use as carbon offsets.     

Land use and land cover change and implication to watershed degradation by using GIS and remote sensing in the Koga watershed,North Western Ethiopia

Information on use/land cover change is important for planners and decision makers to implement sustainable use and management of resources. This study was intended to assess the land use land cover (LULC) change in the Koga watershed. The MSS of 1973, TM images of 1986, 1995 and 2011 were used together with survey and demographic data to detect the drivers of land cover changes. The result revealed that a remarkable LULC change occurred in the study area for the past thirty eight years. The area of cultivated and settlement has increased by 7054.6 ha, while, grass and bush lands decreased by 4846.5 and 3376 ha respectively. Wetland also declined from 580.2 ha to 68.3 ha. The growing demand for cultivable land and fuel wood were the major causes to the deterioration of grass and bush lands. Hence, the appropriate land use policy should be employed to sustain available resource in the watershed.     

Potential impact of climate change on snow cover area in the Tarim River basin

Two data sets, annual temperature and precipitation time series from 19 observation stations in the Tarim River basin covering 1958 through 2002, were investigated by non-parametric tests to detect the trend and features of climate change and variability. Based on these data, the snow cover area (SCA) in situ for the period 1982–2001 was further analyzed to examine the effect of climate change on snow. The results showed that both the temperature and precipitation had a jump in the mid 1980s and significantly increased in winter and summer, respectively. The SCA of the entire basin showed a slowly increasing trend. Responses of the SCA to temperature and precipitation in the northern, western and southern regions showed that the effect of precipitation on SCA is larger than that of temperature. In vertical direction, the SCA in the zone below 2,500 m a.s.l. kept a slow increase, but that in the zone above 2,500 m a.s.l. was inching down. Comparatively, the lower altitude zone was apt to be affected by precipitation, while the higher altitude zone tended to be influenced by temperature. The mid zone from 2,500 to 5,000 m was the area most sensitive to and affected by climate change. Compared with that in the 1980s, both the snowing and melting rates were higher in the 1990s. Correlation analysis implied that the SCA change in the cold season was positively correlated with the contemporary precipitation change, but had no strong correlation with the contemporary temperature change.     

托木尔峰国家级自然保护区土地利用/覆被变化及驱动力分析

利用保护区的3期Landsat TM遥感影像数据,运用GIS技术并结合区域生态环境质量指数,对托木尔峰自然保护区土地利用/覆被变化及其驱动力进行分析。结果表明:近27 a来,冰川和草地面积持续增长,增幅分别为12.37%和99.36%;水体和荒地面积持续减少,减幅为23.07%和12.15%;林地前阶段(1989-2003年)减少16.77%,后阶段(2003-2016年)增加57.91%。区域土地利用/覆被综合动态度,前阶段为0.39%,后阶段为0.36%;前阶段转化率为21.95%,后阶段转化率为18.91%。水体、草地和林地的转化率较高,冰川和荒地的转化率较低;尽管土地利用/覆被类型内部结构变化较复杂、频繁,但各类型之间相互转换的活跃程度逐渐趋于平缓。研究区生态环境质量指数呈增长趋势,年均增长率为0.31%,生态环境逐年改善。致使研究区生态环境质量改善的主要驱动力为气候的变暖湿和土地利用政策的改变。近27 a来,研究区中高山带降水量的增加,扩大了保护区冰川雪地的面积;晋升为国家级自然保护区后的土地利用政策,有效遏制了人类活动对保护区土地利用/覆被的影响,进而使生态贡献率较低的荒地转化为生态贡献率高的林草地,提高了区域生态环境的质量。     

Land use/land cover classification of the vicinity of Lake Chad using NigeriaSat-1 and Landsat data

Lake Chad in Africa experienced severe droughts in the 1970s and 1980s and overexploitations of water resulting in a decline of water level in the Lake and surrounding rivers. Such droughts and overexploitation of water caused a significant change of land use and water management practices over the last 50 years. Understanding the change of land use and land cover is, therefore, crucial to understand disturbance of the water cycle around the Lake. The present study analyzed satellite images of Lake Chad from Landsat-MSS, Landsat-TM, and NigeriaSat-1 to investigate the change of land cover during three time periods: the 1970s, 1991, and 2006. Unsupervised and supervised classifications were performed for the land cover analysis. The overall accuracies of the classification of Landsat-TM and NigeriaSat-1 are 93.33 and 95.24 %, respectively. It is evident that a 35 % decrease of waterbodies occurred from the 1970s to 1991, but a slight increase of 0.9 % occurred between 1991 and 2006. The Shrubland has overtaken most of the waterlog areas, as much as seven times of what it was in the 1970s. The interpretation of NigeriaSat-1 images indicates that NigeriaSat-1 has similar capabilities to Landsat-TM and Landsat-MSS for the detection of various land cover types because land cover and land use features are discernible on the processed images, especially depletion of waterbodies and vegetation. These are similarities justify the quality of the NigeriaSat-1 images for land cover and land use analysis.     

滦河流域土地利用/覆被变化的水文响应

以滦河流域为研究区,利用1985和2000年土地利用数据,结合SWAT分布式水文模型定量评价了流域土地利用/覆被变化的水文效应,并分析了流域地表径流变化与主要景观类型的响应关系。结果表明:SWAT（Soil and Water Assessment Tool）模型可以较好地模拟滦河流域的月流量过程,在研究区具有较好的适用性;1985—2000年流域林地向草地和耕地的转变导致流域年均地表径流和总径流量分别增加了12.6%和5.1%;并使得流域年均地表径流变化空间差异显著,整体呈增加趋势,且主要受到林地变化的影响,而在三道河子以上集水区地表径流的变化则主要受到耕地景观的影响。合理规划土地利用格局,对于流域水资源可持续利用具有重要意义。     

Land use change increases flood hazard: a multi-modelling approach to assess change in flood characteristics driven by socio-economic land use change scenarios

Natural Hazards - We analysed in the work how change in land use/land cover influences on flood characteristics (frequency and magnitude) using a model inter-comparison approach, statistical...     

典型喀斯特石漠化地区植被动态监测与土地利用变化的影响分析

基于2001至2014年MOD13Q1数据集、数字地面高程数据以及中梁山地区多期土地覆盖数据,进行植被覆盖度（FVC）估算及其变化趋势模拟、多期土地利用转移矩阵分析,探讨中梁山地区植被覆盖度动态变化特征、土地利用的时空变化特征以及土地利用和地形同植被覆盖度间的响应机制。研究结果表明：中梁山76.69%的区域为植被改善区,退化区面积占总面积的10.12%,存在明显的改善趋势,生态情况得到良好恢复;人类活动对中梁山区域影响方式主要表现为耕地向林地和建设用地转化的特点;植被生长趋势的空间异质性与坡度有关,坡陡区植被改善面积约为退化面积的14倍,缓坡区仅为7倍;植被退化现象受人览活动的影响较大,而人类晃动对植被改善影响较小,植被改善主要与植物的自然生长演替有关。     

Land use/land cover change impact on groundwater quantity and quality: a case study of Ajman Emirate,the United Arab Emirates,using remote sensing and GIS

Ajman is a rapidly urbanizing emirate with land development succeeding at a fast pace. This study aims to monitor land use/land cover changes and assesses the impact of these changes on groundwater quality and quantity of the shallow aquifer using multitemporal remote sensing data and geographic information system (GIS). To monitor the land use/land cover changes, the Spectral Angle Mapper (SAM) and the Normalized Difference Vegetation Index (NDVI) algorithms were utilized. The obtained maps were correlated against a set of total dissolved solid (TDS); Mg, Cl, and NO₃ groundwater quality index; and depth to the groundwater table maps constructed from groundwater data. The spatial analysis revealed a sharp depletion in groundwater quality and quantity related to the increase in the land use/land cover classes. The mean total TDS is from 21,971 to 26,450 mg/L and depth to groundwater level from ?12.33 to ?17.2 m over a period of 15 years. Maps of normalized difference and groundwater quality sustainability showed that the eastern side of the study area has a high value of groundwater quality sustainability and normalized difference, while the western side of the study area has a minimal value of groundwater quality sustainability and normalized difference. This study is of great assistance for decision makers and land developers to relate to municipal land allotment in rapidly developing regions such as Ajman.     

基于CLM模式的青藏高原土壤冻融过程陆面特征研究

使用位于青藏高原东部若尔盖站的观测数据驱动CLM3.5模式,设计一组去除模式中冻融过程的"退化试验",进行为期一年的模拟研究。通过对比原试验与敏感性试验模拟结果,初步分析冻融过程在土壤温度变化、各能量通量分配中的作用,得到以下结论：（1）冻融过程是土壤温度变化的"缓冲器",冻结过程向周围环境释放能量减缓了土壤降温的速率,使土壤温度不至降得太低,而消融过程从周围环境吸收能量减缓了土壤升温的速率,使土壤温度不至升高太多;（2）冻融过程改变了地表辐射通量,土壤冻结改变了地表反照率,改变了向上短波辐射,且由于冻结过程减缓了地表温度的下降,改变了地表向上长波辐射,进而改变了净辐射通量;（3）冻融过程显著地改变了陆面能量的分配,通过相变能量的释放和吸收增大了地气间能量的传输,显著地增大了地表土壤热通量,且通过改变地表温度和地表蒸发,改变了感热及潜热通量。在冻结过程及完全冻结阶段,感热及潜热通量均增大,但在消融过程阶段,感热及潜热通量均减小。冻融过程对土壤热通量及感热通量的影响在冻结过程及完全冻结阶段更为显著,而对潜热的影响则是在消融过程阶段更为显著。     

伊通河流域土地利用变化及其生态响应

通过遥感影像解译获取伊通河流域1986、1996、2005和2017年土地利用数据,采用土地利用动态模型、土地利用度和生态系统服务价值等方法,研究伊通河流域土地利用变化特征及其生态响应。研究结果表明,耕地、城镇建筑用地和林地是伊通河流域主要的土地利用类型,1986—2017年间,研究区土地利用综合动态度降低,土地利用度上升,土地利用结构趋于稳定。在31年间,生态系统服务价值整体下降33.97%,林地、草地、湿地和水域面积的减小导致生态系统服务价值显著降低。