Remote sensing analysis of desert vegetation and its landscape changes: The case in middle reaches of Tarim River Basin, Xinjiang, China

Based on remote sensing information sources including B/W aerial photos of 1983,pseudo-color aerial photos of 1992 and JERS-1/OPS VNIR image of 1996, vegetation types ofYingbazha, in the middle reaches of the Tarim River Basin in Xinjiang, China are mapped usingARC/INFO and related software. The changes in vegetation areas and distribution conditions areanalyzed. As a result of natural and human influences, vegetation changes have temporal andspatial characteristics. According to the principles of landscape ecology and geographical informa-tion science, the landscape changes are indicated. Moreover, the remote sensing and GIS tech-niques are integrated to study vegetation and its landscape.     

Remote sensing analysis of desert vegetation and its landscape changes: The case in middle reaches of Tarim River Basin,Xinjiang, China

Based on remote sensing information sources including B/W aerial photos of 1983, pseudo-color aerial photos of 1992 and JERS-1/OPS VNIR image of 1996, vegetation types of Yingbazha, in the middle reaches of the Tarim River Basin in Xinjiang, China are mapped using ARC/INFO and related software. The changes in vegetation areas and distribution conditions are analyzed. As a result of natural and human influences, vegetation changes have temporal and spatial characteristics. According to the principles of landscape ecology and geographical information science, the landscape changes are indicated. Moreover, the remote sensing and GIS techniques are integrated to study vegetation and its landscape.

     

UAV Remote Sensing Information Acquisition and Analysis of MS5.4 Earthquake in Baicheng County,Xinjiang

以2021年3月24日新疆维吾尔自治区阿克苏地区拜城县M_S5.4地震为例,利用无人机进行灾区航拍,结合现场调查完成灾区地表破裂情况、建筑物毁坏程度、道路毁坏程度无人机遥感灾情获取与分析。研究结果表明,此次拜城地震产生长约5 km的地表破裂带,主破裂带具有左旋走滑特征,与主压应力场方向一致;受地震动、地表破裂、场地类型及土壤成分等因素影响,地表破裂带周边老旧砖木结构房屋不同程度受损,乡村道路不同程度破坏;此次地震造成的地表破裂和震害分布情况受断裂带控制。     

Vegetation succession in deglaciated landscapes: implications for sediment and landscape stability

Landscapes exposed by glacial retreat provide an ideal natural laboratory to study the processes involved in transforming a highly disturbed, glacially influenced landscape to a stable, diverse ecosystem which supports numerous species and communities. Large‐scale vegetation development and changes in sediment availability, used as a proxy for paraglacial adjustment following rapid deglaciation, were assessed using information from remote sensing. Delineation of broad successional vegetation cover types was undertaken using Landsat satellite imagery (covering a 22 year period) to document the rate and trajectory of terrestrial vegetation development. Use of a space‐for‐time substitution in Glacier Bay National Park, Alaska, allowed ‘back‐calculation’ of the age and stage of development of six catchments over 206 years. The high accuracy (89.2%) of the remotely sensed information used in monitoring successional change allowed detection of a high rate of change in vegetation classes in early successional stages (bare sediment and alder). In contrast, later successional stages (spruce and spruce–hemlock dominated forest) had high vegetation class retention, and low turnover. Modelled rates of vegetation change generally confirmed the estimated rates of successional turnover previously reported. These data, when combined with the known influence of terrestrial succession on soil development and sediment availability, suggest how physical and biological processes interact over time to influence paraglacial adjustment following deglaciation. This study highlights the application of remote sensing of successional chronosequence landscapes to assess the temporal dynamics of paraglacial adjustment following rapid deglaciation and shows the importance of incorporating bio‐physical interactions within landscape evolution models. © 2014 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd.     

Spatio-temporal changes in land cover and aquatic macrophytes of the Danube floodplain lake

The aquatic vegetation of ?í?ov Lake in the Danube floodplain, which is listed in the Ramsar Convention, was investigated to address three main questions: (1) how have landscape composition and the structures of the lake and its buffer zone changed from the mid-20th century; (2) how have species richness and the abundance of the aquatic macrophyte assemblage in this lake ecosystem changed over the last 34 years; and (3) which landscape metrics can best explain these temporal changes for floating-leaved macrophytes? Two methodological approaches, remote sensing and botanical field surveys, were applied. Historical (1949, 1970, 1990) and contemporary (2006) aerial photographs were analysed to determine land cover. Landscape configuration and structure were analysed using eight landscape metrics selected in advance to measure spatio-temporal changes and the fragmentation of the lake ecosystem and its corresponding buffer zone. The species diversity, abundance and distribution of true aquatic macrophytes were surveyed eleven times in five survey stretches between 1973 and 2007.At the landscape level, a decrease in the area covered by floating-leaved macrophytes, as well as an increase in open water surface and fragmentation of the land cover classes in the lake ecosystem, were recorded from 1949 to 2006. Overall, 30 true aquatic macrophytes were found from 1973 to 2007. Species richness did not change considerably, but the abundance of aquatic species fluctuated over the years. Three groups of true aquatic vegetation, based on common structural characteristics, were found in 1973–1983, 1989–2002, and 2004–2007 over the last 34 years. The landscape metrics NP, PD, LPI, and SHDI, which all express patterns of landscape fragmentation mostly indicate temporal changes in floating-leaved macrophytes.     

轻小型无人机在房屋建筑结构类型调查中的应用

房屋建筑结构数据是了解房屋抗震设防能力的基础,获取房屋建筑结构信息具有重要的现实意义。本文在简单介绍无人机遥感系统、房屋建筑信息无人机遥感调查技术流程的基础上,以全国多地多架次飞行任务为应用实例,对无人机照片进行筛选、姿态匹配、照片拼接、纹理映射等处理,获取了房屋建筑密集区的正射镶嵌图和三维场景模型,然后对房屋建筑结构类型进行目视判读,并与地面调查的真实结果比对分析,计算得到目视判读的准确率为91.17%,Kappa系数为0.80。结果表明,轻小型无人机轻便灵活,获取的三维场景模型能有效、直观、准确地进行房屋建筑结构类型判定,可弥补传统实地调查的不足,为评估大范围建筑物的抗震能力提供重要的参考依据。     

Mapping Potential Groundwater‐Dependent Ecosystems for Sustainable Management

Ecosystems which rely on either the surface expression or subsurface presence of groundwater are known as groundwater‐dependent ecosystems (GDEs). A comprehensive inventory of GDE locations at an appropriate management scale is a necessary first‐step for sustainable management of supporting aquifers; however, this information is unavailable for most areas of concern. To address this gap, this study created a two‐step algorithm which analyzed existing geospatial and remote sensing data to identify potential GDEs at both state/province and aquifer/basin scales. At the state/province scale, a geospatial information system (GIS) database was constructed for Texas, including climate, topography, hydrology, and ecology data. From these data, a GDE index was calculated, which combined vegetative and hydrological indicators. The results indicated that central Texas, particularly the Edwards Aquifer region, had highest potential to host GDEs. Next, an aquifer/basin scale remote sensing‐based algorithm was created to provide more detailed maps of GDEs in the Edwards Aquifer region. This algorithm used Landsat ETM+ and MODIS images to track the changes of NDVI for each vegetation pixel. The NDVI dynamics were used to identify the vegetation with high potential to use groundwater—such plants remain high NDVI during extended dry periods and also exhibit low seasonal and inter‐annual NDVI changes between dry and wet seasons/years. The results indicated that 8% of natural vegetation was very likely using groundwater. Of the potential GDEs identified, 75% were located on shallow soil averaging 45 cm in depth. The dominant GDE species were live oak, ashe juniper, and mesquite.     

吉兰泰盐湖典型地物波谱反射率特征及其遥感解译标志

１９９７年８－９月期间,预外调查了吉兰泰盐湖及其外围的２５个典型地物,并对其实地进行了１０个通道的光谱反射率测试。根据吉兰泰盐湖地物地学特征,可将所测得的２筱典型地物分为５类：植被、基岩、水体、化学沉积物和松散沉积物,通过对５类典型地物波谱反射率特征及其影响因素的研究,并依据彩红外航空图象和ＴＭ标准假彩色的成象原理,建立了吉兰泰盐湖遥感解译标志。     

活动断层填图中的航片解译问题

遥感技术和高精度遥感信息的进步,极大地推动了活动构造和地震地质研究的发展,各种遥感技术在最近几年活动断层填图工作中得到了广泛的应用.如何充分利用各种遥感技术,充分挖掘各种遥感信息以提高填图工作的效率和精度,引起了广大相关科技人员的重视.航空照片以其高精度和高直观性在所有遥感信息源中占据着重要的地位.20世纪中晚期,中国...     

Land cover changes based on plant successions: Deforestation,rehabilitation and degeneration of forest in the upper Dadu River watershed

The land use/cover classification system is the foundation for land use/cover change study. Remote sensing data were firstly used for land use and land cover classification in the United States in 1971 and the Anderson Classification System was proposed in 1976[1], which was put into use in mapping 1:250000 land use and land cover of the United States. A series of new land cover classification systems have been established in recent years through research projects such as FAO LCCS and Bi…     

Temporal and spatial variation and stability of the oasis in the Sangong River Watershed, Xinjiang, China

The unique ecological landscapes are composed of the mountain systems with the obviousvertical differentiation, vast natural desert systems, and oasis systems on which the human beings rely for the existence in the arid areas in West China. Oases are the …     

Quantifying the impact of landscape changes on hydrological variables in the alpine and cold region using hydrological model and remote sensing data

Quantifying the impact of landscape on hydrological variables is essential for the sustainable development of water resources. Understanding how landscape changes influence hydrological variables will greatly enhance the understanding of hydrological processes. Important vegetation parameters are considered in this study by using remote sensing data and VIC-CAS model to analyse the impact of landscape changes on hydrology in upper reaches of the Shule River Basin (URSLB). The results show there are differences in the runoff generation of landscape both in space and time. With increasing altitude, the runoff yields increased, with approximately 79.9% of the total runoff generated in the high mountains (4200–5900 m), and mainly consumed in the mid-low mountain region. Glacier landscape produced the largest runoff yields (24.9% of the total runoff), followed by low-coverage grassland (LG; 22.5%), alpine cold desert (AL; 19.6%), mid-coverage grassland (MG; 15.6%), bare land (12.5%), high-coverage grassland (HG; 4.5%) and shrubbery (0.4%). The relative capacity of runoff generation by landscapes, from high to low, was the glaciers, AL, LG, HG, MG, shrubbery and bare land. Furthermore, changes in landscapes cause hydrological variables changes, including evapotranspiration, runoff and baseflow. The study revealed that HG, MG, and bare land have a positive impact on evapotranspiration and a negative impact on runoff and baseflow, whereas AL and LG have a positive impact on runoff and baseflow and a negative impact on evapotranspiration. In contrast, glaciers have a positive impact on runoff. After the simulation in four vegetation scenarios, we concluded that the runoff regulation ability of grassland is greater than that of bare land. The grassland landscape is essential since it reduced the flood peak and conserved the soil and water.     

Optimum segmentation of simple objects in high-resolution remote sensing imagery in coastal areas

The optimum segmentation of ground objects in a landscape is essential for interpretation of high-resolution remotely sensed imagery and detection of objects; and it is also a technical foundation to efficiently use spatial information in remote sensing imagery. Landscapes are complex system composed of a large number of heterogeneous components. There are many explicit homogeneous image objects that have similar spectral character and yet differ from surrounding objects in high-resolution remote sensing imagery. Thereby, a new concept of Distinctive Feature of fractal is put forward and used in deriving Distinctive Feature curve of fractal evolution in multiscale segmentation. Through distinguishing the extremum condition of Distinctive Feature curve and the inclusion relationship of fractals in multiscale representation the Scalar Order is built. This can help to determinate the optimum scale in image segmentation for simple-objects, and the potential meaningful image-object fitting the intrinsic scale of the dominant landscape object can be obtained. Based on the application in high-resolution remote sensing imagery in coastal areas, a satisfactory result was acquired.     

A two-dimensional model for suspended sediment transport in the southern branch of the Rhine–Meuse estuary,The Netherlands

For the southern branch of the Rhine–Meuse estuary, The Netherlands, a two-dimensional horizontal suspended sediment transport model was constructed in order to evaluate the complicated water quality management of the area. The data needed to calibrate the model were collected during a special field survey at high river runoff utilizing a number of techniques: (1) turbidity probes were used to obtain suspended sediment concentration profiles; (2) air-borne remote sensing video recordings were applied in order to obtain information concerning the spatial distribution of the suspended sediment concentration; (3) an acoustic probe (ISAC) was used to measure cohesive bed density profiles and (4) an in situ underwater video camera (VIS) was deployed to collect video recordings of the suspended sediment. These VIS data were finally processed to fall velocity and diameter distributions and were mainly used to improve insight into the relevant transport processes, indicating significant erosion of sand from the upstream Rhine branch. For quantitative calibration of the model, the data from the turbidity profiles were used. Sedimentation and erosion were modelled according to Krone and Partheniades. The model results showed a good overall fit to the measurements, with a mean absolute error of 18 per cent (standard fault = 1 per cent), corresponding to concentrations of about 0·020 (upstream) to 0·005 kg m⁻³ (downstream). The overall correlation between observed and simulated suspended sediment concentrations was 0·85. The remote sensing video recordings were used for a qualitative calibration of the model. The distribution pattern of the suspended sediment on these photos was reproduced quite well by the model. However, a more accurate calibration technique is needed to enable the use of aerial remote sensing as a quantitative calibration method. Copyright © 1999 John Wiley & Sons, Ltd.     

地震前后景观格局的变化研究——以四川都江堰地区为例

景观是保护生态环境的关键所在,考虑地震灾害对景观格局的破坏影响,模拟景观格局在地震作用后的变化情况,对于找到景观设计脆弱点意义重大。提出地震前后景观格局的变化研究,以四川都江堰地区为研究对象,基于遥感图像、ArcGIS软件和Fragstats景观计算软件,以景观单元特征指数、景观格局指数作为指标,分析该地区在2007—2008年地震发生前后景观格局的变化,为该地区的震后重建以及未来的景观规划提供参考。     

无人机地震灾情监测系统在四川高原山区的应用研究

无人机地震灾情监测系统主要由无人机飞行平台、飞行控制系统、遥感系统、软件系统和无线电遥控系统等几部分组成,具有运行成本低、执行任务灵活性高等特点,是快速获取震后灾情信息的重要手段。结合四川高原山区的自然地理和气象条件,对无人机地震灾情监测系统在四川高原山区的应用进行了研究。该系统在高原山区的应用将在提升地震灾情现场勘查能力,迅速获取灾情信息,增加救灾工作的时效性,及为后期科学考察提供辅助信息等方面提供重要的技术支撑。     

面向地震应急的UAV快拼软件比较分析--以辽宁大连城岭村为例

无人机遥感技术系统作为新时期应急救援装备是震后快速获取灾情信息的重要手段,随着无人机的智能化、轻量化的影像处理软件的迅猛发展,无人机领域的应用也越来越广泛。本文选取了辽宁大连城岭村作为实验地点,以大疆精灵4pro无人机获取的1个架次308张照片作为实验数据,选取Pix4D、smart3D、photoscan三款无人机影像处理软件,以处理流程、耗时、正射精度、三维建模等指标作为测试指标对三款软件开展对比研究工作。研究结果表明,小型消费级无人机在飞控系统下的测量精度可达厘米级,处理流程方面从简到难依次为Pix4D、photoscan、smart3D,耗时方面从短到长依次为Pix4D、photoscan、smart3D,正射(dom)精度从高到低依次为Pix4D、smart3D、photoscan,三维建模精度从高到低依次为smart3D、Pix4D、photoscan,该实验结果不仅为搭建地震应急前后方指挥部数据处理平台建设提供技术支撑,同时还对使用此类无人机做行业应用及飞行参数设置提供参考意义。     

Expansion rate and geometry of floating vegetation mats on the margins of thermokarst lakes,northern Seward Peninsula,Alaska, USA

Investigations on the northern Seward Peninsula in Alaska identified zones of recent (<50 years) permafrost collapse that led to the formation of floating vegetation mats along thermokarst lake margins. The occurrence of floating vegetation mat features indicates rapid degradation of near‐surface permafrost and lake expansion. This paper reports on the recent expansion of these collapse features and their geometry is determined using geophysical and remote sensing measurements. The vegetation mats were observed to have an average thickness of 0.57 m and petrophysical modeling indicated that gas content of 1.5–5% enabled floatation above the lake surface. Furthermore, geophysical investigation provides evidence that the mats form by thaw and subsidence of the underlying permafrost rather than terrestrialization. The temperature of the water below a vegetation mat was observed to remain above freezing late in the winter. Analysis of satellite and aerial imagery indicates that these features have expanded at maximum rates of 1–2 m yr^‐1 over a 56 year period. Including the spatial coverage of floating ‘thermokarst mats’ increases estimates of lake area by as much as 4% in some lakes. Copyright © 2011 John Wiley & Sons, Ltd.     

Aerial photosieving of exposed gravel bars for the rapid calibration of airborne grain size maps

In recent years, fluvial remote sensing has seen considerable progress in terms of methods capable of system scale characterisation of river catchments. One key development is automated grain size mapping. It has been shown that high resolution aerial photography can be used to automatically produce grain size maps over entire rivers. However, current aerial grain size mapping procedures all require field calibration data. The collection of such data can be costly and problematic in the case of remote areas. This paper presents a method developed to remove the need for field based calibration data. Called ‘aerial photosieving’, this method consists of using the same very high resolution aerial imagery intended for grain size map production to visually measure particle sizes on‐screen in order to provide calibration data. The paper presents a rigorous comparison of field‐based photosieving calibration data and aerial photosieving calibration data. Statistical tests are used to demonstrate that aerial photosieving gives similar results when compared with field‐based data with only a slight systematic overprediction. The new aerial photosieving method therefore simplifies the overall procedure required for the production of grain size maps and thus improves the cost‐effectiveness and potential availability of this new fluvial remote sensing technology. Copyright © 2010 John Wiley &Sons, Ltd.     

Operational applications of remote sensing in hydrology: success,prospects and problems

Abstract

The use of remote sensing information in operational hydrology is relatively limited, but specific examples can be cited for determining precipitation, soil moisture, groundwater, snow, surface water and basin characteristics. The application of remote sensing in hydrology can be termed operational if at least one of two conditions are met: (a) the application produces an output on a regular basis, or (b) the remote sensing data are used regularly on a continuing basis as part of a procedure to solve a problem or make decisions. When surveying the various operational applications, simple approaches and simple remote sensing data sets are the most successful. In the data-sparse developing countries, many operational remote sensing approaches exist (out of necessity) that may not be needed in developed countries because of existing data networks. To increase the use of remote sensing in operational hydrology in developed countries, pilot projects need to be increased and information services must be improved. Increased utilization of GIS to combine remote sensing with other information will promote new products and applications. End user training must be improved by focusing on satellite data processing and manipulation. In developing countries the same improvements are needed plus some more basic ones. There is a need for international monetary assistance to establish long-term remote sensing data, improved database systems and image processing capabilities. There is also the need to set up innovative regional training centres throughout the developing world.