主成分分析法在树基沟矿区植被反射光谱研究中的应用

Application of Principal Component Analysis in the Study of Vegetation Reflectance Spectra in Shujigou Mining Area

树基沟作为红透山-树基沟铜锌矿的一个重要矿区,目前仍有较大的找矿空间,然而其较高的植被覆盖率掩盖了地表的矿化蚀变信息,增加了常规找矿难度。若能间接利用地表植被的反射光谱探测隐伏地下的矿产则为找矿提供了新思路。本研究测量了矿区多个采样点位长白落叶松针叶的反射光谱,并利用主成分分析法评价了反射光谱的主要受控波段。结果表明:第一主成分(PC1)对长白落叶松反射光谱的累积贡献率占70. 259%,第二主成分(PC2)占23. 212%; PC1概括说明了400～2500nm波段范围内的光谱反射率主要受550nm、552nm及近红外波段700～1100nm之间光谱反射率的控制,其对应着75%的采样点位; PC2受439nm、445nm、460nm、500nm、510nm及短波红外1440～2209nm之间光谱反射率的控制,对应的点位约8. 33%。这为今后有效利用反射光谱的"指纹效应"圈定地下隐伏矿(化)体提供理论依据。

As one important mining area of Hongtoushan-Shujigou Copper-Zinc ore,there is still a large prospecting space in Shujigou village,but its high vegetation coverage covers the surface mineralized alteration information,increases the conventional prospecting difficulty.Nevertheless,incidentndirect detection of concealed underground minerals using the reflection spectrum of the vegetation will provide a newidea of prospecting. Reflectance spectra of Larix olgensis needles in several sampling points were measured,and the principal component analysis was used to determine which bands properly reflected the variation of reflec-tance spectrum,which will provide a theoretical basis for delineating underground hidden orebodies in the future. The result shows that the effects of the first principal component on the reflectance spectra of Larix olgensis accounted for 70. 259%,and the second principal components accounted for 23. 212%. The first principal component generalizes that the spectral reflectivity in the range of 400 ～ 2500 nm band is mainly controlled by spectral reflectivity between 550 nm,552 nm and 700 ～ 1100 nm in near-infrared band,which corresponds to 75% sampling sites. The second principal component generalizes the spectral reflectivity in the range of 400 ～ 2500 nm band is mainly controlled by 439 nm,445 nm,460 nm,500 nm,510 nm and short wave infrared 1440 ～ 2209 nm,and the corresponding number of sampling sites is about 8. 33%.