草业科学2024,Vol.41Issue(3) :588-598.DOI:10.11829/j.issn.1001-0629.2023-0091

低覆盖草地叶面积指数遥感估算方法

Estimation of grassland leaf area index by remote sensing under low-coverage conditions

张云峰 任鸿瑞
草业科学2024,Vol.41Issue(3) :588-598.DOI:10.11829/j.issn.1001-0629.2023-0091

低覆盖草地叶面积指数遥感估算方法

Estimation of grassland leaf area index by remote sensing under low-coverage conditions

张云峰 1任鸿瑞1
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作者信息

  • 1. 太原理工大学测绘科学与技术系, 山西太原 030024
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摘要

有效估算低覆盖草地叶面积指数(LAI),对监测低覆盖草地生长状况、优化完善草地管理具有重要意义.以往针对草地叶面积指数的研究大多集中于中高覆盖度草地,对低覆盖草地的研究相对较少.利用谷歌地球引擎(GEE),基于Landsat-8卫星数据提取所需特征变量,通过特征变量与叶面积指数的相关性及其在模型中的重要性进行特征优选,确定模型最佳变量个数,以此构建机器学习模型,探寻适合在低覆盖区草地估算叶面积指数的方法.结果显示,基于相关性特征优选的梯度提升回归树模型(r-GBRT)在低覆盖草地估算叶面积指数的效果较好,测试集的R2为0.686,均方根误差(RMSE)为0.101.结果表明,基于特征优选构建的机器学习模型在低覆盖条件下估算草地叶面积指数方面具有较好的应用价值.

Abstract

Accurately estimating the leaf area index (LAI) of low-coverage grasslands holds significant importance for monitoring their growth conditions and optimizing grassland management practices. Previous studies of LAI have primarily focused on grasslands with medium-to-high coverage, and relatively limited attention has been given to low-coverage grasslands. Leveraging Google Earth Engine (GEE), essential feature variables were extracted from Landsat-8 satellite data. Feature selection was performed based on the correlation of these variables with LAI values and their importance within the model, determining the optimal number of variables to construct a machine-learning model for estimating the LAI value in low-coverage grassland areas. The results indicated that the gradient boosting regression tree model selected based on feature correlation performed well in estimating the LAI value in low-coverage grasslands, with a test set coefficient of determination (R2) of 0.686 and a root mean square error of 0.101. These findings suggest that machine-learning models constructed using feature selection have significant practical utility in estimating LAI values in low-coverage grassland conditions.

关键词

叶面积指数/低覆盖草地/机器学习/特征优选/随机森林/梯度提升回归树/遥感

Key words

leaf area index/low-cover grassland/machine learning/feature optimization/random forest/gradient boosting regression tree/remote sensing

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基金项目

山西省省筹资金资助留学回国人员科研项目(2022-055)

出版年

2024
草业科学
中国草原学会 兰州大学草地农业科技学院

草业科学

CSTPCDCSCD北大核心
影响因子:0.854
ISSN:1001-0629
参考文献量36
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