Modelling directional effects on remotely sensed land surface temperature
Modelling directional effects on remotely sensed land surface temperature
复制标题
DOI：
10.1016/j.rse.2016.12.008
复制
发表时间：
2017-03-01
影响因子：
13.5
通讯作者：
Remedios, John
中科院分区：
文献类型：
--
作者：
Ermida, Sofia L.;DaCamara, Carlos C.;Remedios, John
地表温度是一个方向性很强的变量，其遥感测量受观测和光照几何条件的影响很大。本研究提出了使用LST产品搭配在空间和时间，但获得不同的视角，校准一个简单的模型能够表征LST的角度变化。这次演习使用中分辨率成像分光仪（Aqua和Terra）和SEVIRI（气象卫星）LST产品，覆盖地中海欧洲和北方非洲，涵盖2011、2012、2013和2014年全年。该方法依赖于由“发射率核”和“太阳能核”组成的核模型，分别与观测角各向异性和表面上的阴影/阳光照射效应相关联。核系数的空间分布反映了景观的特点，无论是在植被覆盖和地形。模型的性能是通过几个比较演习在4年的分析期间进行评估。交叉验证的结果表明，由核模型的角度校正导致SEVIRI和MODIS白天（夜间）LST产品之间的均方根差的减少，从原来的未校正值的3.5 K（1.5 K）到2.3 K（1.3 K）。MSG和MODIS的LST产品对现场白天测量收集了2年多的验证站点在埃武拉（葡萄牙）的比较表明，角度校正导致减少均方根误差从4.6 K（2.0 K）到3.8 K（1.9 K）的MODIS（SEVIRI）。核模型可以是量化与视角和照明角度相关联的LST不确定性的有用工具。(C)2016 Elsevier Inc. All rights reserved.
Land surface temperature (LST) is a markedly directional variable and its remotely sensed measurement may be strongly affected by viewing and illumination geometries. This study proposes the use of LST products collocated in space and time, but obtained with different viewing angles, to calibrate a simple model capable of characterizing the LST angular variability. The exercise is performed using MODIS (Aqua and Terra) and SEVIRI (Meteosat) LST products, for an area covering Mediterranean Europe and Northern Africa and encompassing the full years of 2011,2012, 2013 and 2014. The approach relies on a kernel model that is composed by an "emissivity kernel" and a "solar kernel", associated to observation angle anisotropy and to shadowing/sunlit effects on the surface, respectively. The spatial distribution of the kernel coefficients is shown to reflect characteristics of the landscape, both in terms of vegetation cover and topography. Model performance is assessed through several comparison exercises over the 4-year period under analysis. Cross-validation results show that the angular correction by the kernel model leads to a decrease of the root mean square difference between SEVIRI and MODIS daytime (night-time) LST products, from the original uncorrected values of 3.5 K (1.5 K) to 2.3 K (1.3 K). Comparison of both MSG and MODIS LST products against in situ daytime measurements gathered over 2 years at a validation site in Evora (Portugal) reveals that the angular correction leads to a decrease in root mean square error from 4.6 K (2.0 K) to 3.8 K (1.9 K) for MODIS (SEVIRI). The kernel model may be a useful tool to quantify the LST uncertainties associated with viewing and illumination angles. (C) 2016 Elsevier Inc. All rights reserved.