Research investigating the estimation ability of forest stock volume combining multiband polarimetric SAR(PolSAR)has hardly been explored,particularly the complementarity between long wavelengths,such as P-band and other shorter wavelengths.This study takes cold temperate coniferous forests in Inner Mongolia as the research object.Having available a multiband stack of airborne P-,L-,S-,C-,and X-band PolSAR data acquired by the high-resolution airborne multidimensional space joint-observation SAR(MSJosSAR)system,the aim is to analyze systematically the response and sensitivity of polarimetric characteristics in different bands to forest stock and evaluate the performance of forest stock retrieval using single and multiband PolSAR data.First,geocoding and terrain radiometric correction were performed on multiband PolSAR data,and then a polarimetric feature set containing backscatter intensity and polarization decomposition components was extracted.Second,on the basis of the water cloud model and correlation coefficient,the response law and sensitivity of polarimetric characteristics in different bands to forest stock was analyzed.Finally,machine learning algorithms were used to perform feature selection and modeling,and the ability of each band and jointly with multiband to estimate forest stock was evaluated.The response of backscatter intensity in different bands to forest stock shows a similar upward trend,but the saturation point varies depending on wavelength and polarimetric channel.Among them,the saturation point for the P-band is higher than 160 m3/ha,whereas it does not exceed 110 m3/ha for the other bands.In addition,the correlation between forest stock and the P-band,L/S-band,and C/X-band decreases in order,with values above 0.6,between 0.3 and 0.4,and below 0.3,respectively.When forest stock was estimated on the basis of a single band,the accuracy of the P-band was 73.79％,and the accuracy of other bands did not exceed 60％.When multiband joint estimation was used,the estimation accuracy of L-or S-band and P-band joint estimation was approximately 2％higher than using P-band alone.The contribution of adding the C-or X-band to the accuracy improvement was minimal.The best estimation performance was achieved through the combination of all bands with an accuracy of 77.25％.Considering various indicators,such as signal dynamic range,saturation point,and correlation,the P-band exhibits the highest sensitivity to forest stock,followed by the L/S-band,and the C/X-band,which is the least sensitive.Therefore,when estimating forest stock using PolSAR data,the P-band should be the first choice.Additionally,when using multiband joint estimation,the combination of P-and L-or S-band should be preferred.In recent years,long-wavelength SAR satellites are being vigorously developed from China and overseas,e.g.,China's LT-1 satellite is already in orbit,ESA BIOMASS and NASA-ISRO NISAR missions are about to be launched,and China's civil P-band SAR satellite has also entered the preliminary research stage.The above long-wavelength SAR satellites will greatly enhance the estimation ability of regional forest stock in our country and provide strong support for the refined and scientific management of forest resources.
remote sensingmulti-band SARpolarimetric SARsaturation pointforest stockwater cloud model
维普
万方数据
