A simple Landsat–MODIS fusion approach for monitoring seasonal evapotranspiration at 30 m spatial resolution
A simple Landsat–MODIS fusion approach for monitoring seasonal evapotranspiration at 30 m spatial resolution
复制标题
DOI：
10.1080/01431161.2014.990645
复制
发表时间：
2015-01
影响因子：
3.4
通讯作者：
N. Bhattarai;Lindi J. Quackenbush;M. Dougherty;L. Marzen
中科院分区：
文献类型：
--
作者：
N. Bhattarai;Lindi J. Quackenbush;M. Dougherty;L. Marzen
美国东南部潮湿地区的持续云量和陆地卫星传感器的低时间分辨率限制了中等空间分辨率下季节性蒸散（ET）图的推导。本文介绍了一种Landsat-MODIS（Landsat-ModerateResolutionImagingSpectroradiometer）ET融合模型，该模型利用简单线性回归将Landsat-MODIS高分辨率ET与METRIC（InternalizedCalibration）模型和植被温度条件指数（VTCI）融合。对于佛罗里达的一个研究地点，在佛罗里达费里斯农场的美国地质调查局（USGS）站，模型估计的ET和使用能量收支涡度协方差估计的ET具有良好的一致性，均方根误差为0.44 mm day-1，决定系数（R2）为0.80，Nash-Sutcliffe效率为0.79，2001年生长季累积蒸散量的相对误差为2%。在亚拉巴马的另一个研究地点，该模型低估了2008年鱼河流域的年度水平衡ET为39毫米或4%。模型估计的ET与使用非融合Landsat仅在两个站点的方法得到的比较表明，Landsat和MODIS ET值的融合减少了ET估计的潜在错误，否则会出现由于没有足够的无云Landsat图像的METRIC处理。验证结果和应用模型在推导季节/年度ET不同的土地覆盖类在鱼河流域表明，融合模型有可能被用于连续监测ET领域流域级农业和水文应用在美国东南部。
Persistent cloud-cover in the humid southeastern USA and the low temporal resolution of Landsat sensors limit the derivation of seasonal evapotranspiration (ET) maps at moderate spatial resolution. This article introduces a Landsat Moderate Resolution Imaging Spectroradiometer (Landsat–MODIS) ET fusion model that uses simple linear regression to integrate Landsat-derived reference ET fraction (ETrF) from mapping ET at high resolution with internalized calibration (METRIC) model and the vegetation temperature condition index (VTCI) derived from MODIS images. For a study site in Florida, model-estimated ET and ET estimated using energy budget eddy covariance at a US Geological Survey (USGS) station in Ferris Farm, Florida, were found to be in a good agreement with a root mean squared error of 0.44 mm day–1, coefficient of determination (R2) of 0.80, Nash–Sutcliffe efficiency of 0.79 for daily ET (ETd), and 2% relative error for cumulative seasonal ET during the growing season of 2001. At another study site in Alabama, the model underestimated 2008 annual water balance ET for the Fish River Watershed by 39 mm or 4%. Comparisons of model-estimated ET with that obtained using a non-fusion Landsat-only approach at both sites indicated that the fusion of Landsat and MODIS ET values reduces potential errors in ET estimation that would otherwise arise due to insufficient availability of cloud-free Landsat images for METRIC processing. Validation results and application of the model in deriving seasonal/annual ET for different land-cover classes in the Fish River Watershed suggested that the fusion model has the potential to be used in continuously monitoring ET for field- to watershed-level agricultural and hydrological applications in the southeastern USA.