Annual Enhanced Vegetation Index Research Articles

Associations between greenness and kidney disease in Massachusetts: The US Medicare longitudinal cohort study

BackgroundRecent studies have identified the association of environmental stressors with reduced kidney function and the development of kidney disease. While residential greenness has been linked to many health benefits, the association between residential greenness and the development of kidney disease is not clear. We aimed to investigate the association between residential greenness and the development of kidney disease. MethodsWe performed a longitudinal population-based cohort study including all fee-for-service Medicare Part A beneficiaries (aged 65 years or older) in Massachusetts (2000–2016). We assessed greenness with the annual average Enhanced Vegetation Index (EVI) based on residential ZIP codes of beneficiaries. We applied Cox-equivalent Poisson models to estimate the association between EVI and first hospital admission for total kidney disease, chronic kidney disease (CKD), and acute kidney injury (AKI), separately. ResultsData for 1,462,949 beneficiaries who resided in a total of 644 ZIP codes were analyzed. The total person-years of follow-up for total kidney disease, CKD, and AKI were 9.8, 10.9, and 10.8 million person-years, respectively. For a 0.1 increase in annual EVI, the hazard ratios (HRs) were 0.95 (95% CI: 0.93 to 0.97) for the first hospital admission for total kidney disease, and the association was more prominent for AKI (HR: 0.94 with 95% CI: 0.92 to 0.97) than CKD (HR: 0.98 with 95% CI: 0.95–1.01]). The estimated effects of EVI on kidney disease were generally more evident in White beneficiaries and those residing in metropolitan areas compared to the overall population. ConclusionsThis study found that higher levels of annual residential greenness were associated with a lower risk of the first hospital admission for kidney diseases. Results are consistent with the hypothesis that higher residential greenness benefits kidney patients.

Legume Overseeding along with P Fertilization Increase Forage Production of Temperate Natural Grasslands

Legume overseeding along with P fertilization is a common practice used in natural temperate and subtropical grasslands to increase forage production. This practice has been evaluated at experimental plots but not at the paddocks level of commercial farms. The latter are realistic evaluation units to generate knowledge for livestock management. In this study, the enhanced vegetation index (EVI), a proxy of forage production, was used to evaluate the effect of this practice on grazed paddocks in Uruguay. Twenty paired paddocks under similar grazing conditions were selected with natural grassland (NG) and natural grassland with legume overseeding and P fertilization (NG-LP). Paired paddocks were compared in terms of EVI mean and its temporal variability. After nine years of the intensification practice, mean annual EVI of NG-LP was 4% higher than that of NG, while the mean winter–spring EVI of NG-LP was 7.5% higher. EVI intra- and inter-annual variability of NG-LP was 8–11% higher than that of NG. Additionally, forage production was estimated using a radiative transfer model. Differences between NG-LP and NG were amplified six to seven times. Legume overseeding along with P fertilization increased forage production in pastoral livestock paddocks, particularly in the period of forage deficit, while it also increased intra and inter-annual variability of forage production.

Remotely sensed trends in vegetation productivity and phenology during population decline of the Bathurst caribou (Rangifer tarandus groenlandicus) herd

The Bathurst caribou (Rangifer tarandus groenlandicus (Borowski, 1780)) herd declined from ∼349 000 animals in 1996 to ∼8200 in 2018. Climate-driven changes to tundra and boreal vegetation is one hypothesis for the decline. We modelled and mapped annual productivity and phenology across the herd’s range using enhanced vegetation index (EVI) data derived from a Moderate Resolution Imaging Spectroradiometer (MODIS) time series spanning 2000–2017. Maximum annual EVI, growing season length, and time-integrated EVI increased significantly on 16%, 18%, and 49% of the core annual range, respectively. Trends toward longer growing seasons were driven entirely by earlier spring green-up and, along with time-integrated EVI, were most prevalent in tundra regions. Trends in forested regions were overwhelmingly related to the influence of forest fires, which burned more than half of the range below the forest–tundra ecotone since 1965. These trends suggest that climate-driven changes in production and phenology have occurred in the tundra and forest–tundra portions of the range and could have contributed to the recent herd decline. However, the trends may also be a result of herd decline itself, given the loss of this large herbivore from the landscape. Elucidating cause and effect will require comprehensive analysis of interactions between climatic variables, herd dynamics, and vegetation change, complemented by targeted field investigations.

New assessment for residential greenness and the association with cortical thickness in cognitively healthy adults.

Recent evidence suggests that neurological health could be improved with the intervention of local green space. A few studies adopted cortical thickness, as an effective biomarker for neurodegenerative disorder, to investigate the association with residential greenness. However, they relied on limited data sources, definitions or applications to assess residential greenness. Our cross-sectional study assessed individual residential greenness using an alternative measure, which provides a more realistic definition of local impact and application based on the type of area, and investigated the association with cortical thickness. The study population included 2542 subjects who participated in the medical check-up program at the Health Promotion Center of the Samsung Medical Center in Seoul, Korea, from 2008 to 2014. The cortical thickness was calculated by each of the four and global lobes from brain MRI. For greenness, we used the enhanced vegetation index (EVI) that detects canopy structural variation by adjusting background noise based on satellite imagery data. To assess individual exposure to residential greenness, we computed the maximum annual EVI before the date of a medical check-up and averaged it within 750m from subjects' homes to represent an average walking distance. Finally, we assessed the association with cortical thickness by urban and non-urban populations using multiple linear regression adjusting for individual characteristics. The average global cortical thickness and EVI were 3.05mm (standard deviation=0.1mm) and 0.31 (0.1), respectively. An interquartile range increase in EVI was associated with 11μm (95% confidence interval=3-20) and 9μm (1-16) increases in cortical thickness of the parietal and occipital regions among the urban population. We did not find associations in non-urban subjects. Our findings confirm the association between residential greenness and neurological health using alternative exposure assessments, indicating that high exposure to residential greenness can prevent neurological disorders.

2001-2018年中国-老挝交通走廊核心区植被稳定性对极端干旱的响应

中国-老挝交通走廊核心区干旱事件的频繁发生威胁着该区域生态系统的稳定性。基于Palmer干旱指数（PDSI）和增强型植被指数（EVI）数据量化了中老交通走廊核心区不同植被类型的稳定性（年均EVI与其标准差之比）及其对干旱的抵抗力（干旱期间植被结构和功能保持其原始水平的能力）和恢复力（植被恢复到干旱前水平的速度）。结果表明：（1）2001-2018年间，中老交通走廊核心区共发生5次极端干旱事件，出现极端干旱的年份有2005年、2010年、2015年、2016年和2017年，以上年份极端干旱面积占总面积的比例分别为13.37%、47.46%、10.41%、12.00%和3.05%；（2）不同植被类型对极端干旱的响应不同，中老交通走廊核心区内常绿阔叶林的稳定性显著高于其他植被类型，和其他植被类型相比，常绿阔叶林虽然暴露在干旱环境中的时间更长，但其具有更高的稳定性，在维持中老交通走廊核心区的生态系统稳定性上发挥着重要作用；（3）常绿阔叶林和木本稀树草原对极端干旱的抵抗力和恢复力显著高于混交林、草地和农田，研究区内各植被类型对极端干旱的抵抗力与温度和降水呈显著正相关关系。;The core area of China-Laos transportation corridors have been frequently affected by drought events, which threatened the stability of terrestrial ecosystem functioning. Based on the Palmer Drought Severity Index (PDSI) data and enhanced vegetation index (EVI) products, we quantified the temporal stability (ratio of mean annual EVI to its SD), resistance (ability to maintain its original levels during droughts), and resilience (rate of EVI recovering to pre-drought levels) in the core area of China-Laos transportation corridors. The results showed that:(1) there were 5 extreme drought events in the core area of China-Laos transportation corridors from 2001 to 2018, appearing in 2005, 2010, 2015, 2016 and 2017. The area of extreme drought accounted for 13.37%, 47.46%, 10.41%, 12.00% and 3.05%, respectively. (2) Different vegetation types had different responses to droughts. The temporal stability of evergreen broadleaf forests was significantly higher than that of other vegetation types. Evergreen broadleaf forests had higher stability than other vegetation types despite the greater drought exposure, which played an important role in maintaining the ecosystem stability of the corridor core area. (3) The evergreen broadleaf forests and savannas illustrated significantly higher resistance and resilience of EVI than other vegetation types. The resistance of various vegetation types to extreme drought in the study area was positively associated with temperature and precipitation.

High ecosystem stability of evergreen broadleaf forests under severe droughts.

Global increase in drought occurrences threatens the stability of terrestrial ecosystem functioning. Evergreen broadleaf forests (EBFs) keep leaves throughout the year, and therefore could experience higher drought risks than other biomes. However, the recent temporal variability of global vegetation productivity or land carbon sink is mainly driven by non-evergreen ecosystems, such as semiarid grasslands, croplands, and boreal forests. Thus, we hypothesize that EBFs have higher stability than other biomes under the increasingly extreme droughts. Here we use long-term Standardized Precipitation and Evaporation Index (SPEI) data and satellite-derived Enhanced Vegetation Index (EVI) products to quantify the temporal stability (ratio of mean annual EVI to its SD), resistance (ability to maintain its original levels during droughts), and resilience (rate of EVI recovering to pre-drought levels) at biome and global scales. We identified significantly increasing trends of annual drought severity (SPEI range: -0.08 to -1.80), area (areal fraction range: 2%-19%), and duration (month range: 7.9-9.1) in the EBF biome over 2000-2014. However, EBFs showed the highest resistance of EVI to droughts, but no significant differences in resilience of EVI to droughts were found among biomes (forests, grasslands, savannas, and shrublands). Global resistance and resilience of EVI to droughts were largely affected by temperature and solar radiation. These findings suggest that EBFs have higher stability than other biomes despite the greater drought exposure. Thus, the conservation of EBFs is critical for stabilizing global vegetation productivity and land carbon sink under more-intense climate extremes in the future.

基于MODIS数据的神农架大九湖泥炭藓沼泽植被指数变化研究

PDF HTML阅读 XML下载 导出引用 引用提醒 基于MODIS数据的神农架大九湖泥炭藓沼泽植被指数变化研究 DOI: 10.5846/stxb201806231381 作者: 作者单位: 杭州师范大学遥感与地球科学研究院,杭州师范大学遥感与地球科学研究院,浙江安吉小鲵国家级自然保护区,杭州师范大学遥感与地球科学研究院,杭州师范大学生命与环境科学研究院,杭州师范大学遥感与地球科学研究院 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（41571049）；浙江省自然科学基金（LY16D010007）；杭州市科技计划项目（20170533B01） Vegetation index change of Sphagnum palustre bog in Dajiu Lake of Mt. Shennongjia based on MODIS data Author: Affiliation: Research Academy of Remote Sensing and Earth Sciences, Hangzhou Normal University,Research Academy of Remote Sensing and Earth Sciences, Hangzhou Normal University,Zhejiang Hynobius Amjiensis National Nature Reserve,Research Academy of Remote Sensing and Earth Sciences, Hangzhou Normal University,College of Life and Environmental Sciences, Hangzhou Normal University,Research Academy of Remote Sensing and Earth Sciences, Hangzhou Normal University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:泥炭藓是陆地生态系统中最重要的固碳植物之一，固碳量约占全球土壤碳的15%。近几十年来，由全球气候变暖导致的泥炭藓沼泽水热状况变化对泥炭藓的固碳量和速率产生影响。选取我国最重要的亚高山泥炭沼泽--神农架大九湖泥炭藓沼泽为试验区，以分析中纬度地区泥炭藓沼泽植被生长状况受气候变化的影响。研究以2000-2017年MODIS植被指数NDVI和EVI为数据源，通过对比Logistic模型订正后的NDVI和EVI时间序列在泥炭藓沼泽植被生长状况监测中的优劣，选出最佳指标以获得18年来泥炭藓沼泽植被生长状况的变化趋势。研究结果表明：1）Logistic模型能够很好的消除泥炭藓沼泽植被指数时间序列的噪声；2）在季节和年际两个时间尺度上，EVI对泥炭藓沼泽植被生长状况的监测效果均优于NDVI。在季节周期上，虽然EVI和NDVI均得到泥炭藓沼泽植被生长周期规律，但EVI更灵敏。在年际分析中，EVI有更大的值域响应空间，以准确反映泥炭藓沼泽植被的年际变化规律；3）由EVI获得18年来泥炭藓沼泽植被变化趋势指出，泥炭藓沼泽植被呈显著微弱增长，年均EVI增长率为3.8‰（R2=0.45，P < 0.01）。相比于EVI年均值，EVI年内最大值（R2=0.47，P < 0.01）更敏锐的反映泥炭藓沼泽植被生长状况的动态变化。 Abstract:Sphagnum is one of the most important carbon sequestration plants in terrestrial ecosystem, which accounts for approximately 15% of global soil carbon. In recent decades, the changes in the hydrothermal status of Sphagnum bogs caused by global warming have directly affected the amount and rate of carbon fixed by Sphagnum. In this study, the most important subalpine peat bogs of China, the Mt. Shennongjia Dajiu Lake Sphagnum palustre bog, was selected as the experimental area to analyze the effect of climate change on the vegetation growth of Sphagnum bogs in the mid-latitude area. The Moderate Resolution Imaging Spectroradiometer (MODIS) vegetation indices NDVI (Normalized Difference Vegetation Index) and EVI (Enhanced Vegetation Index) were used as data sources from 2000-2017 to compare the advantages and disadvantages of NDVI and EVI time series, revised by the logistic model in monitoring the vegetation growth status of Sphagnum bogs. The best index was selected to obtain the change trend of Sphagnum bogs vegetation growth in the past 18 years. The results showed that: (1) the logistic model can effectively eliminate the noise on the time series of Sphagnum palustre bog vegetation index. (2) in the seasonal and annual time scales, the EVI monitors the vegetation growth of Sphagnum palustre bog better than NDVI. In the seasonal scale, although both EVI and NDVI reflected the regularity of the growth cycle of Sphagnum palustre bog vegetation, EVI was more sensitive to the time period of the change. In the annual analysis, EVI had a greater range of response space to accurately reflect the annual variation of Sphagnum palustre bog vegetation. (3) the change in the trend of Sphagnum palustre bog vegetation in the past 18 years was obtained by EVI, it was found that the annual average growth rate of Sphagnum palustre bog vegetation showed a remarkably steady growth, with an average annual EVI growth rate of 3.8‰ (R2=0.45, P < 0.01). Compared with the annual average of EVI, the annual maximum (R2=0.47,P < 0.01) reflects the dynamic changes of Sphagnum palustre bog vegetation growth more sensitively. 参考文献 相似文献 引证文献

Quantifying Climate Change and Ecological Responses within the Yangtze River Basin, China

The interactions between climate change and vegetation have a significant impact on the dynamics of the global carbon cycle. Based on the observed meteorological data from 1961 to 2013 and the temperature and precipitation data simulated by various climate models (simulations phase 5 of the Climate Model Intercomparison Project dataset), this paper analyzes the temperature and precipitation changes of the Yangtze River Basin (YRB) and finds that they are a similar trend, that is, the temperature presents a significant upward trend (R2 = 0.49, p &lt; 0.01), and the variation trend of precipitation is not significant (R2 = 0.01). Specifically, based on observed meteorological data, the annual mean temperature increased significantly and the area of increasing temperature accounted for 99.94% of the total region (p &lt; 0.05); however, there was no significant change in annual precipitation. Ecological indicators (normalized difference vegetation index (NDVI); enhanced vegetation index (EVI); leaf area index (LAI); gross primary production (GPP); and net primary production (NPP)) of the YRB showed an increasing trend, and annual NDVI, annual EVI, LAI, annual total GPP and annual total NPP increased at respective rates of 0.002 yr−1, 0.001 yr−1, 0.07 m2m−2decade−1, 9 TgCyr−1yr−1, and 6 TgCyr−1yr−1, respectively. Correlation analysis between temperature/precipitation and NDVI/EVI/LAI/GPP/NPP was used to determine the relationships between climatic parameters and ecological indicators. Specifically, the temperature is significantly positively correlated with annual NDVI (R2 = 0.37, p &lt; 0.05), with annual mean LAI (R2 = 0.35, p &lt; 0.05) and with annual GPP (R2 = 0.37, p &lt; 0.05). In addition, there is a moderate positive correlation between mean EVI and mean growing season air temperature (R2 = 0.24); annual mean air temperature is a moderate positive correlation with annual NPP (R2 = 0.28). Our findings confirm that temperature is more closely related to ecological factors than precipitation over the YRB in these decades.

Reanalysis of global terrestrial vegetation trends from MODIS products: Browning or greening?

Accurately monitoring global vegetation dynamics with modern remote sensing is critical for understanding the functions and processes of the biosphere and its interactions with the planetary climate. The MODerate resolution Imaging Spectroradiometer (MODIS) vegetation index (VI) product has been a primary data source for this purpose. To date, the MODIS team had released several versions of VI products that have widely used in global change studies and practical applications. In this study, we re-examined the global vegetation activity by comparing the recent MODIS Collection 6 (C6) VIs with Collection 5 (C5) VIs including Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) from Terra (2001–2015) and Aqua Satellites (2003–2015). We found substantial differences in global vegetation trends betweenTerra-C5 and -C6 VIs, especially EVI. From 2001 to 2015, global vegetation showed a remarkable greening trend in annual EVI from the Terra-C6 (0.28% year−1; P<0.001), in contrast to the decreasing EVI trend from the Terra-C5 (−0.14% year−1, P<0.01). Spatially, large portions of the browning areas in tropical regions identified by Terra-C5 VIs were not evident in Terra-C6 VIs. In contrast, the widespread greening areas in Terra-C6 VIs were consistent with Aqua-C6 VIs and GIMMS3g NDVI. Our finding of a greening Earth supports the recent studies suggesting an enhanced land carbon sink. Our study suggests that most of the vegetation browning trends detected by MODIS Terra-C5 VIs were likely caused by sensor degradation, particularly for the period after 2007. Therefore, previous studies of temporal vegetation trends based solely on Terra-C5 VIs may need to be reevaluated. Our new analysis offers the most updated understanding of the global vegetation dynamics during the past 15years and contributes to accurately understanding the role of vegetation played in the Earth's biogeochemical and climatic systems.

Leaf and stand-level carbon uptake of a Mediterranean forest estimated using the satellite-derived reflectance indices EVI and PRI

Various aspects of global environmental change affect plant photosynthesis, the primary carbon input in ecosystems. Thus, accurate methods of measuring plant photosynthesis are important. Remotely sensed spectral indices can monitor in detail the green biomass of ecosystems, which provides a measure of potential photosynthetic capacity. In evergreen vegetation types, however, such as Mediterranean forests, the amount of green biomass changes little during the growing season and, therefore, changes in green biomass are not responsible for changes in photosynthetic rates in those forests. This study examined the net photosynthetic rates and the diametric increment of stems in a Mediterranean forest dominated by Quercus ilex using three spectral indices (normalized difference vegetation index (NDVI), enhanced vegetation index (EVI), and photochemical reflectance index (PRI)) derived from Moderate Resolution Imaging Spectroradiometer (MODIS) sensors. Average annual EVI accounted for 83% of the variability of the diametric increment of Q. ilex stems over a 10 year period. NDVI was marginally correlated with the diametric increment of stems. This study was the first to identify a significant correlation between net photosynthetic rates and radiation use efficiency at the leaf level using PRI derived from satellite data analysed at the ecosystem level. These results suggest that each spectral index provided different and complementary information about ecosystem carbon uptake in a Mediterranean Q. ilex forest.

Vegetation indices changes in the cloud forest of La Gomera Island (Canary Islands) and their hydrological implications

AbstractVegetation indices derived from remote sensing data still remain to be used for analysing the relationship between climatic factors and vegetation seasonal phenology in middle latitudes with subtropical conditions forests such as the Canarian laurel forest. The Garajonay National Park, located in the La Gomera Island, protects one of the best preserved examples of the Macaronesian laurel forest, due to the cloud banks produced by trade winds, with rainfall and temperature field data showing a clear Mediterranean climatic pattern. We have analysed seasonal vegetation indices trend for different types of forest inside the Garajonay National Park using normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI) products derived from moderate resolution imaging spectrometer (MODIS) Aqua data for two hydrological years (October 2003 to September 2005) in relationship with the existing field climatic data: rainfall, net fog water and temperature. Maximum annual EVI maps show the highest vegetation indices in the laurel forest of La Gomera that occur during the dry season, mainly in late spring to early summer, with EVI temporal profiles showing that valley‐bottom laurel forest areas have the most clear seasonal trend. Difference maps of EVI values between months with the lowest and highest rainfall of each hydrological year clearly confirm the highest photosynthetic activity in the laurel forest during the dry season. In addition, these forests show a significative temporal correlation between EVI values and the temperature in the forest (p &lt; 0·001). Our results prove the absence of summer drought stress in the laurel forest implying that the fog drip income is high enough to maintain enough soil moisture to allow the forest fully transpire when temperatures are higher. As the laurel forest of La Gomera occurs in the main recharge area of the island's aquifer system, our analysis of EVI data suggests that fog drip constitutes a key hydrological factor. Copyright © 2010 John Wiley &amp; Sons, Ltd.