Day 38 气候变化对NDVI的影响

Abstract：On the basis of land use/land cover map, satellite derived images of NDVI, air temperature and precipitation, the correlations between NDVI-air temperature and NDVI-precipitation over time period of 1987–2016 in inter-annual/monthly scales were analyzed. The present study investigated the relationships between inter-annual/monthly variations of climate features and the fluctuations of NDVI by four vegetation types in Mashhad-Chenaran plain, northeast of Iran. It was revealed that yearly precipitation by all vegetation types has close correlations with NDVI fluctuations. The inter-annual NDVI-precipitation showed that rich ranges were most affected by precipitation, followed by moderate ranges, dry farming and irrigated farming, where the correlation coefficient R varied between 0.419 and 0.488 (P ≤ 0.05), (P ≤ 0.01). Furthermore, the correlations between monthly NDVI-air temperature by all vegetation types were remarkably significant. The responses of the NDVI to monthly variations of air temperature exhibited that rich range were most affected by monthly temperature fluctuations followed by dry farming, moderate range, and irrigated farming. Accordingly, the values of correlation coefficient R ranged from 0.769 to 0.845 (P ≤ 0.01). The finding results confirmed the utility of NDVI index to express vegetation variability in semi-arid climate conditions and improved our knowledge about the relations between climate features and vegetation growth for rehabilitation programs in watershed scale.Keywords：Climate change · Air temperature · Precipitation · NDVI · Remote sensing · GIS

基于用地类型图，本研究分析了1987-2016年期间NDVI、气温和降水的卫星影像，在年际/月尺度上分析了NDVI-air温度和NDVI-降水量之间的相关性。本文研究了伊朗东北部马什哈德-钦纳兰平原4种植被类型的年际/月变化与NDVI变化的关系。结果表明，各植被类型的年降水量与NDVI的波动密切相关。各月NDVI和空气温度的相关性十分显著。本研究确认了使用NDVI来表示植被在半干旱气候状况下的实用性，也进一步研究了流域内气候特点和植被修复计划的关系

本研究的主要目的是评估NDVI作为植被指数和四个主要气候因子温度，降水，土壤，根部水分之间的关系，来找到影响NDVI的最关键气候因子。

方法

本文将降水气温等要素因子和NDVI共同可视化，同时用SPSS对其相关性进行计算，得到因子之间的相关性。将土地利用类型分为灌溉农田，干燥农田，富饶的牧场和适中的牧场进行分类研究。

结果

结果显示，年降水量的波动和NDVI的波动有着很强的相关性，但是年气温波动和NDVI没有显著关系。NDVI随着年降水的变化而变化。这揭示年降水和NDVI有着很强的相关性，而气温和NDVI的关系可以忽略不计。月气温的波动对于NDVI有着显著的影响，而月降水量的波动对于NDVI的影响并不大。

不同植被也对这几种因子相关性也不一样，通过计算不同植被类型的NDVI可以展示气候因子对于NDVI波动的影响。

各植被类型的降水量与NDVI之间存在显著的相关性，降水的月变化对研究区任何植被类型的NDVI值均无显著影响。

研究区十年间NDVI波动分带图NDVI值呈现递增趋势

结论

本研究分析了1987-2016年间月/年尺度上NDVI与气温、降水量的年际和月际关系，以评估伊朗东北部马什哈德平原四种主要土地利用/土地覆盖类型的NDVI与气候特征的相关性。相关系数表明NDVI和气候特点之间存在着紧密的关系，受降水影响显著的植被类型为丰富型、中度型、旱作型和灌溉型。本研究结果可以帮助决策者提供答案，以应对气候条件的变化对研究区植物植被构成的挑战。

TCL碎碎念

看这篇文献就感觉很迷惑emmmm，因为后面十来页全都是NDVI的图，感觉前面的研究内容也没有说特别困难。主要还是一些相关系数的分析操作，可能是因为这个主题比较新又没有人研究过的关系吧