Hemispherical photographic method for improving seasonal variation measurement precision of leaf area index (LAI)
A technology of hemispherical photography and leaf area index, which is applied in the field of forest ecology, can solve the problems of low accuracy of LAI value and measurement error in seasonal dynamic changes of forest ecosystems, and achieve low negative impact on the ecological environment, efficient seasonal changes, and reliable data Guaranteed effect
Active Publication Date: 2015-02-18
NORTHEAST FORESTRY UNIVERSITY
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[0003] The purpose of the present invention is to solve the problem that the existing hemispherical photography method has measurement errors due to the limitations of the optical instrument itself, and the LAI value of the detected seasonal dynamic change of the forest ecosystem has a low accuracy rate.
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[0015] The specific embodiment of the present invention is: a method for improving the accuracy of hemispherical photography to measure the seasonal variation of leaf area index, comprising:
[0016] The effective LAI value is measured by hemispheric photography, which is recorded as x;
[0017] Build an empirical model y=ax b ;
[0018] Corrected LAI values were calculated based on empirical models.
[0019] The range of a value of the coniferous forest is: 0.9448-1.1477, and the range of b value is: 1.9955-2.0693;
[0020] The range of a value of the broad-leaved forest is: 1.6988-3.034, and the range of b value is: 0.6061-1.1644;
[0021] The a value range of the coniferous broadleaf mixed forest is: 0.3468-1.6577, and the b value range is: 1.8986-3.3467.
[0022] In the coniferous and broadleaved mixed forest, coniferous trees and broadleaved trees are arranged at intervals.
[0023] Utilize hemispheric photography to determine the effective LAI value, including the...
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The invention provides a hemispherical photographic method for improving the seasonal variation measurement precision of the leaf area index (LAI) and relates to a method for improving the measurement precision of the leaf area index. The method aims at solving the problems that the existing hemispherical photographic method has measurement error caused by instrument limitation and the detection accuracy rate of the seasonal dynamic variation LAI of a forest ecological system is low. An empirical model is constructed to obtain the correction value of the measurement value obtained by the hemispherical photographic method, wherein the empirical model is that y is equal to axb, y is LAI correction values of all forest types in leaf growing period, leaf stationary phase and leaf withering and falling period, and x is LAI value measured by the hemispherical photographic method. The method has low negative effect on the ecological environment and the data accuracy can be improved remarkably.
Description
technical field [0001] The invention relates to a method for improving the accuracy of measuring leaf area index, in particular to a method for improving the accuracy of hemispheric photography for measuring the seasonal variation of leaf area index, and belongs to the technical field of forest ecology. Background technique [0002] Leaf area index (LAI) is an important parameter to quantify the structural characteristics of vegetation canopy. Accurately measuring the seasonal variation of LAI is important for understanding the seasonality of many forest physiological and ecological processes (such as photosynthesis, transpiration, and canopy interception of precipitation, etc.). Variability is critical and, moreover, one of the most important indicators for predicting stand growth. With the development of science and technology, the use of optical instruments to monitor the dynamic changes of forest ecosystem LAI has received widespread attention, mainly because of its conv...
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CPCG01C11/00
Inventor 刘志理金光泽王传宽王兴昌戚玉娇
Owner NORTHEAST FORESTRY UNIVERSITY