Soil, Water, and Environmental Science (SWES), University of Arizona, Tucson, AZ 85719, USA.
US Geological Survey, Southwest Biological Science Center, University of Arizona, 520 N. Park Avenue, Tucson, AZ 85719, USA.
Sensors (Basel). 2018 May 13;18(5):1546. doi: 10.3390/s18051546.
The Enhanced Vegetation Index (EVI) is a key Earth science parameter used to assess vegetation, originally developed and calibrated for the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Terra and Aqua satellites. With the impending decommissioning of the MODIS sensors by the year 2020/2022, alternative platforms will need to be used to estimate EVI. We compared Landsat 5 (2000⁻2011), 8 (2013⁻2016) and the Visible Infrared Imaging Radiometer Suite (VIIRS; 2013⁻2016) to MODIS EVI (2000⁻2016) over a 420,083-ha area of the arid lower Colorado River Delta in Mexico. Over large areas with mixed land cover or agricultural fields, we found high correspondence between Landsat and MODIS EVI (R² = 0.93 for the entire area studied and 0.97 for agricultural fields), but the relationship was weak over bare soil (R² = 0.27) and riparian vegetation (R² = 0.48). The correlation between MODIS and Landsat EVI was higher over large, homogeneous areas and was generally lower in narrow riparian areas. VIIRS and MODIS EVI were highly similar (R² = 0.99 for the entire area studied) and did not show the same decrease in performance in smaller, narrower regions as Landsat. Landsat and VIIRS provide EVI estimates of similar quality and characteristics to MODIS, but scale, seasonality and land cover type(s) should be considered before implementing Landsat EVI in a particular area.
增强型植被指数 (EVI) 是评估植被的关键地球科学参数，最初是为 Terra 和 Aqua 卫星上的中分辨率成像光谱仪 (MODIS) 开发和校准的。随着 MODIS 传感器在 2020/2022 年即将退役，需要使用替代平台来估算 EVI。我们将 Landsat 5（2000-2011 年）、8（2013-2016 年）和可见红外成像辐射套件（VIIRS；2013-2016 年）与 MODIS EVI（2000-2016 年）进行了比较，研究区域为墨西哥干旱的下科罗拉多河三角洲的 420,083 公顷。在混合土地覆盖或农田的大面积区域，我们发现 Landsat 和 MODIS EVI 之间具有高度相关性（整个研究区域的 R² = 0.93，农田的 R² = 0.97），但在裸土（R² = 0.27）和河岸植被（R² = 0.48）上相关性较弱。MODIS 和 Landsat EVI 之间的相关性在大面积、同质性区域较高，在狭窄的河岸区域则通常较低。VIIRS 和 MODIS EVI 高度相似（整个研究区域的 R² = 0.99），并且在较小、较窄的区域中，性能下降的情况与 Landsat 不同。Landsat 和 VIIRS 提供的 EVI 估计具有与 MODIS 相似的质量和特征，但在特定区域实施 Landsat EVI 之前，应考虑规模、季节性和土地覆盖类型。
