青藏工程走廊多年冻土段植被覆盖度动态快速测量方法研究

植被盖度的变化动态可以在一定程度上反映气候环境的变化,是表征生态环境变化特征的一个直接的主导性指标, 对其测量的准确性可以在很大程度上影响对生态环境变化预报的精度。本研究利用普通照相法结合数字图像处理技术对青藏铁路和青藏公路沿线多年冻土段高寒植被的盖度进行调查研究, 并与传统的目估法、目视解译法进行了对比, 在此基础上对青藏工程走廊多年冻土段植被盖度进行简单评估。结果表明, 无论是青藏铁路沿线还是青藏公路沿线, 用模型处理法和目视解译法得到的植被盖度结果之间相关系数都最高,分别为R2=0.96和R2=0.97;比较结果表明, 用模型处理法比用简单目测法获得的植被盖度更接近实际覆盖度, 说明模型处理法适合应用于青藏工程走廊多年冻土段植被覆盖度动态快速测量。

A Test on the Computing-model-aided Photograph-Reading Method for Conveniently Measuring the Vegetation Cover in the Permafrost Area along the Qinghai-Tibet Engineering Corridor

Vegetation cover may vary with climate change in some degree. The varitioan of vegetation cover was therefore regarded as a primary index for indicating ecological enviornmental change, and the accuracy of the measurement on the vegetation cover change is essential to forecasting ecological environmental changes resonably. By taking photographs of the vegetation in the permafrost area along the Qinghai-Tibet Engineering Corridor, then reading and analyzing the photos with a computing model, we achieved the caverage of the vegetation. At the same time when the photos were taken, we estimated the coverage by simple eye observing and cross eye observing. The result of comparison among the three methods showed that the coverage gotten by the computing-model aided method could be linearly regressed to that by cross eye observing mehtod (R2≥0.96), suggesting that the computing-model-aided photograph-reading method could be employed to monitor the variation of the vegetation in the permafrost area along the Qinghai-Tibet Engineering Corridor reliably and conviniently, sopposed the coverage obtained with the cross eye observing method was the actual coverage.