共查询到19条相似文献，搜索用时 109 毫秒
1.
青藏三江源区蒸发量遥感估算及对湖泊湿地的响应 总被引：4，自引：0，他引：4
青藏三江源区湖泊湿地变化一直以来备受关注,气候因素被认为是湖泊湿地变化的主要影响因素.与温度和降水资料相比,气象站获取蒸发量数据比较困难,而遥感技术却为估算区域地表蒸发量提供了一条新的途径.基于地表能量平衡原理,结合MODIS卫星数据和研究区气象资料,建立三江源区蒸发量估算模型,分析研究区内蒸发分布规律,并探讨温度、降水量、风速和蒸发量之间的相关关系,最后分析蒸发量对源区湖泊湿地变化的响应.研究结果表明:三江源蒸发量呈增加趋势,区域蒸发量随水热、植被覆盖和海拔高度差异而变化;研究区蒸发量受温度和降水量影响较大;蒸发量增大是三江源区湖泊萎缩和湿地退化的主要影响因素. 相似文献
2.
作为长江、黄河、澜沧江的发源地,三江源区是我国重要的水源涵养区和生态屏障。在气候变化背景下,三江源区广泛分布的冻土显著退化,对植被变化与生态环境产生深远影响,但近20年植被变化特征及其对气候与冻土变化的响应尚不明晰。基于2001—2020年间三江源区植被、气象与土壤冻融数据集,分析了过去20年间三江源区植被物候变化特征及其对气候因子与土壤冻融要素变化的响应。结果表明：三江源区归一化植被指数(NDVI)整体呈东南高、西北低的空间格局,2001—2020年间三江源区植被整体呈变绿趋势,生长季NDVI以每10年0.017的速率显著增加;植被物候显著变化,生长季延长[6.3 d·(10a)-1],主要由生长季开始日期(SOS)提前[4.9 d·(10a)-1]贡献。基于统计分析结果,气温和降水是生长季NDVI最重要的主导因素,植被对降水的敏感性在气温相对较高、降水相对较少的暖干区域更强;生长季开始前的降水是SOS最重要的主导因素。土壤冻融变化对植被生长的影响具有空间异质性,在暖干区域,土壤融化时段延长对植被生长起到抑制作用。总体来看,三江源季节冻土区... 相似文献
3.
1981-2006年西北干旱区NDVI时空分布变化对水热条件的响应 总被引：5，自引：1，他引：4
气候是植被变化的重要驱动因子. 利用1981-2006年GIMMS归一化植被指数（NDVI）时间序列数据,结合68个气象站降水、气温数据和DEM地形数据等资料,研究分析了西北干旱区植被活动的年、季变化和空间差异. 结果显示：在1981-2006年的26 a,西北干旱区植被的覆盖率增加了4.5%,年平均NDVI增加了3.2%;植被的生长季延长,主要表现在生长季的推迟. 从总体来说,植被覆盖率、生长季和NDVI值在2000年以前显著增加,而在2000年以后都呈现减小的趋势;其中,减少明显的区域是在伊犁河谷、中天山及平原区,在河流上游山区或源头以及部分河流两岸呈现增加态势;在年际变化上,大部分区域的气温、降水与NDVI相关性不强. 而年平均气温在4.58 ℃以下低温区和年降水在180 mm以上的相对湿润区,气温和降水都呈现正相关;在季节变化上,NDVI值在春季和秋季与温度相关显著,而夏季与降水相关性强. 2000年以后,植被覆盖率和NDVI值开始出现降低趋势与气温持续升高、降水量增幅下降有关. 相似文献
4.
为了解森林退化的原因,利用2000-2015年的MODIS NDVI数据,在分析贵州省植被变化趋势的基础上识别了归一化植被指数（NDVI)显著下降的区域,并在NDVI显著下降区选取面积大于10 km2的森林图斑为兴趣区,分析其内气候变化趋势及对森林NDVI值的影响。研究表明:197个兴趣区主要分布在贵州省西北部的赤水—习水、东北部的梵净山和东南部的非喀斯特区域;区内春、夏季NDVI变化趋势与年NDVI值变化趋势一致,下降速率达到-0.01·yr-1,冬季与其他季节变化趋势相反,呈不显著升高趋势;区内春季和夏季气温升高显著,降水和日照时间无明显变化,整体气候变化呈暖干趋势;夏季温度升高是NDVI降低的主要驱动因素。 相似文献
5.
为了了解气温、降水量和人类活动对流域植被NDVI(normalized difference vegetation index)的影响，以长江流域为研究区，运用一元线性回归分析法和Theil-Sen Median趋势分析法研究了长江流域气温、降水量和植被NDVI变化特征，同时利用相关分析法和残差分析法探讨气温、降水量和人类活动对植被NDVI变化的影响.结果表明:1960—2015年长江流域年平均温度显著上升，而降水量的变化趋势并不显著；1982—2015年流域NDVI呈显著增加趋势；1982—2015年流域NDVI与气温的相关性较高，然而与降水量的相关性并不显著；人类活动使流域NDVI增加的区域主要分布于流域北部、东南和西南部分地区，而使NDVI下降的区域位于流域中西部区域和长三角地区.气温对长江流域植被NDVI变化的影响大于降水，气候变暖和人类活动对流域生态环境具有一定程度的影响. 相似文献
6.
新疆博斯腾流域湿地遥感监测及时空变化过程 总被引：4，自引：0，他引：4
博斯腾流域是新疆最大的湖泊湿地分布区。湿地作为干旱区的一种特殊景观类型,在流域生态环境和水循环中发挥了重要的作用,其产生和消失、扩大和萎缩对区域生态环境将产生重要的影响。以Landsat系列数据为主要数据源,完成了博斯腾流域的3期遥感制图(1990、2000、2010年),分析了博斯腾流域湿地分布现状,探讨了区域湿地的时空变化过程和动态变化特征。结果表明:新疆博斯腾流域的湿地面积总体上一直在萎缩,1990-2010年总面积减少了16.24%;但是减少趋势相对变缓,且不同类型的湿地变化过程有所不同。其中:1990-2000年河流湿地和湖泊湿地表现为增加趋势,芦苇沼泽湿地表现为减少趋势;2000-2010年河流湿地、芦苇沼泽和湖泊湿地面积都表现为萎缩。在变化动态特征上,流域河流、湖泊湿地最近20a呈现倒"V"型波动,而芦苇沼泽湿地则持续下降。通过湿地变化与区域生态环境因子耦合分析表明,在近期内人类活动是造成区域湿地萎缩的主要因素。 相似文献
7.
呼伦湖湿地气候变化及其对水环境的影响 总被引：11，自引：0，他引：11
利用呼伦湖湿地所在地区的气象站1961—2005年的气温、降水和蒸发量资料及呼伦湖区域1959—2006年的水体面积、水位深度、水质状况等资料,分析了气候变化及其对水环境的影响.结果表明:呼伦湖地区近45 a来的气候变化呈现气温升高、降水减少、蒸发量增大的暖干化趋势,其空间变化具有较好的一致性,地形是影响气候空间变化的主要因子;呼伦湖地区气候暖干化是造成水资源短缺和水环境恶化及周边地区生态环境荒漠化等问题的重要原因;显著的气候暖干化加速了湖水水面积减少、水位下降和水环境恶化. 相似文献
8.
青藏高原典型冰川和湖泊变化遥感研究 总被引：70，自引：18，他引：52
青藏高原冰川和湖泊变化是气候变化敏感的指示器,利用地形图、航空照片、TM卫星遥感资料和其它相关研究文献资料,分析了青藏高原典型地区的冰川和湖泊变化情况.结果表明:1960-2000年期间,在气温上升、降水增加、最大可能蒸散降低的背景下,研究区内不同地区湖泊的面积变化存在比较大的空间差异.以冰川融水为主要补给的纳木错和色林错地区的主要湖泊以扩大为主,而以降水为主要补给的黄河源地区的主要湖泊则基本上全面萎缩.研究区的冰川在1960-2000年期间以退缩为主,但各地退缩的幅度有较大的差异. 相似文献
9.
10.
在RS/GIS技术的支持下,以1956年航片绘制的1∶10万地形图、1990年前后TM遥感图像及2000年前后ETM遥感图像为主要数据源,结合柴达木盆地8个气象测站温度、降水资料,研究了柴达木盆地湿地的分布特点、近50年来的面积变化和相关气候背景。研究结果表明: 柴达木盆地年均温度和降水总体呈上升趋势,而增温更为强烈,年均降水量微弱增加,1990～2000年为明显的暖干时期;柴达木盆地湿地在1956～2000年特别是1990～2000年间总体萎缩趋势严重,盆地边缘区和较大河流附近湿地呈现波动变化,区域气候变化和人类活动应为研究区内湿地变化的主要因素,盆地中西部湿地萎缩主要受到温度升高、人类活动加剧等因素影响,盆地边缘湿地面积少量增加主要受到降水量增加的影响。 相似文献
11.
Based on GIMMS NDVI data of Qilian Mountains region during 1982-2006, using the maximum synthesis, mean method, slope analysis and correlation analysis, the spatial and temporal changes of vegetation cover and its correlations with climatic factors were studied in Qilian Mountains. The results showed that: ①Vegetation NDVI of Qilian Mountains increases from west to east in general, showing the distribution pattern of much more vegetation in east regions than in west regions; ②Vegetation NDVI of Qilian Mountains has generally increased in the past twenty five years, but there are obvious spatial differences, especially vegetation NDVI of middle and east regions increase obviously; ③There have been obvious differences on spatial variation of seasonal NDVI in the past twenty five years in Qilian Mountains, and the increased area of vegetation NDVI is the largest in summer, followed by autumn, spring, but the most reduced area of vegetation NDVI is in winter. The regions of increased vegetation NDVI concentrate on southern mountain of Qinghai Province and in Buha River Basin, while the regions of reduced vegetation NDVI concentrate on Wushaoling, Lenglongling and Daban mountain in each season; ④The correlations between monthly average vegetation NDVI and temperature and precipitation are very significant, which indicates that temperature and precipitation are the main factors affecting the change of vegetation NDVI in Qilian Mountains, but intensive human activities are also important factors affecting the change of vegetation NDVI in some areas. 相似文献
12.
The Hanjiang River Basin is the source area of the Middle Route Project of the South-to-North Water Diversion Project, and the vegetation coverage in this basin directly affects the quality of the ecological environment. This study is based on long time series of Moderate Resolution Imaging Spectroradiometer (MODIS) Normalized Difference Vegetation Index (NDVI) data synthesized over 16 days from 2000 to 2016 in the Hanjiang River Basin. Major climatic data (temperature and rainfall) and topographic data (elevation, slope, and aspect) are employed to analyze the driving forces of NDVI changes. The results demonstrate the following: for the 2000–2016 period, the average annual NDVI is 0.823, with a change trend of 0.025 year?1. The overall NDVI upstream is higher than that downstream. The average annual value of NDVI upstream is 0.844, with a change trend of 0.036 year?1, and that of downstream is 0.799, with a change trend of 0.022 year?1. The spatial distribution of NDVI was significantly increased in the area around the upstream section of the river and near the Danjiangkou Reservoir, and the distribution of NDVI around the central city was significantly reduced. The NDVI was positively correlated with temperature and rainfall, and the impacts differed among different regions. At elevations below 2000 m, the NDVI shows an increasing trend with increasing elevation, and at elevations exceeding 2000 m, the NDVI is negatively correlated with elevation. Slope is positively correlated with the NDVI. The influence of aspect on the NDVI was small. 相似文献
13.
基于遥感和地理信息系统技术,利用NOAA-AVHRR数据对我国最近18年(1982～1999)来的植被覆盖的动态变化进行了分析.结果表明:我国植被覆盖的动态变化受气候波动的影响十分显著,并且这种变化的区域性差异明显.18年来,NDVI减小的地区主要分布在西北地区和青藏高原,而NDVI增加的地区主要发生在东部地区;20世纪80年代和90年代的NDVI变化趋势之间存在较大差异;90年代NDVI减小的区域明显地比80年代增加,特别是西北干旱地区NDVI的下降趋势明显.我国珠江三角洲和长江三角洲地区是18年来植被覆盖下降趋势最明显的地区,表明快速城市化的影响. 相似文献
14.
The influence of water conveyances on restoration of vegetation to the lower reaches of Tarim River 总被引：2，自引：1，他引：1
Because of long-term stream-flow cut off in the lower reaches of Tarim River, environmental degradation has become the most
severe and widespread environmental problem in Tarim River basin. Nine ecological water conveyances to the lower reaches of
Tarim River made ecological environment change a lot. 3S technology was used to monitor dynamic change of ecology. However,
remote sensing area index cannot analyze ecological restoration degree of Tarim River precisely because the time of each water
conveyance is short, the change of vegetation area is not obvious, and there exists visual interpretation error. In this paper,
remote monitoring datum of high temporal resolution and high spatial resolution were used to research the relationships between
normalized difference vegetation index (NDVI) and the groundwater depth, between NDVI and the surface vegetation coverage,
and between the groundwater depth and the surface vegetation coverage. The growth and restoration of the vegetation in different
periods were evaluated by investigative analysis of the change trend of NDVI. The conception of relative restoration degree
was proposed and the response of vegetation restoration to the water conveyance was evaluated. The evaluation result suggests
that: first, the response of vegetation to the water conveyance concentrates within 1,000 m of both riversides, and the range
of influence becomes smaller along the lower reaches of Tarim River. Second, influenced by the groundwater recharge, the vegetation
coverage shows decreasing trend with the increase of off-river distance. Third, the vegetation coverage shows decreasing trend
along the watercourse influenced by the water consumption. Finally, in spatial, original scattered meadow of low coverage
transforms to high coverage gradually in research region. Vegetation response to the water conveyance expands to both sides
with the watercourse being the axis, and expanding scale increases continuously. 相似文献
15.
Topographic controls on vegetation index in a hilly landscape: a case study in the Jiaodong Peninsula, eastern China 总被引：2，自引：0，他引：2
Yetang Wang Xiyong Hou Maojian Wang Li Wu Lanlan Ying Yinyin Feng 《Environmental Earth Sciences》2013,70(2):625-634
This study examined topographic influence on spatial and temporal variability in the normalized difference vegetation index (NDVI) derived from the Satellite Pour l’Observation de la Terre-Vegetation at the regional and landscape scales in the Jiaodong Peninsula. The generalized additive models were used to quantify the spatial variation of NDVI attributable to local terrain and topographically related variables including altitude, exposure to incoming solar radiation, topographic wetness index, distance to the nearest stream and distance from the coast. NDVI distribution shows significant dependence on topography. The variables explained 38.3 % of variance in NDVI at the peninsula, and 30–45.3 % of variance in NDVI at the woodland, cropland, and grassland landscapes. At the Jiaodong Peninsula scale, NDVI is influenced primarily by distance from the coast. However, topographic wetness index has the most explanatory power for NDVI at the woodland, cropland, and grassland landscapes. Through a statistical nonparametric correlation analysis (Spearman’s r), the study indicates that spatial distribution of NDVI changes during the period 1998–2009 and future change trend of persistence determined by Hurst exponent is closely associated with topography and topography-based attribution. These results highlight the importance of topographic changes at landscape and regional scales as an important control factor on NDVI patterns. 相似文献
16.
为探索局域生态环境变化对桂林市整体生态环境状态的影响,选择漓江沿岸北从刘村南至街底共8个峰丛地貌区作为研究对象(编号为No.1~No.8),并以1986、1991和2006年3个时相的Landsat-5卫星影像的TM数据为信息源,采用基于ROI的定域定量遥感技术,结合地理与岩溶地质学资料,对这8个岩溶峰丛区的遥感生境指标即归一化植被指数NDVI和缨帽变换中的绿度分量TC2作定域提取和纵、横向分析(时间和空间变化分析)。研究表明,2006年岩溶峰丛区的NDVI和TC2最高,生态环境最好,1986年次之,1991年最差,表明在20世纪80年代末90年代初这一阶段里,由于桂林市经济高速发展而忽视环保,岩溶峰丛区的生境曾受到较不良影响,但进入本世纪以来已经得到了明显改善;在空间上各峰丛区NDVI大于4.0和TC2大于20的地块呈现斑状或条带状分布,且自1991年以来有向全区扩大的趋势。同一区域不同时间NDVI和TC2变化具有1991年低,1986年、2006年高的趋势,而同一时间不同区域NDVI和TC2也存在着差异,由好到差其关系为:No.5>No.4>No.3>No.8>No.7>No.6>No.2>No.1。 相似文献
17.
基于遥感分析的近20 a来人类活动对石羊河流域地表径流的影响研究 总被引：1，自引：0，他引：1
用归一化植被指数(NDVI)数据提取的农业绿洲NDVI累积作为人类活动因素综合,结合石羊河流域主要河流出山口水文站和下游控制站蔡旗水文站1981年10月至2003年9月平均径流资料,分析近20 a来人类活动,主要是中下游人工绿洲农业活动对石羊河流域地表径流的影响.结果表明: 近20 a来在出山口径流变化不大的情况下,下游蔡旗水文站的来水量明显减少;中游人工绿洲NDVI累积与蔡旗水文站径流量呈明显负相关,而与上下游径流差呈正相关,这表明可用NDVI累积数据代表人类活动因素分析其对径流变化影响的研究.1992年以后中游人工绿洲NDVI累积与上下游径流差相关关系明显好于1992年以前的关系,由此可见1992年以后人类活动对径流的影响要强于1992年以前.中游人工绿洲NDVI累积与上下游径流差呈正相关表明,中游人类活动直接导致下游径流量的减少,而下游绿洲NDVI累积的变化与下游河流来水量没有直接的关系,这可能与下游绿洲的发展依靠地下水的过渡开采实现,这种方式的绿洲发展可能难以长期维持.农业绿洲NDVI累积趋势分析表明,中游农业绿洲有向外扩张趋势,而下游民勤农业绿洲有东退西进之势. 相似文献
18.
高时空分辨率的自然资源指标数据对大尺度自然资源动态观测与趋势评估至关重要。大数据时代下的海量多源数据为数据高效融合利用提供了可能。以重构汉江流域归一化植被指数(Normalized Difference Vegetation Index,NDVI)数据为例,搭建了PostgreSQL自然资源时空大数据处理底层架构,集成了数据级融合法、特征级融合法和决策级融合法,基于机器学习算法构建了一套面向自然资源信息提取的多源异构数据智能融合技术,实现了多源数据的高效利用与特征空间优选。同时,重构了2000—2019年汉江流域NDVI 1 km逐年数据集,全面反映了汉江流域植被动态变化。研究结果可为地球科学时空大数据的高效提取与模拟分析提供科学参考,为定量核算林草资源禀赋规模、探究生态系统时空演变规律提供一种更精准、更便捷的技术手段。 相似文献
19.
X. M. Jin R. H. Guo Q. Zhang Y. X. Zhou D. R. Zhang Z. Yang 《Environmental Earth Sciences》2014,71(11):4889-4898
The spatial distribution of vegetation pattern and vegetation cover fraction (VCF) was quantified with remote sensing data in the Hailiutu River basin, a semiarid area in North China. The moderate resolution imaging spectroradiometer normalized different vegetation index (NDVI) values for 4 years from 2008 to 2011 and field observation data were used to assess the impact of climate factors, landform and depth to water table on vegetation distribution at large scale. In the VCF map, 74 % of the study area is covered with low and low–medium density vegetation, 24 % of the catchment is occupied by medium–high and high-density vegetation, and 2 % of area is bare soil. The relationship between NDVI and climate factors indicated that NDVI is correlated with relative humidity and precipitation. In the river catchment, NDVI increases gradually from landform of sand dune, eolian sand soil to river valley; 92.4 % of low NDVI from 0.15 to 0.3 is mostly distributed in sand dunes and the vegetation type is shrubs. Crops, shrubs and some dry willows dominate in eolian sand soil and 82.5 % of the NDVI varies between 0.2 and 0.35. In the river valley, 70.4 % of NDVI ranges between 0.25 and 0.4, and grass, dry willow and some crops are the main plants. Shrubs development of Korshinsk peashrub and Salix psammophila are dependent on groundwater by analyzing NDVI response to groundwater depth. However, NDVI of Artemisia desertorum had little sensitivity to groundwater. 相似文献