基于Sentinel-1和Sentinel-2A的西小山林场平均树高估测

森林资源调查对于我国森林生态系统可持续发展具有重要意义,森林平均高度是森林资源调查的主要结构参数,也是获取难度最大的关键参数之一。为探究联合主被动遥感技术在估测森林平均高度方面的潜力,本研究以吉林省临江市西小山林场为研究区,利用Sentinel-1 SAR和Sentinel-2A数据,通过提取Sentinel-1的2个后向散射系数、8个纹理信息,以及Sentinel-2A的10个光谱波段及其纹理信息和11个植被指数,采用多元线性回归方法分别建立基于上述变量以及融合4类变量的5组平均树高估算模型,并评估各变量对反演精度的影响。结果表明: 单一数据源变量中,基于Sentinel-2A光谱波段提取的纹理信息建模效果较好,能够作为估算森林平均高度的有效数据;融合4类变量的森林平均高度估算模型最优,R²达0.56、留一交叉验证均方根误差为2.92 m、相对留一交叉验证均方根误差为21.5%。基于Sentinel-1与Sentinel-2A特征变量的平均树高模型能够提高森林高度的估算精度,可用于区域森林平均高度估测和制图。

Estimating average tree height in Xixiaoshan Forest Farm,Northeast China based on Sentinel-1 with Sentinel-2A data

Forest resource survey is important for the sustainable development of forest ecosystem in China. The average tree height is a main structural parameter of forest resource survey, and also one of the key parameters with greatest difficulty to obtain. The purpose of this study was to explore the potential of joint active and passive remote sensing technology in estimating forest average height. Taking Xixiaoshan Forest Farm in Linjiang City of Jilin Province as the research area, we used Sentinel-1 SAR and Sentinel-2A data, extracted two backscatter coefficients and eight texture information of Sentinel-1, ten spectral bands and texture information of Sentinel-2A and eleven vegetation index variables, constructed five groups of average tree height estimation models based on above variables and fusion of four variables by multiple linear regression method. We further evaluated the influence of each variable on the inversion accuracy. The results showed that the texture information extracted from the Sentinel-2A spectral band of a single data source variable had a better modeling effect and could be used as effective data to estimate the average tree height. The height estimation model of the integrated four variables was optimal, with a R² vaule of 0.56, a root mean square error of leave-one-out cross-validation of 2.92 m, and a relative root mean square error of leave-one-out cross-validation of 21.5%. The forest average height model based on Sentinel-1 and Sentinel-2a characteristic variables could improve the estimation accuracy of forest height, which could be used for regional forest average height estimation and mapping.