天基载荷特性光谱分辨率与信噪比对黑土地有机质定量反演影响分析

Sensitivity of Black Soil Organic Matter Content Prediction to the Spectral Resolution and Signal-to-Noise Ratio of Space-based Remote Sensing Loads

天基黑土地有机质含量高精度监测对黑土资源利用与保护具有重要意义,基于天基高光谱数据的土壤有机质含量预测是实现大区域土壤高时空覆盖监测的有效手段。星载高光谱仪器的光谱分辨率和信噪比等核心参数直接影响土壤有机质含量预测的精度。为进一步提高我国黑土区土壤有机质监测水平,为黑土地农业资源环境监测卫星系统设计提供理论支撑。基于卫星光学载荷光谱分辨率、信噪比对土壤有机质含量反演影响研究,构建了基于MODTRAN大气传输模型、仪器信噪比分析模型以及偏最小二乘回归土壤有机质反演模型的面向黑土监测的高光谱卫星“仪器—观测—反演”全链路分析模型,并以东北典型黑土区三江平原土壤实测数据为模型输入,将实验室测得的黑土区土壤光谱数据仿真成加入大气效应以及真实天基遥感仪器特性的模拟数据,针对改变光谱分辨率及信噪比参数的反演结果进行对比分析,结果表明:①针对黑土有机质含量预测的天基遥感载荷光谱分辨率参数在小于40 nm区间反演性能较好,RMSE<0.60%,R2>0.75;②当光谱分辨率为15 nm、加权信噪比大于等于477.31时,黑土地有机质反演性能最优,RMSE<0.535%;③光谱分辨率越小,噪声的影响越显著,且光谱间隔越小,信噪比需求越高。10 nm、20 nm分辨率时对应的最佳加权信噪比为494.07、462.16,60 nm、100 nm处的最低加权信噪比需求分别为358.84、275.63。

The high precision monitoring of the organic matter content of space-based black soil is of great signif⁃icance to the utilization and conservation of black soil resources.Soil organic matter content prediction based on space-based hyperspectral data is an effective means to achieve high spatial and temporal soil coverage monitor⁃ing in large regions.The core parameters such as spectral resolution and signal-to-noise ratio of satellite-based hyperspectral instruments have a significant impact on the accuracy of soil organic matter content prediction.This paper aims to improve the level of soil organic matter monitoring in the black soil region of China.In this paper,to improve the level of soil organic matter monitoring in the black soil region of China,we conducted a study on the influence of spectral resolution and signal-to-noise ratio of satellite optical payload on soil organic matter content inversion,and constructed a hyperspectral satellite"instrument-observation-inversion"model for black soil monitoring based on MODTRAN atmospheric transmission model,instrument signal-to-noise ratio analysis model and partial least squares regression soil organic matter inversion model.And using the actual soil measurement data of Sanjiang Plain,a typical black soil area in northeast China,as model input,the soil spec⁃tral data measured in the laboratory in the black soil area is simulated into simulated data incorporating atmo⁃spheric effects and the characteristics of real space-based remote sensing instruments,and the inversion results are compared and analyzed for changing the spectral resolution and signal-to-noise ratio parameters,and the re⁃sults show that:(1)The inversion performance of space-based remote sensing load spectral resolution parame⁃ter for black soil organic matter content prediction is better in the interval less than 40 nm,with RMSE<0.60%and R2>0.75;(2)When the spectral resolution is 15nm and the weighted signal-to-noise ratio is greater than or equal to 477.31,the inversion performance of black soil organic matter is optimal,with RMSE<0.535%;(3)The smaller the spectral resolution,the more significant the effect of noise,and the smaller the spectral in⁃terval,the higher the signal-to-noise ratio requirement.the best weighted signal-to-noise ratios at 10 nm and 20 nm resolution correspond to 494.07 and 462.16,and the minimum weighted signal-to-noise ratio require⁃ments at 60 nm and 100 nm are 358.84 and 275.63,respectively.