退化伊犁绢蒿荒漠草地群落特征与地面光谱反射率相关性分析

利用便携式光谱仪,采集围栏内外伊犁绢蒿(Seriphidium transiliense)荒漠草地群落的光谱反射率,并测定其群落数量特征,研究两者之间的相关性,围栏内外对比,并筛选出敏感波段进行回归分析,建立预测模型。结果表明:围封的退化伊犁绢蒿荒漠草地得到了一定恢复;一阶微分后的光谱数据与草地群落的相关性明显提高,归一化不但可以提高相关水平,更加突出了围栏内外的差异;根据筛选出的敏感波段做回归分析,比较显著性和相关性,确定预测模型,围栏外盖度以677.4~729.6nm波段建立,y=-232746x3+65081x2-5386.9x+165,相关系数达到0.82(P0.01),围栏内盖度以622~754.3nm波段建立,y=-1040.5x2+526.78x-8.3912,相关系数为0.73(P0.01);围栏外地上生物量以1 904nm和624.8~734.9nm波段建立,y=0.0773x2-6.5177x+159.41,y=10.46e8.7018x,相关系数分别为-0.86(P0.01)和0.86(P0.01);围栏内地上生物量以622~729.6nm波段建立,y=2875x2-328.02x+46.013,相关系数为0.82(P0.05),而地面光谱反射率及两种处理方法与群落的平均高度、密度相关性较低。

Correlation between Community Characteristics and Spectral Reflectance of the Ground on Degraded Seriphidium transiliense Desert Grassland

Using the portable spectrometer,the spectral reflectance of the grassland community of S.transiliense was collected from inside and outside the fence.Community quantitative characteristics was determined,correlation between community and ground spectral correlation was researched,inside and outside the fence was contrasted,the sensitive bands was selected to carry on the regression analysis,and prediction model was established.The results showed that the degraded S.transiliense desert grassland with enclosure had been effectively restored;that the correlation between the spectral data and the first derivative of the grassland community improved.It not only improved the level of the normalized correlation,but difference between inside and outside the fence was more prominent;regression analysis according to the selected sensitive bands and comparing significance and correlation determined the prediction model.The coverage of the outside fence was y=-232746x3 +-65081x2-5386.9x+ 165 using 677.4～729.6 nm band,and the correlation coefficient was 0.82 (P＜0.01);the coverage inside the fence was y=-1040.5x2+ 526.78x-8.3912 using 622～754.3 nm band,and the correlation coefficient was 0.73(P＜0.01);the outside biomass of the fence was y=0.0773x2-6.5177x+159.41 and y=10.46e8.7018x,using 1 904 nm and 624.8～734.9 nm band,and the correlation coefficients were-0.86(P＜0.01) and 0.86(P＜0.01);the inside biomass of the fence was y=2875x2-328.02x+46.013 based on the 622～729.6 nm band,and the correlation coefficient was 0.82 (P＜0.05);and correlation between the ground spectral reflectance and two treatments with the average height and the population density was lower.