LULC changes

  • 文章类型: Journal Article
    地下水资源受到城市化进程加剧导致的土地利用土地覆盖(LULC)动态的巨大影响,由于全球人口增长,农业和家庭排放。本研究调查了十年期LULC变化对地下水质量的影响,从2009年到2021年,人类和生态健康处于多样化的景观中,西孟加拉邦,印度。使用2009年479口井和2021年734口井的地下水质量数据,计算了最近提出的水污染指数(WPI)。基于机器学习的“经验贝叶斯克里格”(EBK)工具的地理空间分布表明水质下降,因为优质水类别的数量从30.5%下降到28%,污染水从44%增加到45%。ANOVA和Friedman检验显示了两年的年度水质参数以及组比较的统计学显着差异(p<0.0001)。Landsat7和8卫星图像用于使用机器学习工具对LULC类型进行分类,并首次与响应面方法(RSM)相结合,这表明地下水质量的变化归因于LULC的变化,例如,WPI与建成区呈正相关,村庄植被覆盖,农业用地,与地表水呈负相关,贫瘠的土地,森林覆盖。建成区扩大0.7%,乡村植被果园减少2.3%,伴随着地表水覆盖率减少0.6%,农田的2.4%导致优质水下降1.5%,污水类别增加1%。然而,通过生态风险指数(ERI)的生态风险在2021年表现出较低的风险,这归因于高风险潜在区域的减少。这项研究强调了使用GIS和RSM等一些先进的统计工具将LULC与水质变化联系起来的潜力,以更好地管理水质和景观生态。
    Groundwater resources are enormously affected by land use land cover (LULC) dynamics caused by increasing urbanisation, agricultural and household discharge as a result of global population growth. This study investigates the impact of decadal LULC changes in groundwater quality, human and ecological health from 2009 to 2021 in a diverse landscape, West Bengal, India. Using groundwater quality data from 479 wells in 2009 and 734 well in 2021, a recently proposed Water Pollution Index (WPI) was computed, and its geospatial distribution by a machine learning-based \'Empirical Bayesian Kriging\' (EBK) tool manifested a decline in water quality since the number of excellent water category decreased from 30.5% to 28% and polluted water increased from 44% to 45%. ANOVA and Friedman tests revealed statistically significant differences (p < 0.0001) in year-wise water quality parameters as well as group comparisons for both years. Landsat 7 and 8 satellite images were used to classify the LULC types applying machine learning tools for both years, and were coupled with response surface methodology (RSM) for the first time, which revealed that the alteration of groundwater quality were attributed to LULC changes, e.g. WPI showed a positive correlation with built-up areas, village-vegetation cover, agricultural lands, and a negative correlation with surface water, barren lands, and forest cover. Expansion in built-up areas by 0.7%, and village-vegetation orchards by 2.3%, accompanied by a reduction in surface water coverage by 0.6%, and 2.4% in croplands caused a 1.5% drop in excellent water and 1% increase in polluted water category. However, ecological risks through the ecological risk index (ERI) exhibited a lower risk in 2021 attributed to reduced high-risk potential zones. This study highlights the potentiality in linking LULC and water quality changes using some advanced statistical tools like GIS and RSM for better management of water quality and landscape ecology.
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  • 文章类型: Journal Article
    由于流域内许多元素之间的复杂关系,评估污染物负荷如何对土地利用/土地覆盖(LULC)的变化做出反应是一项具有挑战性的任务。然而,通过将水文建模与地理空间工具和多元统计相结合,可以减少将LULC变化和非点源(NPS)污染负荷连接到河流的困难。这项研究的目的是调查LULC变化对高度人类主导的集水区NPS污染负荷的长期影响,在埃塞俄比亚中部。在研究中,水文建模用于从多光谱Landsat图像中估计NPS参数,然后使用多元统计技术来提取主要的LULC类型,这些类型解释了1981年至2020年之间NPS负荷的差异。结果表明,该地区存在人类诱导的LULC变化,随着建筑和农业景观的增长(186.4%和5.8%,分别),灌木和林地正在减少(67.1%和41%,分别)。由于这些变化,硝酸盐(NO3)的浓度,总P,总N,有机氮,有机磷负荷分别增加了69.41、19.83、18.45、18.88和24.05%,分别。减少自然植被,以及农业集约化,是NPS污染物流失到地表水源的主要原因。结果还表明,污染养分与森林砍伐和农业用地扩张密切相关。应实施适当的适应战略,以最大程度地减少LULC在该地区的变化的负面影响。
    Evaluating how pollutant loads react to changes in land use/land cover (LULC) is a challenging task due to the intricate relationships among the many elements within a watershed. However, the difficulty in connecting LULC change and nonpoint source (NPS) pollution loads to streams may be lessened by combining hydrological modeling with geospatial tools and multivariate statistics. The objective of this study was to investigate the long-term effects of LULC change on NPS pollution loads in a highly human-dominated catchment, in central Ethiopia. In the study, hydrologic modeling was used to estimate the NPS parameters from multispectral Landsat images, and multivariate statistical techniques were then used to extract major LULC types that explain the variances of NPS loads between 1981 and 2020. The results demonstrated that there were human-induced LULC changes in the area, as the built-up and agricultural landscapes are rising (186.4% and 5.8%, respectively), and shrub and forest lands are decreasing (67.1% and 41%, respectively). As a result of these changes, the concentrations of nitrate (NO3), total P, total N, organic N, and organic P loads were increased by 69.41, 19.83, 18.45, 18.88, and 24.05%, respectively. Reductions in natural vegetation, as well as agriculture intensification, are the major contributors to the NPS pollutant losses to surface water sources. The result also revealed that pollution nutrients are strongly related to deforestation and agricultural land expansion. Proper adaptation strategies should be implemented to minimize the negative impact of LULC changes in the area.
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  • 文章类型: Journal Article
    干旱事件威胁淡水水库和农业生产力,特别是在降雨量不稳定的半干旱地区。这项研究评估了一种新技术,用于评估2018年至2022年气候变化背景下干旱对LULC变化的影响。利用了各种数据源,包括用于LULC分类的Sentinel-2卫星图像,来自CHIRPS和AgERA5数据库的气候数据,来自JAXAALOS卫星的地貌数据,和从MODIS数据得出的干旱指标(植被健康指数(VHI))。两个分类器模型,即梯度树增强(GTB)和随机森林(RF),进行了LULC分类的培训和评估,通过总体精度(OA)和卡帕系数(K)评估性能。值得注意的是,GTB模型表现出卓越的性能,OA>90%,K>0.9。在2018年至2022年期间,非斯经历了LULC在建成区扩张19.92%的变化,裸地增加34.86%,水体减少17.86%,农业用地减少37.30%。在农业LULC的变化之间观察到0.81和0.89的正相关,降雨,和VHI。此外,在2020年和2022年确定了轻度干旱条件。这项研究强调了人工智能和遥感技术在评估干旱和环境变化中的重要性,具有改善现有干旱监测系统的潜在应用。
    Drought events threaten freshwater reservoirs and agricultural productivity, particularly in semi-arid regions characterized by erratic rainfall. This study evaluates a novel technique for assessing the impact of drought on LULC variations in the context of climate change from 2018 to 2022. Various data sources were harnessed, encompassing Sentinel-2 satellite imagery for LULC classification, climate data from the CHIRPS and AgERA5 databases, geomorphological data from JAXA\'s ALOS satellite, and a drought indicator (Vegetation Health Index (VHI)) derived from MODIS data. Two classifier models, namely gradient tree boost (GTB) and random forest (RF), were trained and assessed for LULC classification, with performance evaluated by overall accuracy (OA) and kappa coefficient (K). Notably, the GTB model exhibited superior performance, with OA > 90% and a K > 0.9. Over the period from 2018 to 2022, Fez experienced LULC changes of 19.92% expansion in built-up areas, a 34.86% increase in bare land, a 17.86% reduction in water bodies, and a 37.30% decrease in agricultural land. Positive correlations of 0.81 and 0.89 were observed between changes in agricultural LULC, rainfall, and VHI. Furthermore, mild drought conditions were identified in the years 2020 and 2022. This study emphasizes the importance of AI and remote sensing techniques in assessing drought and environmental changes, with potential applications for improving existing drought monitoring systems.
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  • 文章类型: Journal Article
    这项研究的主要目的是使用子流域尺度的新型空间模型评估土地利用和土地覆盖变化(LULC)对水文成分的影响。土壤和水评估工具(SWAT)用于分析LULC对水文成分的长期影响。经过校准和验证的SWAT模型的结果表明,径流和实际蒸散量(ET)预计将经历最大的增长,秋季超过130%和90%,而预计在预计时间内,潜在蒸散量(PET)(-59%)和ET(-80%)的下降幅度最大。水文成分的影响,高程,LULC,然后,由于传统模型中普遍存在的多重共线性问题,四个新的空间模型考虑了亚流域水平的城市化和土地利用强度(La)对水产量(WYLD)的指标。特别是,Moran特征向量空间变化系数(MESVC)表明,LULC类别中的土壤类别和水文特性之间的横向流动预计将对子流域尺度上WYLD的空间波动产生统计上的显着影响。空间过滤的无条件分位数回归(SF-UQR)的结果证实了MESVC模型的发现,并进一步暗示,仅在较低分位数中,横向流动仍然是WYLD的统计显着贡献者(例如,对于低于0.25的分位数)。LULCs对WYLD的影响在统计学上低于水文成分的影响。
    The main objective of this research is to assess the impacts land use and land cover changes (LULC) on hydrological components using novel spatial models at sub-basin scales. The Soil and Water Assessment Tool (SWAT) was employed to analyze the long-term effect of LULC on hydrological components. The results of the calibrated and validated SWAT model demonstrated that run-off and actual evapotranspiration (ET) are expected to experience the largest increase, more than 130% and 90% in autumn, whereas the largest decrease is anticipated to occur in the summer and winter for potential evapotranspiration (PET) (-59%) and ET (-80%) by the projected time. The impacts of hydrological components, elevation, LULC, and an indicator of urbanization and land-use intensity (La) on water yield (WYLD) at sub-basin levels were then considered by four novel spatial models due to the problem of multicollinearity which is prevalent in traditional models. In particular, the Moran eigenvector spatially varying coefficients (MESVC) showed that the soil class out of LULC categories and lateral flow among hydrological properties are expected to have a statistically significant effect on spatial fluctuation of WYLD at the sub-basin scale. The results of spatially filtered unconditional quantile regression (SF-UQR) confirm the findings of the MESVC model and further implied that the lateral flow remains as a statistically significant contributor to WYLD only in lower quantiles (e.g., for quantiles lower than 0.25). The impacts of LULCs on WYLD were statistically lower than the effects caused by the hydrological components.
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  • 文章类型: Journal Article
    在过去的三十年里,伊斯兰堡-一个计划中的城市,和拉瓦尔品第-一个计划外的城市,经历了大规模的土地利用和土地覆盖变化。这项研究的主要目的是在计划和计划外城市的卫星图像和人口数据的帮助下,对1990年至2021年与人口增长和城市化有关的LULC变化进行比较评估和量化。分类为四个土地利用土地覆盖类别:建成,植被,裸露的土地,选择了水。采用最大似然算法和混淆矩阵进行分类和准确性评估。结果显示,从1990年到2021年,伊斯兰堡和拉瓦尔品第的建筑面积从5.7%(52平方公里)增加到25.7%(233平方公里),从3.7%(60平方公里)增加到14.1%(228平方公里),分别。其中,伊斯兰堡的裸露土地从42.2%(382km2)下降到18.1%(164km2),拉瓦尔品第的65.5%(1058km2)下降到32.1%(518km2)。伊斯兰堡的植被增长了4.7%,拉瓦尔品第的植被增长了24.5%。两个研究区域的地表水体减少。两个城市的人口增长均与建房阶层呈很强的正相关,与裸露土地阶层呈很强的负相关。这项研究的结果可能有助于在可持续发展目标的背景下更好地规划和管理土地利用土地覆盖和城市扩张的政策制定。
    For the last three decades, Islamabad - a planned city, and Rawalpindi - an unplanned city, have experienced massive land use and land cover changes. The main objective of this study was a comparative assessment and quantification of LULC changes in relation to population growth and urbanization from 1990 to 2021 with the help of satellite imagery and population data in planned and unplanned cities. For classification four land-use land cover classes: built-up, vegetation, bare land, and water were selected. Maximum likelihood algorithm and confusion matrix were employed for classification and accuracy assessment. Results revealed that built-up increased from 5.7% (52 km2) to 25.7% (233 km2) and 3.7% (60 km2) to 14.1% (228 km2) from 1990 to 2021 for Islamabad and Rawalpindi, respectively. Wherein the bare land decreased from 42.2% (382 km2) to 18.1% (164 km2) in Islamabad and 65.5% (1058 km2) to 32.1% (518 km2) in Rawalpindi. Vegetation showed an increment of 4.7% for Islamabad and 24.5% for Rawalpindi. Surface water bodies decreased in both study areas. Population growth showed a strong positive correlation with the built-up class and a strong negative correlation with the bare land class for both cities. The outcomes of this study may be helpful in policymaking for better planning and management of land use land cover and urban sprawl in the context of sustainable development goals.
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  • 文章类型: Journal Article
    全球人口增长和稀缺资源加剧了土地使用的竞争。尽管已经认识到气候变化的影响,LULC的转换仍然经常被忽视,并威胁到流域水文学。这主要发生在发展中国家,农业是他们粮食安全的关键来源。LULC的转化一直在危害水平衡成分并破坏生态系统。这项研究证明了SWAT在量化LULC变化对古德流域水平衡的影响中的应用。对2003年至2021年的影响进行了量化,分水岭经历了农业和定居点的增加,而森林,灌木丛,湿地下降了。SWAT+模型的基于时间序列的性能表明,与校准和验证期间观察到的模型相比,该模型更加重组,并且能够模拟水流。在这个长期评估中,该模型模拟了56.5%的径流变化,产水量65.2%,横向流量为21.6%,渗滤46.2%,回流76.4%,2003年至2013年ET为0.2%。此外,从2013年到2021年,水平衡的一些属性有所增加,径流量为34.3%,产水量2.3%,ET为4.5%,横向流量为72.6%。然而,由于定居点的增加,通过拦截减少渗透并将降雨转化为径流,渗滤和回流分别减少了45.6%和86.7%,分别。产水量和径流与LULC的变化呈线性关系,影响他们的最敏感的土地利用变化是农业,森林,和定居点。模拟结果表明,在第三次模拟中LULC变化的影响下,水平衡不足。此外,在第二次模拟中,径流表面的增加限制了地下水向土壤的补给量,并减少了回流和渗滤。
    Global population growth and scarce resources increase the competition for land use. Despite the fact that the impacts of climate change have been recognized, the conversion of LULC is still often neglected and threatens catchment hydrology. This is mostly seen in the developing world, where agriculture is the crucial source of their food security. The conversion of LULC has been jeopardizing water balance components and damaging ecosystem. This study demonstrates the application of SWAT+ in quantifying the impacts of LULC changes on the Guder catchment water balance. The impacts were quantified between 2003 and 2021, and the watershed experienced an increase in agriculture and settlement while forest, shrubland, and wetlands declined. The time-series-based performance of the SWAT + model shows the model is more restructured and capable of simulating streamflow compared to observed during calibration and validation. In this long-term evaluation, the model simulates changes in runoff of 56.5%, water yield of 65.2%, lateral flow of 21.6%, percolation of 46.2%, return flow of 76.4%, and ET of 0.2% between 2003 and 2013. Moreover, some attributes of the water balance have increased from 2013 to 2021, with runoff of 34.3%, water yield of 2.3%, ET of 4.5%, and lateral flow of 72.6%. However, as a result of increasing settlement, which reduces infiltration through interceptions and converts rainfall to runoff, percolation and return flow were decreased by 45.6% and 86.7%, respectively. Water yield and runoff show a linear relationship with changes in LULC, and the most sensitive land use changes that affect them are agriculture, forest, and settlements. The simulation results show a water balance deficit under the impacts of LULC changes in the third simulation. Furthermore, the increased surface of runoff has been limiting the amount of groundwater recharge into the soil and reducing return flow and percolation in the second simulation.
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  • 文章类型: Journal Article
    与历史上其他时间相比,野火现在的表现与频率不同,强度和受影响的生态系统。在巴西,在过去的十年里经历了前所未有的火灾。因此,防止和减少类似的灾难,我们必须更好地了解这种极端事件的自然和人类驱动因素。巴西潘塔纳尔是世界上最大的连续湿地,是一个复杂的环境系统。2020年,由于气候之间的协同作用,潘塔纳尔经历了灾难性的野火,消防管理策略不足,环境法规薄弱。在这项研究中,我们根据土地利用和覆盖(LULC)类别分析了潘塔纳尔地区火灾行为的最新模式和变化。使用MCD64A1V.6产品的BA和Landsat卫星的LULC数据评估了2000年至2021年之间火灾和土地覆盖变化的年际变化。我们的工作表明,在过去的二十年中,潘塔纳尔州的火灾在草原上比在其他土地覆盖类型中更频繁地发生,但2020年的火灾优先烧毁了森林地区。森林和草原上的大面积火灾更为频繁;相比之下,农田显示小斑块。结果突出表明,大规模分析不能反映不同的局部模式,因此需要分层和细化的研究。我们的工作有助于解开人为相关驱动因素的作用的第一步,即LULC更改,塑造潘塔纳尔生物群落的火势。这不仅对于预测未来的火灾活动至关重要,而且对于指导该地区的适当火灾管理至关重要。
    Wildfires are behaving differently now compared to other time in history in relation to frequency, intensity and affected ecosystems. In Brazil, unprecedented fires are being experienced in the last decade. Thus, to prevent and minimize similar disasters, we must better understand the natural and human drivers of such extreme events. The Brazilian Pantanal is the largest contiguous wetland in the world and a complex environmental system. In 2020, Pantanal experienced catastrophic wildfires due to the synergy between climate, inadequate fire management strategies and weak environmental regulations. In this study, we analyzed recent patterns and changes in fire behavior across the Pantanal based on land use and cover (LULC) classes. The inter-annual variability of the fire and land cover changes between 2000 and 2021 was assessed using BA from MCD64A1 V.6 product and LULC data from Landsat satellite. Our work reveals that fires in the Pantanal over the last two decades tended to occur more frequently in grassland than in others land cover types, but the 2020 fires have preferentially burned forest regions. Large fire patches are more frequent in forest and grasslands; in contrast, croplands exhibit small patches. The results highlight that a broad scale analysis does not reflect distinct localized patterns, thus stratified and refined studies are required. Our work contributes as a first step to disentangling the role of anthropogenic-related drivers, namely LULC changes, in shaping the fire regime in the Pantanal biome. This is crucial not only to predict future fire activity but also to guide appropriated fire management in the region.
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  • 文章类型: Journal Article
    Anthropogenic activities responsible for modifying climatic regimes and land use and land cover (LULC) have been altering fire behavior even in regions with natural occurrences, such as the Pantanal. This biome was highlighted in 2020 due to the record number of fire foci and burned areas registered. Thus, this study aimed to understand how changes in LULC and climate affect the spatial, temporal and magnitude dynamics of fire foci. The Earth Trends Modeler (ETM) was used to identify trends in spatiotemporal bases of environmental and climatic variables. No trend was identified in the historical series of precipitation data. However, an increasing trend was observed for evapotranspiration, normalized difference vegetation index (NDVI) and temperature. For soil moisture, a decreasing trend was observed. The comparison between the mean of the historical series and the year 2020 showed that the variables precipitation, temperature, soil moisture and evapotranspiration had atypical behavior. Such behavior may have contributed to creating a drier environment with available combustible material, leading to a record number of burned areas, about three million hectares (248%) higher than the historical average. The 2020 fire foci data were used in two types of spatial statistical analyses: Grouping, showing that 76% of the registered fire foci were at high risk of fire and; Hot and Cold Spots, indicating high concentrations of Hot Spots in the northern region of the Pantanal, close to Cerrado and Amazon biomes agricultural frontier. The results of the Land Change Modeler (LCM) tool evidenced a strong transition potential from the natural vegetation to agriculture and pasture in the eastern region of the Pantanal, indicating that this could be, in the future, a region of high concentration of fire foci and possibly high risk of fire. This tool also allowed the prediction of a scenario for 2030 that showed that if measures for environmental protection and combating fires are not adopted, in this year, 20% of the Pantanal areas will be for agricultural and pasture use. Finally, the results suggest that the advance of agriculture in the Pantanal and changes in climatic and environmental variables boosted the increase in fire foci and burned areas in the year 2020.
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  • 文章类型: Journal Article
    Evaluation of carbon sequestration in various land cover types is a valuable tool for environmental policies targeting towards minimization of CO2 emissions and climate change impacts. For the past few decades, remotely sensed information on land cover has been used as useful alternative to ground observations and has proved to be a robust tool for studying land use / land cover (LULC) changes. The present work deals with the assessment of land-cover changes in a Mediterranean country - Greece, where expected climate change impacts and desertification risk are stated to be severe. This work focused on the CORINE land cover inventory at a spatial resolution of 100 m from 1990 to 2018 and selected Landsat images at 30 m spatial resolution for 1990, 2000 and 2018. Results indicated that the dominant land-cover changes in Greece over the predefined 29-year period, are related to land transformation from Non-irrigated arable land to Irrigated areas, implying an intensification of agricultural practices. Natural grasslands lose a substantial part of their areas transforming into Sclerophyllus vegetation and Sparsely vegetated areas. Forests gain areas from Transitional woodland-shrub and Olive groves increase their extent indicating an overall transition to woody vegetation. Estimation of Vegetation Carbon Stocks indicated a moderate decrease in the 1990 decade followed by a significant increase up to 2012 and a slight decrease thereafter. Forests of all types are by far the most important carbon sinks. Possible implications of country\'s recent economic crisis were examined and results indicated that economic welfare of the country seems to favor certain land cover types such as Mixed Forests and Permanently Irrigated land, but also preservation of the Vegetation Carbon Stocks.
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  • 文章类型: Journal Article
    The climate and Land Use/Land Cover (LULC) changes evince the considerable impact on water balance components by altering the hydrological processes. So, the present work focuses on the evaluation of the combined impact of both the climate and LULC changes along with and without water storage structures on water balance components of the Krishna river basin, India under present and future scenarios with the help of Soil Water and Assessment Tool (SWAT). Sequential Uncertainty Fitting algorithm (SUFI-2) was used for the model calibration and validation, which were carried out at the Vijayawada gauge station. The coefficient of determination (R2) and Nash-Sutcliffe efficiency (NSE) values obtained during the calibration period were 0.63 and 0.61, respectively, whereas, in validation, these values were found to be 0.61 and 0.56, indicates satisfactory results. The results showed that the model simulations and performance were significantly influenced by the presence of water storage structures, whereas the LULC changes were effective at the sub-watershed level. Future LULC maps of 2025, 2055, and 2085 were simulated from the Cellular Automata (CA) Markov Chain model, and they were used along with future climate projections to investigate its impact on water balance components. The climate model projects an increase of water balance components specifically, surface runoff, streamflow, and water yield, except for evapotranspiration in the future. Whereas, the future LULC changes may influence in offsetting the streamflow 20 to 30% reference to the observed flow. Thus, LULC changes were significantly influenced the model simulations; therefore, it is essential to consider the LULC changes along with climate scenarios in climate change studies. Overall, the surface runoff, water yield, and streamflow may increase by 50% under Representative Concentration Pathway (RCP) 4.5, and they may double under the RCP 8.5 scenario by the end of the century.
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