摘要
草原地上生物量(AGB)是草原调查监测中的重要指标,是草原生态保护和资源合理利用的依据,对草原可持续发展与科学管理具有重要意义。本研究以广西兴安县热性灌草丛为研究对象,结合机载激光雷达数据与高分辨率多光谱卫星影像,利用2021年采集的89个实地样方调查数据,对草原AGB进行了遥感反演研究。结果表明,草层高度信息是草原AGB建模的重要指标。增强型植被指数(EVI)、比值植被指数(RVI)、归一化植被指数(NDVI)中EVI与AGB的相关系数最高(0.666),高度指标中平均草层高度(CHM_(mean))与AGB的相关系数最高(0.686),二者结合的指标中RVI×CHM_(mean)与AGB的相关系数最高(0.735)。模型精度验证结果显示,EVI模型中均方根误差(RMSE)最低,为292.047 g·m^(-2),CHM_(mean)模型中RMSE最低,为245.084 g·m^(-2),RVI×CHM_(mean)模型中RMSE最低为225.872 g·m^(-2)。结果说明机载激光雷达数据可以有效提取草层高度信息,尽管存在明显的低估现象,但在草原AGB研究中仍具有较大的应用潜力。
Grassland aboveground biomass(AGB)is an important indicator in grassland monitoring.It is an important index when designing strategies for the ecological protection and rational utilization of grassland resources.In addition,it is of great significance for the sustainable development and scientific management of grassland.In this study,shrub grassland in Xing’an County,Guangxi was the subject of the research,and data were obtained from airborne LiDAR data and high-resolution multispectral satellite images.The retrieval of grassland AGB was investigated using data collected from 89 field quadrats in 2021 and five basic regression models.The accuracy of different indicators and models was evaluated by root mean square error(RMSE),mean absolute error(MAE),and R-square values.It was found that grass height metrics were very important information for grassland AGB retrieval.We calculated correlation coefficients between pairs of indexes.In terms of vegetation indexes,the highest correlation coefficient was between the enhanced vegetation index(EVI)and AGB(0.666).In terms of vegetation height indexes,the highest correlation coefficient was between average grass height(CHM_(mean))and AGB(0.686).In terms of combined indexes,the highest correlation coefficient was between the ratio vegetation index(RVI)×CHM_(mean)and AGB(0.735).The accuracy and verification results showed that the minimum RMSE of the EVI models was 292.047 g·m^(-2),the minimum RMSE of CHM_(mean)models was 245.084 g·m^(-2),and the minimum RMSE of RVI×CHM_(mean)models was 225.872 g·m^(-2).Our results show that grass height information can be effectively extracted from airborne LiDAR data,and although there is an obvious underestimation,it still has great application potential in research on grassland AGB.
作者
许开宏
施招
马磊超
王平
陈昂
王兴
成明
肖粤新
王荣谭
XU Kai-hong;SHI Zhao;MA Lei-chao;WANG Ping;CHEN Ang;WANG Xing;CHENG Ming;XIAO Yue-xin;WANG Rong-tan(Changsha Natural Resources Comprehensive Survey Center,Director of China Geological Survey,Changsha 410699,China;Natural Resources Comprehensive Survey Command Center of China Geological Survey,Beijing 100055,China;School of Grassland Science,Beijing Forestry University,Beijing 100083,China)
出处
《草业学报》
CSCD
北大核心
2023年第5期40-49,共10页
Acta Prataculturae Sinica
基金
全国草原资源调查监测(长沙中心)(DD20211606)资助。
关键词
草原地上生物量
机载激光雷达
草层高度
高分辨率卫星影像
遥感反演模型
grassland aboveground biomass
airborne LiDAR
grass height
high-resolution satellite image
remotely sensed retrieval model
