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利用典型地物高光谱数据和TM遥感影像,对毛乌素沙地处于旺盛生长期(7—9月)的由苔藓结皮主导的生物结皮进行了提取研究。结果表明:1苔藓结皮在生长期具有与绿色植物相似的光谱曲线变化趋势;红边参数显示,二者除红边位置非常接近外,红边振幅、红边宽度和红边面积差异均较大;在近红外区域,苔藓结皮比绿色植物的反射率低很多;苔藓结皮无明显的553 nm反射峰;低盖度苔藓结皮(33%)、藻类结皮和植被枯落物在整个波段光谱曲线比较接近,与裸沙相比,三者反射率均较低。2基于TM影像,用生物结皮指数(BSCI)、归一化植被指数(NDVI)、监督分类和坡度分级相结合的方法提取生物结皮,发现苔藓结皮的像元面积为0.72×104km2,占研究区总面积的6.43%。
Using the typical hyperspectral data and TM remote sensing images, the biological crusts dominated by moss crusts in the exuberant growth period (July-September) of Mu Us Sandland were studied. The results showed that: 1, the moss crust had similar trend of spectral curve with that of the green plant in the growth stage. The red edge parameters showed that the red edge, red edge width and red edge area were significantly different In the near infrared region, the reflectance of moss crusts was much lower than that of green plants. There was no obvious 553 nm reflection peak on moss crusts. The low-coverage moss crust (33%), algal crusts and vegetation litter The entire band spectral curve is relatively close, compared with the bare sand, the three reflectances are low. Based on the TM images, the biological crusts were extracted by BSCI, supervised classification and slope grade. The pixel area of moss crust was 0.72 × 104km2, Accounting for 6.43% of the total area of the study area.