共查询到19条相似文献,搜索用时 453 毫秒
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草地退化一直是三江源主要生态问题之一,严重制约着三江源地区生态安全和经济发展。遥感技术可实现对草地资源大面积监测,因此可以及时掌握三江源地区草地动态变化情况,为三江源地区生态保护提供依据。本文基于Google Earth Engine遥感大数据云计算平台,以2007~2018年MODIS NDVI为数据源,采用像元二分模型对三江源地区草地覆盖度进行估算,分析草地覆盖度时空变化以及与覆盖度气候因子的相关关系。结果表明,2007~2018年三江源草地覆盖度总体呈增加趋势,草地退化得到好转,覆盖度空间分布差异显著,表现出东南高、西北低的特点。三江源地区草地覆盖度与降水相关性不明显,对温度因子的响应更为敏感。 相似文献
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三江源地区是青藏高原的腹心地带,是高原生态系统的典型,具有重要生态服务功能。采用压力-状态-响应模式,利用遥感、气象观测、统计年鉴等数据来源,选取20个指标,对三江源地区生态安全进行评价。 相似文献
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《国土资源遥感》2018,(4)
三江源地区草场生长状况对当地畜牧业的发展及三江源地区生态系统的平衡具有重要的影响,合理精确地估测草产量具有重要意义。针对该区域面积较大,地表结构较复杂的特点,应用MODIS产品数据预测该区域的草场产量,构建了三江源地区草产量的预测模型。使用2009年4月—10月6种MODIS产品数据(归一化差分植被指数、增强型植被指数、叶面积指数、光合有效辐射吸收比率、总初级生产力和地表温度),结合偏最小二乘回归(partial least squares regression,PLS)与多元线性回归理论实现6种产品草产量的遥感估算。基于构建的模型,使用2011年4月—10月间共140景数据开展应用试验,并将试验结果与三江源地区16个草地生态监测站对应时间的草产量实测数据进行对比分析。结果表明,基于MODIS的6种产品估测的草场草产量与实际地面测量的草产量之间有较好的相关性;与传统多元回归法相比,基于PLS的草产量估产模型具有较高的决定系数(0. 829~0. 878之间)和较低的均方根误差(约42. 457~93. 674 kg·hm-2之间)。 相似文献
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利用1975年MSS、2000年ETM+和2007年CBERS-02B共3期影像数据开展三江源地区土地沙化遥感调查监测,在此基础上重点分析了32 a来三江源地区土地沙化时空变化特征及其驱动力因素。三江源土地沙化总体表现为先增加后减少的过程,沙化土地主要分布于海拔相对较高的平缓高原面上的盆地内,且具有沿河、沿交通线分布的特点。2000年以前,气候暖干化和人为活动加剧造成了土地沙化日益严重,表现为总量在增加、程度在加重、空间分布变化频繁;2000年以后,气候暖湿化是土地沙化趋于改善的最主要因素。 相似文献
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《测绘通报》2015,(Z2)
利用32年来三江源地区1975、2000和2007年三期湿地遥感监测数据,详细分析了1975—2007年间三江源不同源区湿地面积的变化特点;依托于全气象资料(包括平均气温、最低气温、最高气温、20-20时降水量以及平均日照时数数据),对30多年来各个源区的气象气候因子变化规律进行了研究。采用分形分维方法,通过计算各个源区湿地景观分形分维值,定量分析了三江源不同源区的湿地资源分形结构特征。最后,采用传统统计学和地统计学相结合的方法,通过对32年来三江源不同源区湿地面积、湿地资源镶嵌结构与气象因子所反映的各源区气候变化趋势的相关性综合剖析,总结了各源区湿地面积和湿地资源镶嵌结构随气候变化的响应规律。 相似文献
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利用地理信息系统技术与层次分析法对东川区生态环境进行敏感性分析,本文共选取5个评价指标,首先对其进行单因子评价;然后基于GIS空间分析功能,将东川区综合生态敏感性分为5个等级;最后构建东川区综合生态环境敏感性分布图。研究结果显示:①5个生态评价因子中,坡度因子对东川区生态环境敏感性影响最大,权重值为0.36。根据对生态敏感性影响程度从大到小排序为:坡度、高程、土地利用、NDVI和水域缓冲区。②东川区生态环境敏感性总体偏高,极高敏感区与高敏感区共占区域总面积的44.17%;中敏感区占比最高,为26.1%;低敏感区和极低敏感区两者占比之和为29.73%。③东川区生态环境极高敏感区和高敏感区主要分布在西北部;极低敏感区和低敏感区主要分布在东北部及中部河谷地区。 相似文献
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Optimization of land use structure consists of economic and social and ecological optimization. Applying the minds of system engineering and principles of ecology, this paper presents such thoughts: the optimal forest-coverage rate calculated according to the reality of a district is set as main standard of ecological rationality in the district; through considering the value of ecosystem services of the land with GREEN equivalent (mainly cultivated land and grassland) and based on the rule, GREEN equivalent, this paper introduces the area conversion between woodland and cultivated land, also between woodland and grassland; this paper establishes a multi-dimension controlling model of optimization of land use structure. In addition, a multi-objective linear programming model for optimization of land use structure is designed. In the end, this paper tests and verifies this theory of ecological optimization, taking Qionghai city in Hainan Province as an example. 相似文献
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近年来,随着工业化和城市化进程的加快,生态破坏、环境污染、湖泊品质恶化等一系列环境问题日趋严重,高原湖泊作为生态环境的重要指示剂,已逐渐成为研究的重点。空间可视化技术特有的交互性、多维性和可视化多样性的本质,更能直观形象地体现高原湖泊的变化。本文以阿雅克库木湖为研究区域,基于GIS平台,利用Landsat遥感影像数据(包括MSS、TM和ETM影像),运用改进的湖泊边界矢量化提取方法和GIS空间可视化技术,对高原湖泊的变化规律进行了研究。结果表明,历年的湖泊变化规律表现为湖泊的面积随着年份的增大而逐渐增大,某一年内的湖泊变化规律表现为减-增-减的规律,其中在2月份达到最低,在10月份达到最高,这对于保护高原湖泊和环境、预测未来环境等具有重要意义。 相似文献
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Optimization of land use structure consists of economic and social and ecological optimization.Applying the minds of system engineering and principles of ecology,this paper presents such thoughts:the optimal forest-coverage rate calculated according to the reality of a district is set as main standard of ecological rationality in the district;through considering the value of ecosystem services of the land with GREEN equivalent(mainly cultivated land and grassland)and based on the rule GREEN equivalent,this paper introduces the area conversion between woodland and cultivated land ,also between woodland and grassland;this paper establishes a multi-dimension controlling model of optimization of land use structure,In addition,a multiobjective linear programming model for optimization of land use structure is designed.In the end,this paper tests and verifies this theory of ecological optimization,taking Qionghai city in Hainan Province as an example. 相似文献
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G. P. Obi Reddy A. K. Maji C. V. Srinivas S. Thayalan M. Velayutham 《Journal of the Indian Society of Remote Sensing》2001,29(1-2):3-16
In the present study, detailed field survey in conjunction with remotely sensed (IRS-1D, LISS-III) data is of immense help in terrain analysis and landscape ecological planning at watershed level. Geomorphologically summit crust, table top summits, isolated mounds. plateau spurs, narrow slopes, plateau side drainage floors, narrow valleys and main valley floor were delineated. The soil depth ranges from extremely shallow in isolated mounds to very deep soils in the lower sectors. Very good, good, moderate, poor and very poor groundwater prospect zones were delineated. By the integrated analysis of slope, geomorphology. soil depth, land use/land cover and groundwater prospect layers in GIS. 29 landscape ecological units were identified. Each landscape ecological unit refers to a natural geographic entity having distinctive properties of slope, geomorphology. soil depth, land use/ land cover and groundwater prospects. The landscape ecological stress zone mapping of the study area has been carried out based on the analysis and reclassification of tandscape ecological units. The units having minimum ecological impact in terms of slope, geomorphology, soil depth and land use/land cover were delineated under very low stress landscape ecological zones. The units having maximum ecological stress in the form of very high slopes, isolated mounds, table top summits and summit crust, extremely shallow soils, waste lands and very poor groundwater prospects were delineated into very high stress landscape ecological zones. The integrated analysis of remotely sensed data and collateral data in GIS environment is of immense help in evaluation of landscape ecological units and landscape ecological stress zones. The delineated landscape ecological stress zones in the watershed have been recommended for landscape ecological planning for better utilization of natural resources without harming the natural geo-ecosystem of the area. 相似文献
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M. G. Raghavendra Reddy G. P. Obi Reddy A. K. Maji K. Nageshwara Rao 《Journal of the Indian Society of Remote Sensing》2003,31(4):271-282
In the present study, an attempt has been made to analyse IRS-ID LISS-III satellite data in conjunction with field observations
for geomorphological mapping and pedo-geomorphological characterisation in Mohgaon area of Nagpur district, Maharashtra. Analysis
of satellite data reveals distint geomorphological units viz., plateau top, isolated mounds, linear ridges, escarpments, plateau
spurs, subdued plateau, rolling plains, pediments, narrow valleys and main valley floor. Soil profiles, studied on different
identified landforms, showed variation in site and morphological charactaristics. Moderate soil erosion occurs on plateau
top, isolated mouds, plateau spurs, rollinmg plains and pediments. Severe erosion was identified on escarpments and subdued
plateau and narrow valleys suffer very slight erosional hazards. Moderately well drained soils were found on rolling plains,
pediments, narrow valleys and main valley floor. Well drained soils were noticed on plateau top and plateau spurs. Very shallow
soils were found on the plateau top and isolated mounds. Shallow soils are found in linear ridges, escarpments, plateau spurs
and rolling plains. Moderately deep and deep soils are found on subdued plateau, pediments and main valley floor. The landform-soil
relatioinship reveals that the soils on the plateau top and isolated mounds are very shallow, well drained, clay textured.
The soils on the narrow valleys and main valley floor are deep, moderatly well drained, and clayey in texture. It also indicates
that landform-soil processes are governed by physiographic position, drainage, slope and erosion conditions of the area. The
present study reveals that the analysis of remotely sensed data in conjunction with field observations in GIS will be of immense
help in geomorphology mapping, analysis of landform-soil relationships and generation of their geo-spatial database. 相似文献
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遥感地质特征显示青藏高原北部,在澜沧江—温泉与东昆仑南缘—阿尼玛卿两条岩石圈断裂之间区域存在着4个正交叠加在早期北西—南东向构造地貌上的北东—南西向第四纪坳陷。其中西羌塘北部坳陷和长江源坳陷的地堑式裂陷地貌特征明显,而黄河源坳陷和若尔盖坳陷发育程度较低,但它们均是在青藏高原大陆构造变形的统一动力学背景下,地貌发生东西向伸展变形的产物。进一步研究表明,它们的形成不仅与青藏高原中南部所发育的近南北向裂谷具有同样的动力学意义,而且已成为影响该地区生态系统的主要因素。 相似文献
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《International Journal of Digital Earth》2013,6(6):534-549
The Qinghai-Tibetan Plateau plays an important role in global climate and environmental change and holds the largest lake area in China, with a total surface area of 36,900 km2. The expansion and shrinkage of these lakes are critical to the water cycle and ecological and environmental systems across the plateau. In this paper, surface areas of major lakes within the plateau were extracted based on a topographic map from 1970, and Landsat MSS, TM and ETM+ satellite images from the 1970s to 2008. Then, a multivariate correlation analysis was conducted to examine the relationship between the changes in lake surface areas and the changes in climatic variables including temperature, precipitation, evaporation, and sunshine duration. Initial results suggest that the variations in lake surface areas within the plateau are closely related to the warming, humidified climate transition in recent years such as the rise of air temperature and the increase in precipitation. In particular, the rising temperature accelerates melting of glaciers and perennial snow cover and triggers permafrost degradation, and leads to the expansion of most lakes across the plateau. In addition, different distributions and types of permafrost may cause different lake variations in the southern Tibetan Plateau. 相似文献