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生物土壤结皮(BSC)是由藻类、地衣、苔藓和土壤中微生物形成的一类有机复合体,是干旱荒漠地区主要的地表覆被类型。由于藻、地衣和苔藓呈非连续性斑块状分布,准确估算它们的盖度比较困难。传统的估算方法主要是样方法和遥感影像法,样方法在野外操作中虽然比较精确但是费时,遥感影像法虽然快速但是误差大。本文试图通过数码照相法获取BSC地表分布信息,然后利用最大似然监督分类法对苔藓结皮、地衣结皮和藻结皮盖度进行分类计算,并用野外原位调查进行验证。结果表明,本文采用的照相法与传统样方法的相关性达到了94.45%,照相法可以有效地用于BSC盖度的估算,提高了盖度估算的效率。
Biological soil crust (BSC) is an organic complex formed by algae, lichen, mosses and microorganisms in the soil. It is the main surface cover type in arid desert areas. As algae, lichen and mosses are non-contiguous patchy distribution, accurate estimation of their coverage is more difficult. The traditional estimation methods are mainly the sample method and the remote sensing image method. Although the sample method is more precise but time-consuming in the field operation, the remote sensing image method is fast but has a large error. This paper attempts to obtain the BSC surface distribution information by digital photography method, and then uses the method of maximum likelihood supervised classification to classify the moss crust, lichen crust and algal crust coverage, and verifies with the field investigation. The results show that the correlation between the photographic method and the traditional method is 94.45%. The photographic method can effectively estimate the BSC coverage and improve the efficiency of the coverage estimation.