Method of Extracting Vertical Distribution of Leaf Area Based on Hyperspectral and LiDAR

Abstract

The invention discloses a hyperspectrum and laser radar-based method for extracting vertical distribution of leaf area. The hyperspectrum and laser radar-based method mainly comprises the steps of 1, classifying point cloud data of an airborne laser radar, and extracting vegetation structure parameters; 2, acquiring distribution of region leaf area indexes by virtue of a geometrical optical model on the basis of hyperspectrum data and the extracted vegetation structure parameters; 3, calculating the percentage of vegetation laser points above the ground on each height layer, thus obtaining a height profile of a corresponding vegetation canopy; and 4, on the basis of extracting the vegetation leaf area indexes and the height profile of the canopy, distributing the vegetation leaf area indexes according to the height profile of the canopy to obtain a vegetation leaf area index of each layer and vegetation leaf area indexes accumulated along with the height. According to the hyperspectrum and laser radar-based method, horizontal information of the hyperspectrum data and response of the laser radar to vegetation height information are comprehensively utilized, the vertical distribution of the region leaf area indexes is extracted, and more accurate parameter input is provided for a physical model-based vegetation radiation transmission model.

Description

technical field [0001] The invention belongs to the technical field of calculation and evaluation of ecological vegetation parameters, and in particular relates to a method for extracting vertical distribution of leaf area index. Background technique [0002] Leaf area index (LAI) is an important vegetation parameter required by some related ecological processes. Its vertical distribution affects the photosynthetically active radiation, photosynthesis and evapotranspiration of vegetation, and it is also one of the important measures of forest carbon budget. Therefore, its accurate assessment plays an important role in both evapotranspiration and net primary productivity assessment. [0003] In order to clearly describe the vertical structure of the vegetation canopy, it is very important to study the leaf height profile or canopy height profile (Canopy Height Profile, CHP), which arouses people's interest in the vertical distribution of leaf area index. Some researchers stu...

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Problems solved by technology

In the past, there were mainly two ways to evaluate the vertical distribution of leaf area: leaf area collection and model indirect evaluation. The direct collection method usually involves the problem of destroying the canopy and time-consuming collection, and it is also difficult to collect enough samples in a large experimental area. Difficultly, this method is not suitable for long-term monitoring of the spatial and temporal dynamics of leaf area; the measurement accuracy of the latter method is often limited by the spatial distribution of leaves and lighting conditions

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