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1.
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
2.
《地学前缘(英文版)》2022,13(2):101312
Drought is a natural phenomenon posing severe implications for soil, groundwater and agricultural yield. It has been recognized as one of the most pervasive global change drivers to affect the soil. Soil being a weakly renewable resource takes a long time to form, but it takes no time to degrade. However, the response of soil to drought conditions as soil loss is not manifested in the existing literature. Thus, this study makes a concerted effort to analyze the relationship between drought conditions and soil erosion in the middle sub-basin of the Godavari River in India. MODIS remote sensing data was utilized for driving drought indices during 2000–2019. Firstly, we constricted Temperature condition index (TCI) and Vegetation Condition Index (VCI) from Land Surface Temperature (LST) and Enhanced Vegetation Index (EVI) derived from MODIS data. TCI and VCI were then integrated to determine the Vegetation Health Index (VHI). Revised Universal Soil Loss Equation (RUSLE) was utilized for estimating soil loss. The relationship between drought condition and vegetation was ascertained using the Pearson correlation. Most of the northern and southern watersheds experienced severe drought condition in the sub-basin during 2000–2019. The mean frequency of the drought occurrence was 7.95 months. The average soil erosion in the sub-basin was estimated to be 9.88 t ha?1 year?1. A positive relationship was observed between drought indices and soil erosion values (r value being 0.35). However, wide variations were observed in the distribution of spatial correlation. Among various factors, the slope length and steepness were found to be the main drivers of soil erosion in the sub-basin. Thus, the study calls for policy measures to lessen the impact of drought and soil erosion. 相似文献
3.
Drought is one of the most detrimental natural disasters. Studying the changing characteristics of drought is obviously of great importance to achieve the sustainable use of water resources at river basin scales. In this paper, the satellite-based Vegetation Condition Index (VCI) and Vegetation Health Index (VH) were firstly calculated by using NDVI and brightness of the Global Vegetation Index dataset derived from Advance Very High Resolution Radiometer for China in growing seasons over 1982–2005. Then, the long-term VCI and VH data were employed to study the variation of droughts in the ten basins covering the whole country. The linear trend of each pixel showed that most parts of China were getting wetter in growing seasons, and the drought areas defined by the number of drought pixels have decreased in most basins. The increasing trend of basin averaged values of VCI and VH also indicates the whole country was generally getting wetter. At last, to better understand the two remote sensing drought indices, the response of the growing-season VCI and VH was compared to that of the Palmer Drought Severity Index and 6-month Standard Precipitation Index. Significant spatial variability of the relationship between the VCI, VH, and the station-based meteorological drought indices was shown, and some more closely related areas were found. The study will be useful for water resources management for each basin in the future. 相似文献
4.
This paper has developed a general Ts-NDVI triangle space with vegetation index time-series data from AVHRR and MODIS to monitor soil moisture in the Mongolian Plateau during 1981–2012, and studied the spatio-temporal variations of drought based on the temperature vegetation dryness index (TVDI). The results indicated that (1) the developed general Ts-NDVI space extracted from the AVHRR and MODIS remote sensing data would be an effective method to monitor regional drought, moreover, it would be more meaningful if the single time Ts-NDVI space showed an unstable condition; (2) the inverted TVDI was expected to reflect the water deficit in the study area. It was found to be in close negative agreement with precipitation and 10 cm soil moisture; (3) in the Mongolian Plateau, TVDI presented a zonal distribution with changes in land use/land cover types, vegetation cover and latitude. The soil moisture is low in bare land, construction land and grassland. During 1981–2012, drought was widely spread throughout the plateau, and aridification was obvious in the study period. Vegetation degradation, overgrazing, and climate warming could be considered as the main reasons. 相似文献
5.
Identifying effective vegetation biophysical and spectral parameters for investigating light to moderate grazing effects on grasslands improves management practices on grasslands. Using mixed grasslands as a case study, this paper compares responses of vegetation biophysical properties and spectral parameters derived from satellite images to grazing intensity, and identifies the suitable biophysical and spectral parameters to detect grazing effects in these areas. Biophysical properties including cover, canopy height and Leaf area index (LAI) were measured in three sites with different grazing managements and one benchmark site in 2008 and 2009 in Grasslands PlaceTypeNational Park and surrounding provincial pastures, Canada. Thirteen vegetation spectral indices, calculated by statistically combining different spectral information, were evaluated. The results indicate that canopy height and the ratio of photosynthetically active vegetation cover to non-photosynthetically active vegetation cover (PV/NPV) showed significant differences between ungrazed and grazed sites. All spectral vegetation indices except the canopy index (CI) show significant differences between grazing treatments. Red-Near infrared (Red-NIR) based vegetation indices, such as Modified Triangular Vegetation Index 1 (MTVI1), Soil-adjusted Vegetation Index (SAVI), are significantly correlated to the PV/NPV. Green/Mid-infrared (Green/MIR) related vegetation indices, i.e. Plant Senescence Reflectance Index (PRSI) and Normalized Canopy Index (NCI), show significant correlation with canopy height. Models based on a linear combination of MTVI1 and SAVI were developed for PV/NPV and PRSI and NCI for canopy height. Models that simulated PV/NPV and canopy height show significant correlations with grazing intensity, suggesting the feasibility of remote sensing to quantify light to moderate grazing effects in mixed grasslands. 相似文献
6.
7.
From early November 2008 to February 2009, lack of rainfall led to severe drought in northern China. More than 9.3 million ha of wheat in six major crop production provinces, including Henan, Anhui, Shandong, Shanxi, Gansu, and Shaanxi, were hit by drought. Supported by Chinese HJ-1 satellite images together with NASA Moderate Resolution Imaging Spectroradiometer (MODIS) data, dynamic monitoring of the drought was conducted. HJ-1 CCD data with 30-m resolution were used to identify cropland information. Spatial–temporal variation of drought was detected using Vegetation Index and Water Index time series data derived from MODIS visible, infrared, and short-wave infrared bands. The influences of drought were classified into five levels based on MODIS-derived 8-day composite Anomaly Water Index (AWI) and field survey data. The results indicated that the drought deteriorated beginning in November 2008 and became most serious in late January 2009. HJ-1 data together with MODIS data proved to be valuable data sources for monitoring soil moisture and drought at a both regional and national scale. 相似文献
8.
Hassan Yeganeh Seyed jamale Khajedein Fazel Amiri Abdul Rashid B. Mohamed Shariff 《Arabian Journal of Geosciences》2014,7(1):287-298
The aim of the present research is to monitor changes in herbage production during the grazing season in the Semirom and Brojen regions, Iran, using multitemporal Moderate Resolution Imaging Spectroradiometer (MODIS) data. At first, various preprocessing steps were applied to a topography map. The atmospheric and topographic corrections were applied using subtraction of the dark object method and the Lambert method. Image processing, including false-color composite, principal component analysis, and vegetation indices were employed to produce land use and pasture production maps. Vegetation sampling was carried out over a period of 4 months during June–September 2008, using a stratified random sampling method. Twenty random sampling points were selected, and herbage production was estimated and verified with the double-checking method. Four MODIS data sets were used in this study. The models for image processing and integrating ground data with satellite images were processed, and the resulting images were categorized into seven classes. Finally, the land covers were verified for accuracy. A postclassification analysis was carried out to verify the seven class change detections. The results confirmed that Normalized Difference Vegetation Index (NDVI) and Soil-Adjusted Vegetation Index (SAVI) maps had a close relationship with the field data. The indices produced with shortwave infrared bands had a close relationship with field data where the ground cover and yields were high. The R 2 value observed was 0.85. The changes in the pasture vegetation were high during the growing season in more than 90 % of the pastures. During the growing season, most changes in the pastures belonged to class 5 and 2 in the NDVI and SAVI index maps, respectively. 相似文献
9.
植被状况指数的改进及在西北干旱监测中的应用 总被引：8，自引：0，他引：8
干旱是全球分布最广、发生频率最高、持续时间最长、影响范围最大、造成的经济损失最为严重的一种自然灾害，干旱也是所有自然灾害中影响因子最为复杂、人类了解最少、监测最为困难的一种自然灾害，干旱监测是世界性的难题。干旱可以发生在任何气候带上，但干旱、半干旱地区是全球干旱灾害发生最频繁的地区。干旱发生特征和规律因地区的不同会有很大的差异，不同地区对干旱监测方法不同。目前，世界各国干旱监测主要利用基于气象、水文、农业和卫星遥感等观测资料建立的各种干旱指数开展，已经有150多种干旱指数。植被状况指数VCI是应用最为广泛的一种卫星监测干旱的指数，研究和业务应用结果表明，VCI对全球各地的干旱均有较好的反映，已经应用在美国国家大气海洋局（NOAA）日常干旱监测业务中，中国国家卫星气象中心干旱卫星遥感监测服务产品也是以VCI为基础。
我国干旱半干旱地区主要分布在新疆、甘肃、青海、陕西、宁夏以及内蒙古自治区的中西部，这里降水少且不稳定，降水变率大，是中国干旱发生频率最高的地区。干旱严重制约着当地经济发展和人类生活质量的提高，使本身非常脆弱的生态环境趋于恶化。为了了解条件植被指数VCI对西北地区不同气候区干旱的监测能力，以上述6省（区）为研究区，利用1982—2003年22年NDVI数据，计算了研究区域22年来逐月的VCI，对比分析了不同气候区VCI与降水距平的关系。结果表明，VCI在空间和时间上较好地反映了西北大部分气候干旱发生、发展和空间分布，是干旱监测的较好指标，但在干旱和极端干旱地区，VCI经常出现异常偏高现象，不能反映干旱气候区常年干旱的基本特点。通过对西北不同生态系统之间NDVI特点和各生态系统间NDVI年变化及其年际变化规律的研究，设计了VCI改进方案，提出了改进的条件植被指数RVCI。通过对22年来逐月RVCI与VCI的对比，RVCI客观地反映了干旱气候区常年干旱特点，较VCI有显著改进。
相似文献
10.
藏西北地区生态环境脆弱,由于地形复杂、气候独特,该区的观测资料非常缺乏。利用遥感技术开展藏西北地区的干旱监测,能获取在空间上连续变化的地表干旱情况,对于指导该区农牧业生产具有重要的意义。基于FY-3A/VIRR的一级数据和标准旬产品（地表温度、植被指数）,采用温度植被干旱指数（TVDI）进行藏西北地区的干旱监测研究,并将监测结果分别与基于EOS/MODIS数据监测的结果、同期的野外实测土壤水分数据以及气象站点的降水量数据进行了对比分析。结果表明：利用FY-3A/VIRR数据的TVDI遥感监测结果与实测土壤水分、气象站累计降水量数据均呈显著的负相关关系,通过了0.01水平的显著性检验;利用FY-3A/VIRR数据与EOS/MODIS数据估算的TVDI干旱等级空间分布特征基本一致,FY-3A/VIRR数据可以代替EOS/MODIS数据在藏西北地区开展干旱遥感监测,可为指导藏西北地区农牧业生产提供数据支持。 相似文献
11.
使用1982-2006年GIMMS AVHRR NDVI数据集与同期的CI、K、Pa、SPI、Z、PDSI等干旱指数做了对比分析, 讨论了河南省植被状态指数VCI对气象干旱的滞后效应及干旱监测能力. 结果表明: VCI指数与气象干旱指数的相关性受不同下垫面的影响较大, 农地的VCI与气象干旱指数相关性要明显高于林地, 农地VCI与气象干旱指数呈现正相关关系. 在河南省不同的作物生长阶段, VCI对气象干旱有着不同的滞后效应, 其中, 3-5月份冬小麦生长期VCI对气象条件的反应滞后1~3个月, 7、9月份夏玉米生长期VCI对气象条件的反应滞后1月. 总体上看, 结合前期的气象数据, VCI对河南省气象干旱有一定的指示作用和监测能力. 相似文献
12.
植被在陆面参数化方案（Land Surface Parameterizations, LSPs）中的描述经历着从定性描述向定量描述发展的过程。这一方面是由于陆面过程研究的深入,另一方面则得益于地表植被信息获取方式的进步,尤其是卫星遥感技术的发展。对三代LSPs中的植被描述做了简要概述,并介绍了卫星遥感在植被参数反演上的发展和应用情况。其中包括：①定性描述,主要指地表覆盖类型的描述方式;②部分参数定量描述,指SiB2等模式中对LAI等时空变化较大的少数参数由卫星资料直接反演的赋值方式;③植被特征连续分布（VCF）定量描述,一种完全定量的描述方式。 相似文献
13.
植被盖度作为地表特征指数之一,其发育和分布特征受控于生态地质环境,而地质灾害又是生态地质环境不良作用的表现方式之一,二者存在一定联系。以地质灾害发育且危害严重的丹巴县为例,采用1999年和2006年二期卫星遥感数据,提取这二个时相的植被盖度图,以及1999年～2006年植被盖度变化图,采用地理信息系统技术,将地质灾害与二期的植被覆盖图进行叠加和统计分析。其结果表明,地质灾害主要分布在海拔较低,人类工程活动强烈的低植被覆盖和较低植被覆盖区域,且地质灾害在植被覆盖度减少的区域较之植被盖度不变和增加的区域,更加容易突发,研究结果与区内其它地质灾害工作成果吻合。 相似文献
14.
基于多尺度遥感数据估算地表通量的方法及其验证分析 总被引：2，自引：0，他引：2
地表水热通量(显热通量、潜热通量)的遥感估算在全球气候变化、水资源、生态环境等研究领域具有重要的应用价值.MODIS数据的空间分辨率较低(热红外波段星下点为1 km),而地球表面的几何物理属性又具有高度非均匀性,因而在实际应用中面临较严重的尺度问题.探讨了多源卫星数据(中高分辨率Landsat TM与中低分辨率MODIS)相结合佑算像元通量的2种方法,分别利用高分辫率的地表分类及植被指数信息在混合像元内部进行亚像元处理,以提高非均匀地表混合像元的通量估算精度.研究数据来自于2008年黑河流域综合实验获取的遥感数据和辅助数据,验证数据来自于实验期间获取的不同下垫面的地表通量数据,包括涡度相关(EC)数据,以及大孔径闪烁仪(LAS)数据.计算结果表明,2种方法皆可在下垫面不均匀或者地表类型较复杂的情况下得到比较明显的纠正效果,纠正后的通量与观测更加接近.相比之下,利用植被指数分解温度的方法适用性更广,纠正效果更好.在地面验证中,对比分析了EC和LAS数据在TM尺度和MO-DIS尺度通量验证的适用性.LAS数据测量尺度与MODIS卫星像元尺度相匹配,可以直接验证MODIS通量计算结果,EC数据虽然可以直接验证TM计算的通量,但与MODIS数据对比,还需要进行尺度转换,即先用EC验证TM通量,然后将TM通量降尺度,与MODIS进行对比.最后对利用LAS验证通量的不确定性进行了分析,发现图像中LAS测点的几何定位误差以及LAS测量路径中像元的选取都对验证结果有一定影响. 相似文献
15.
Droughts are hindrances to economic and social developments in many parts of the world, especially in developing nations like Kenya. In North Eastern Kenya (NEK), drought is very prevalent. The communities in the region are mainly dependent on animal farming, and drought occurrence leads to great socioeconomic setback. Drought indices used in most studies consider rainfall as the only parameter for assessing drought occurrences. This study analyzes drought in NEK using the Standardized Precipitation Index (SPI) and the Combined Drought Index (CDI) using rainfall and temperature values and Normalized Difference Vegetation Index values for the period 1980–2010. The results of the two indices show significant correlation. However, CDI is preferred in the analysis of the drought compared to the SPI as it gives drought in more detail, showing extreme, severe, moderate and mild. The study recommends the use of the two methods independently since they give similar results and further recommends trial in other parts of the country affected by drought.
相似文献16.
Vegetation is a natural source of Volatile Organic Compounds (VOC) that plays an important role in atmospheric chemistry. The main objective of the current study is to implement a model to quantify process-based VOC emissions from plants that focuses on the relationship between the sensitivity of VOC emission estimates to spatial resolution data, based on scientific knowledge and vegetation dynamics derived from satellite observations. The Normalized Difference Vegetation Index (NDVI) and Leaf Area Index (LAI) were elected to examine this issue using different resolutions of satellite-derived products: 22m from the DEIMOS-1 satellite, and 250m and 1000m provided by MODIS. The study is focused on an area of 80×80km2 in Portugal for 2011. Detailed land cover and meteorological data are also included in the emission quantification algorithm. The primary outcomes were determined using a multi-scale analysis showing spatial and temporal variations in the vegetation parameters and modeling results. The results confirm that the emissions model is highly sensitive to the spatial resolution of the satellite-derived data, resulting in about a 30% difference in total isoprene emissions for the study area. 相似文献
17.
植被覆盖是评价区域生态环境状态的主要影响因子.基于景观生态学的分析方法,以2006-2015年的MOD13Q1遥感数据为基础,获取植被覆盖指数,对山西省晋城市植被覆盖时空变化进行研究.结果表明:研究区植被覆盖呈现增加趋势,主要增加的类型为高植被覆盖.植被覆盖指数分布与高程和坡度正相关,即高程越高、坡度越大的地区植被覆盖指数越高.在景观尺度上,植被覆盖的类型呈现出一种集中趋势,即景观内部异质性和多样性降低,高植被覆盖斑块对景观的支配程度加强且逐渐处于优势地位.在斑块类型尺度上,以高植被覆盖为主,且斑块所占比例呈增加趋势.此外高植被覆盖景观破碎程度减小,复杂度降低,形状逐渐规则. 相似文献
18.
Yajie Zhang Yao Li Jing Ge Gaopeng Li Zhisheng Yu Haishan Niu 《Environmental Earth Sciences》2018,77(12):462
Drought monitoring is a key topic in environmental monitoring and assessment although there is still a need to determine the correlation between drought monitoring indices and remote sensing products. We analyzed the correlation between the self-calibrating Palmer Drought Severity Index (sc_PDSI), the Standardized Precipitation Index and the Standardized Precipitation Evapotranspiration Index (SPEI) and terrestrial water storage monitored through the Gravity Recovery and Climate Experiment (GRACE) on a monthly timescale from 2002 to 2015 in China. As a consequence of anomalies in the soil water budget, the highly significant correlation between the sc_PDSI and the GRACE satellite-observed terrestrial water storage suggested that these two datasets are the most suitable for use in monitoring droughts. In comparing the three drought indices, the sc_PDSI was introduced as a means of drought monitoring in the Yangtze, Pearl, Huaihe, Southeast and Songhua River Basins, whereas the SPEI was found to be more applicable to other major river basins, such as the Inland River Basin. These diverse spatial behaviors are caused by the differences between the hydrological droughts characterized by these three drought indices. 相似文献
19.
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
20.
Application of hyperspectral remote sensing for environment monitoring in mining areas 总被引：2，自引：1，他引：1
Environmental problems caused by extraction of minerals have long been a focus on environmental earth sciences. Vegetation
growing conditions are an indirect indicator of the environmental problem in mining areas. A growing number of studies in
recent years made substantial efforts to better utilize remote sensing for dynamic monitoring of vegetation growth conditions
and the environment in mining areas. In this article, airborne and satellite hypersectral remote sensing data—HyMap and Hyperion
images are used in the Mount Lyell mining area in Australia and Dexing copper mining area in China, respectively. Based on
the analyses of biogeochemical effect of dominant minerals, the vegetation spectrum and vegetation indices, two hyperspectral
indices: vegetation inferiority index (VII) and water absorption disrelated index (WDI) are employed to monitor the environment
in the mining area. Experimental results indicate that VII can effectively distinguish the stressed and unstressed vegetation
growth situation in mining areas. The sensitivity of VII to the vegetation growth condition is shown to be superior to the
traditional vegetation index—NDVI. The other index, WDI, is capable of informing whether the target vegetation is affected
by a certain mineral. It is an important index that can effectively distinguish the hematite areas that are covered with sparse
vegetation. The successful applications of VII and WDI show that hyperspectral remote sensing provides a good method to effectively
monitor and evaluate the vegetation and its ecological environment in mining areas. 相似文献