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1.
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
2.
The relationship between drought activity and vegetation cover in Northwest China from 1982 to 2013 总被引：1，自引：0，他引：1
Yelin Jiang Ranghui Wang Qing Peng Xiaoquan Wu Husen Ning Cheng Li 《Natural Hazards》2018,92(1):145-163
We investigated drought activity and the relationship between drought and vegetation in Northwest China over the period 1982–2013 using the standardized precipitation evapotranspiration index (SPEI) and the normalized difference vegetation index (NDVI). The indexes were, respectively, calculated from ground-based meteorological data and from remotely sensed satellite data. The spatial and temporal distributions of drought (SPEI) and of vegetation cover (NDVI) were compared using annual trends, and the relationships between these trends were analyzed. The results are: (1) Overall, Northwest China had a drought trend during the study period, although some a few regions show a significant wetness trend; (2) the mean annual NDVI fluctuates, but overall shows an increasing trend, particularly in some mountainous areas that have at least adequate water and vegetation cover, while unused land becomes degraded; (3) most regions show a positive correlation between SPEI and NDVI, although the western parts of the Tarim basin, Qaidam basin, and some regions in the southeastern part of study area show a negative correlation; and (4) the various regions respond differently to global climate change, but in general regions with more vegetation cover show increased vegetation growth, while regions with less vegetation cover are becoming degraded and thus more vulnerable to the adverse effects of climate change. 相似文献
3.
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
4.
近20余年来西北地区植被变化特征分析 总被引：27，自引：0，他引：27
利用1982—2003年8 km分辨率的NDVI数据集,选中国西北地区森林、草原、灌溉农业、雨养农业区不同类型植被为研究区,分析了植被年、年际变化特征,并对植被覆盖空间变化进行动态研究.结果表明:森林、草原、灌溉农业区和以春小麦为主的雨养农业区NDVI年变化为单峰型曲线,以冬小麦为主的雨养农业区NDVI曲线呈双峰型;同一类型的植被NDVI受纬度或海拔高度的影响,绿峰出现时间存在1个月的位相差.22 a来森林植被NDVI多呈下降趋势,草原植被区为上升趋势;雨养农业区变化不大,灌溉植被区呈显著的上升趋势.西北东部雨养农业区植被波动频率和幅度最大,是受降水影响最敏感的地区;森林植被次之;有灌溉条件的绿洲植被,年际间波动最小.22 a间西北地区植被以增加趋势为主,增加面积约为20.5%,主要分布在新疆和河西走廊绿洲、黄河沿岸灌区以及青海草区,水分条件充足的绿洲是NDVI增加最显著的区域;NDVI减少地区面积为4.77%,主要分布在西北东部. 相似文献
5.
承德是京津冀地区重要的水源涵养区和防风固沙区，是京津冀生态环境支撑区的重要组成部分，其植被状况将直接影响着区域生态环境质量的改善。基于MOD13Q1时间序列NDVI资料，利用线性回归分析法、像元二分法、稳定性分析法等测度承德市全域2000—2018年植被覆盖时空演变特征，并分析气候、地形等因素对植被覆盖的影响。结果表明:（1）承德市全域植被状况年际变化总体发生了改善，植被生长季夏季的NDVI值最高，月度变化中7月份NDVI值最大，多年均值达到0.775 2。（2）植被年际变化趋势显著性存在空间差异，植被指数极显著增加区域面积最大，占比59.08%，而极显著减少和显著减少的区域面积较小，分别占全域的0.76%和0.58%，主要分布在承德市中部、南部等地区。（3）承德市各区县植被覆盖状况均以较高覆盖度为主，面积达到45 585.69 km2。在多年植被覆盖度稳定性格局中，西北部波动较大，其余大部分地区稳定性好，波动较低。（4）承德市NDVI受5—7月份降水量和月均温的影响较大，植被的长势可能受到了前期气象条件的滞后效应影响。地形特征对承德全域植被覆盖状况也有一定的影响，总体来看承德市地势低平地区的NDVI值相对较低。研究结果可为承德市加强重要区域生态保护、优化国土空间开发格局和科学制定生态修复措施提供参考。 相似文献
6.
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
7.
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
8.
Identifying spatial patterns of synchronization between NDVI and climatic determinants using joint recurrence plots 总被引：1，自引：0，他引：1
Shuangcheng Li Zhiqiang Zhao Yang Wang Yanglin Wang 《Environmental Earth Sciences》2011,64(3):851-859
Ten-day series of the Normalized Difference Vegetation Index (NDVI) derived from multi-temporal satellite imagery (1998–2008)
was employed as a surrogate for the surface vegetation cover to investigate synchronization of the climatic determinants and
its spatial patterns in China. The results, both of the spatiotemporal patterns of joint probability of recurrence (JPR) index
and lag time of maximal JPR, clearly suggest that the synchronous relationships of NDVI–climate are site specific and spatially
heterogeneous. Higher JPR values of NDVI–temperature are found in Northern China, indicating stronger synchronization in these
areas, while higher JPR values of NDVI–precipitation are found in semi-arid and semi-humid regions, which suggest that the
moisture factor has a significant influence on NDVI in these areas. Whether lagged or advanced relationship, the phase difference
of NDVI–temperature is smaller in Southern China, while is bigger in Northern China. In contrast, the phase difference of
NDVI–precipitation is smaller in the semi-arid and sub-humid areas, which means that precipitation has a significant and immediate
influence on vegetation in these areas. Overall, the JPR values for NDVI–temperature are higher than those for NDVI–precipitation,
suggest that the synchronization between NDVI and temperature is stronger than that between NDVI and precipitation in most
areas of China. The results indicate that joint recurrence quantification analysis is a good candidate method for identifying
the synchronization between NDVI and climatic determinants. 相似文献
9.
10.
青藏高原高寒草地植被指数变化与地表温度的相互关系 总被引：3，自引：1，他引：2
为了解脆弱的高原生态环境对升温过程的响应, 利用1982-2006年国家标准地面气象站地表温度和GIMMS-NDVI数据集, 探讨了青藏高原高寒草地植被指数和地表温度的变化特征及其相互关系. 结果表明:1982-2006年, 高寒草地NDVI、地表温度整体均呈现增加趋势, 年均NDVI、生长季NDVI、年最大NDVI(NDVImax)与年均地表温度、生长季地表温度的上升趋势分别为0.007 (10a)-1、0.011 (10a)-1、0.007 (10a)-1与0.60 ℃·(10a)-1、0.43 ℃·(10a)-1; NDVImax与地表温度显著相关的地区达70.49%. 但是高原地形、气候、水文环境的空间差异性导致高寒草地NDVI与地表温度的相关关系十分复杂. NDVImax与年均地表温度的相关性最为显著; 在返青期和枯萎期, NDVI与地表温度均为显著正相关. 不同的植被覆盖条件下, NDVI对地表温度的响应不同:植被覆盖差以及退化严重的地区, NDVImax与地表温度呈负相关性; 反之, NDVImax与地表温度主要表现为正相关. 相似文献
11.
Assessing vegetation dynamics and their relationships with climatic variability in Heilongjiang province, northeast China 总被引：2，自引：1，他引：1
Wenbin Liu Tijiu Cai Cunyong Ju Guobin Fu Yuefeng Yao Xueqing Cui 《Environmental Earth Sciences》2011,64(8):2013-2024
In this study, the vegetation dynamics in Heilongjiang province and their relationships with climate variability were assessed
using normalized difference vegetation index (NDVI) and meteorological datasets from 1981 to 2003. The conclusions from our
results are as follows: (1) After 1981, vegetation cover, as indicated by the NDVI, exhibited an insignificant increasing
tendency. However, the inter-annual variations of the NDVI showed apparent spatial differentiations. (2) The inter-annual
changes of the NDVI were different from season to season. The spring and autumn NDVI values increased, while the summer and
winter NDVI decreased. (3) The annual NDVI was significantly correlated with precipitation. Thus, as compared to temperature,
precipitation was the dominant climatic factor affecting the vegetation dynamics in Heilongjiang province. (4) The trend in
the NDVI showed a marked homogeneity corresponding to regional and seasonal variations in climate. Additionally, land use
changes also play an important role in influencing the NDVI trends over some regions. All of these findings will enrich our
knowledge of the natural forces that impact the stability of boreal ecosystems and provide a scientific basis for the environmental
management in Heilongjiang province in response to climate change and human activities. 相似文献
12.
格尔木河流域植被指数时空分布及其影响因素研究 总被引：2，自引：0，他引：2
格尔木河流域气候干旱少雨,生态环境较脆弱,植被动态对其生态环境保护具有重要意义。基于连续序列的MODIS NDVI数据,分析了格尔木河流域植被指数时空分布及其影响因素。结果表明:研究区NDVI平均值总体较小,主要在0.10～0.12间波动,但呈增大趋势。区内植被改善区分布在格尔木市东、西两侧,基本不变区为荒漠地区,植被退化区分布在北部盐湖区。区内裸土的面积逐渐减小,低覆盖率和高覆盖率植被的面积逐渐增加。研究区植被生长与气象、土壤水分和地下水位埋深都有关系。气温与植被指数相关关系较好,相关系数为0.822,而降水对植被的生长也有一定的作用。植被指数与表观热惯量是正相关关系,相关系数为0.979。区内植被的地下水位埋深范围为0～12 m,在水位埋深约为6.5 m的地方,植被长势最好。 相似文献
13.
为了研究中蒙俄经济走廊沿海与内陆地区归一化植被指数（NDVI）的分布特征,利用MOD13Q1 NDVI数据集、MERRA2气象再分析数据和AVHRR土地覆盖数据,以中蒙俄经济走廊研究区内2种代表性植被（林地和树木茂盛的草地）为例,采用回归分析法和相关性分析法研究了近年来研究区NDVI在不同纬度、距海岸线不同距离及不同时间的变化特征,并分析了气温与降水对NDVI的影响。结果表明：2015—2019年内5月下旬—9月,沿海地区植被生长状态基本优于内陆地区,从距离海岸线500 km左右开始,NDVI明显下降;沿海地区（0~500 km）与内陆地区NDVI在时间变化上也略有不同,沿海地区2种代表性植被的NDVI时序变化模型拟合效果较好。受沿海与内陆地区降水、气温差异影响,在植被生长顶峰期（0719—0723）,随着纬度上升,沿海与内陆地区NDVI差异逐渐减小：沿海地区NDVI在上升期比内陆地区约提前1个月进入饱和,下降期滞后约1个月;低纬度地区2种植被对降水量更为敏感,相关系数最高为0.393（显著性水平P<0.01）,而高纬度地区两种植被对气温更为敏感,相关系数最高为0.534（P<0.01）。 相似文献
14.
Assessing vegetation dynamics impacted by climate change in the southwestern karst region of China with AVHRR NDVI and AVHRR NPP time-series 总被引：6，自引：0，他引：6
The relationship between climate change and vegetation dynamics in the southwestern karst region of China has been identified
by recent studies. Based on previous researches and AVHRR (Advanced Very High Resolution Radiometer) GIMMS (Global Inventory
Monitoring and Modeling Studies) NDVI (Normalized Difference Vegetation Index) (1982–2003) and AVHRR GloPEM (Global Production
Efficiency Model) NPP (Net Primary Production) (1981–2000) datasets, vegetation dynamics impacted by climate change in the
southwestern karst region of China were assessed. The results show that: (1) since the early 1980s, both vegetation cover
density and net primary production have insignificant ascending tendencies. However, the inter-annual variation rates of vegetation
indexes have apparent spatial differentiations; (2) the correlation coefficients between the inter-annual variations of vegetation
indexes and the inter-annual variations of climate factors vary geographically; (3) as indicated by NDVI and NPP, various
vegetation types have different responses to climate change, and the annual mean temperature variation has more significant
impact on vegetation dynamics than the annual precipitation variation in the study area; (4) distribution laws of correlation
coefficients between the inter-annual variations of vegetation indexes and the inter-annual variations of climate factors
in different climate conditions are apparent. All these findings will enrich our knowledge of the natural forces which impact
the stability of the karst ecosystems and provide scientific basis for the management of the karst ecosystems. 相似文献
15.
Application of meteorological and vegetation indices for evaluation of drought impact: a case study for Rajasthan, India 总被引：3，自引：1，他引：2
Drought is a serious climatic condition that affects nearly all climatic zones worldwide, with semi-arid regions being especially
susceptible to drought conditions because of their low annual precipitation and sensitivity to climate changes. Drought indices
such as the standardized precipitation index (SPI) using meteorological data and vegetation indices from satellite data were
developed for quantifying drought conditions. Remote sensing of semi-arid vegetation can provide vegetation indices which
can be used to link drought conditions when correlated with various meteorological data based drought indices. The present
study was carried out for drought monitoring for three districts namely Bhilwara, Kota and Udaipur of Rajasthan state in India
using SPI, normalized difference vegetation index (NDVI), water supply vegetation index (WSVI) and vegetation condition index
(VCI) derived from the Advanced Very High resolution Radiometer (AVHRR). The SPI was computed at different time scales of
1, 2, 3, 6, 9 and 12 months using monthly rainfall data. The NDVI and WSVI were correlated to the SPI and it was observed
that for the three stations, the correlation coefficient was high for different time scales. Bhilwara district having the
best correlation for the 9-month time scale shows late response while Kota district having the best correlation for 1-month
shows fast response. On the basis of the SPI analysis, it was found that the area was worst affected by drought in the year
2002. This was validated on the basis of NDVI, WSVI and VCI. The study clearly shows that integrated analysis of ground measured
data and satellite data has a great potential in drought monitoring. 相似文献
16.
For the last three decades, Northern China has been considered as one of the most sensitive areas regarding global environmental change. The integration of AVHRR GIMMS and MODIS NDVI data (1982–2011), of which for the overlapping period of 2000–2006 show good consistency, were used for characterizing land condition variability. The trends of standardized annually ΣNDVI, temperature, precipitation and PDSI were obtained using a linear regression model. The results showed that Northern China has a general increase in greenness for the period 1982–2011 (a = 0.05). Also, annually ΣNDVI is significantly correlated with temperature and precipitation data at the regional scale (p < 0.05), implying that temperature and precipitation are the dominant limiting factors for vegetation growth. Since the greening is not uniform, factors other than temperature and precipitation may contribute to greening in some areas, while the grassland and cropland ecosystem are becoming increasingly vulnerable to drought. The results of trend analysis indicate that greenness seems to be evident in most of the study areas. 相似文献
17.
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
18.
黑河流域天然植被的面积变化研究 总被引：8，自引：1，他引：8
植被覆盖面积的大小是反映区域性生态环境状况的重要指标之一,多年植被覆盖面积的变化则直观反映了植被生态环境随时间的变化规律。在前人研究成果的基础上,采用定量遥感技术,应用美国国家航天航空局最新的全球植被指数变化研究数据(GIMMS)作为数据源,对黑河流域1989-2002年间的植被面积变化规律进行了研究。考虑到实际的植被面积难以确定,因此采用等效面积法确定植被覆盖面积,通过统计遥感图像上植被指数(NDVI)值大于0.3的像素点值,以像素点值代表植被的面积,研究黑河流域14 a的天然植被面积变化规律。研究结果证明,黑河流域的天然植被在以每年约3%的速度减少。 相似文献
19.
中国东北样带NDVI的季节变化及其与气候因子的关系 总被引：20，自引：0，他引：20
NDVI是研究大尺度生态学问题一个非常有用的指数,它可以为估价全球植被动态模型提供足够的信息.中国东北样带是全球变化研究中首选样带之一,本文分析了分辨率为1km×1km的NDVI年内季节变化的两个特征值:年均NDVI(NDVI-I)和NDVI年内极差(NDVI-MM)在样带内5种不同植被类型间的变化及其与年平均气温和降水量之间的相关关系.结果表明,NDVI具有明显的季节变化格局,NDVI-I和NDVI-MM由东到西均呈下降趋势,NDVI-I与降水量具有显著的线性回归关系,降水量能够解释NDVI-I和NDVI-MM空间变异的绝大部分.这一结果说明NDVI反映了植被沿环境梯度的时空变化格局,可用于监测样带植被对气候变化的响应. 相似文献
20.
Iraq, the land of two rivers, has a history that extends back millennia and is the subject of much archaeological research. However, little environmental research has been carried out, and as such relatively little is known about the interaction between Iraq’s vegetation and climate. This research serves to fill this knowledge gap by investigating the relationship between the Normalized Difference Vegetation Index (NDVI) and two climatic factors (precipitation and air temperature) over the last decade. The precipitation and air temperature datasets are from the Water and Global Change Forcing Data ERA-Interim (WFDEI), and the NDVI dataset was extracted from the Moderate Resolution Imaging Spectroradiometer (MODIS) at 250 m spatial resolution and 16 day temporal resolution. Three different climatic regions in Iraq, Sulaymaniyah, Wasit, and Basrah, were selected for the period of 2001–2015. This is the first study to compare these regions in Iraq, and one of only a few investigating vegetation’s relationship with multiple climatic factors, including precipitation and air temperature, particularly in a semi-arid region. The interannual, intra-annual and seasonal variability for each region is analysed to compare the different responses of vegetation growth to climatic factors. Correlations between NDVI and climatic factors are also included. Plotting annual cycles of NDVI and precipitation reveals a coherent onset, fluctuation (peak and decline), with a time lag of 4 months for Sulaymaniyah and Wasit (while for the Basrah region, high temperatures and a short rainy season was observed). The correlation coefficients between NDVI and precipitation are relatively high, especially in Sulaymaniyah, and the largest positive correlation was (0.8635) with a time lag of 4 months. The phenological transition points range between 3 and 4 month time lag; this corresponds to the duration of maturity of the vegetation. However, when correlated with air temperature, NDVI experiences an inverse relationship, although not as strong as that of NDVI and precipitation; the highest negative correlation was observed in Wasit with a time lag of 2 months (? 0.7562). The results showed that there is a similarity between temporal patterns of NDVI and precipitation. This similarity is stronger than that of NDVI and air temperature, so it can be concluded that NDVI is a sensitive indicator of the inter-annual variability of precipitation and that precipitation constitutes the primary factor in germination while the air temperature acts with a lesser effect. 相似文献