Abstract

Mountain steppe has important production value and ecological function. The chlorophyll content is a critical biochemical parameter of steppe. This study aims at exploring effective spectral parameters for estimating the chlorophyll content in mountain steppe using in situ hyperspectral measurements. The study area is located on the northern slope of Tianshan Mountains with complex terrain and sparse vegetation. The canopy hyperspectral data and leaf chlorophyll content and canopy chlorophyll content data were measured from 101 samples. The empirical models were constructed based on nine vegetation indices and three red-edge parameters. The results showed that the red-edge magnitude, red-edge area, Second Modified Chlorophyll Absorption Ratio Index, Second Modified Chlorophyll Absorption Ratio Index/Second Optimized Soil-Adjusted Vegetation Index, Second Transformed Chlorophyll Absorption Ratio Index and Triangle Vegetation Index estimated canopy chlorophyll content satisfactorily. Leaf chlorophyll content of mountain steppe is not well estimated using canopy spectral parameters. The results revealed the specific vegetation indices and red-edge parameters for estimating vegetation biochemical parameters at canopy scale in mountain steppe using in situ hyperspectral measurements.

摘要

山地草原具有重要的生产价值和生态功能。叶绿素含量是草原的关键生化参数。这项研究的目的是探索有效频谱参数使用在山地草原估计叶绿素含量原位高光谱测量。研究区地处天山北坡，地形复杂，植被稀疏。冠层高光谱数据和叶片叶绿素含量和冠层叶绿素含量数据是从 101 个样品中测量的。经验模型是基于九个植被指数和三个红边参数构建的。结果表明，红边幅度、红边面积、二阶修正叶绿素吸收比指数、二阶修正叶绿素吸收比指数/二阶优化土壤调整植被指数、二阶叶绿素吸收比指数和三角植被指数估计冠层叶绿素内容令人满意。使用冠层光谱参数不能很好地估计山地草原的叶绿素含量。原位高光谱测量。