Remote-sensing satellite images provided rapid and continuous spectral and spatial information of the land surface in the Sougia River catchment by identifying the major changes that have taken place over 20 years (1995–2015). Vegetation indices (VIs) of normalized difference vegetation index (NDVI), enhanced vegetation index (EVI) and leaf area index were derived for monitoring and mapping variations in vegetation cover. The quantified decrease in NDVI was found to be 4% between 1995 and 2005, and further decreased by 77.1% between 2005 and 2015; it declined back to almost the initial status of 1995. EVI results were inconsistent suggesting that seasonal crops influence the temporal distribution of vegetation cover. The temporal variations in the VIs were important input parameters for the modelling and management of the catchment’s hydrological behaviour. Image classification found that the 4- and the 6-class classifications between 1995 and 2005 were unstable and produced, respectively, a 13.8% and 16.2% total change between classes. Meanwhile, the 8-, 10- and the 12-class showed an almost horizontal line with a minor fluctuation of less than 0.05%. The results of the post-classification change detection analysis indicated a land degradation in terms of natural vegetation losses with sparser or even with no natural vegetation cover.

中文翻译：

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使用遥感技术在希腊克里特岛进行森林覆盖率评估

遥感卫星图像通过识别20年来（1995年至2015年）发生的重大变化，提供了苏贾河流域陆地表面的快速，连续的光谱和空间信息。导出归一化差异植被指数（NDVI），增强植被指数（EVI）和叶面积指数的植被指数（VIs），以监测和绘制植被覆盖度变化图。在1995年至2005年之间，NDVI的量化下降幅度为4％，在2005年至2015年之间进一步下降了77.1％。它回落到几乎1995年的初始状态。EVI结果不一致，表明季节性作物影响植被覆盖的时间分布。VI的时间变化是流域水文行为建模和管理的重要输入参数。图像分类发现，1995年至2005年的4级和6级分类是不稳定的，产生的结果是，各级之间的总变化分别为13.8％和16.2％。同时，8级，10级和12级显示几乎水平的线，细微波动小于0.05％。分类后变化检测分析的结果表明，就自然植被的损失而言，土地退化是稀疏的，甚至没有自然植被的覆盖。10级和12级显示几乎水平的线，细微波动小于0.05％。分类后变化检测分析的结果表明，就自然植被的损失而言，土地退化是稀疏的，甚至没有自然植被的覆盖。10级和12级显示几乎水平的线，细微波动小于0.05％。分类后变化检测分析的结果表明，就自然植被的损失而言，土地退化是稀疏的，甚至没有自然植被的覆盖。