基于光谱特征的高寒山区森林生态系统水源涵养分布反演研究被引量：1

Research on Inversion of Water Conservation Distribution of Forest Ecosystem in Alpine Mountain Based on Spectral Features

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摘要森林生态系统水源涵养具有调节气候,维持生态水平衡等生态功能。青藏高原作为高寒地区,由于其高海拔,环境恶劣的特征,无法实地人工观测水源涵养量。为更好地获取高寒地区的水源涵养量,通过遥感反演的方式得到特定地区的水源涵养价值量。以林芝巴宜区为研究区,研究区内林芝云杉、高山栎、高山松和雪层杜鹃四种植被为主要树种,遥感影像无法直接获得水源涵养信息,但可以通过构建植被叶片光谱信息与水源涵养量之间的定量关系来反演水源涵养价值量。研究不同植被与水源涵养量的定量关系,每种植被采集10个样点共1000个叶片样本和水源涵养数据,利用ASD光谱仪获取高光谱数据,通过相关性选取拟合参数,构建水源涵养回归模型。利用Sentinel-2遥感影像反演研究区内植被的水源涵养分布,并对反演结果进行验证。结果表明,四类植被叶片的反射光谱,均呈现出相似的规律性,在可见光波段差异不明显,近红外到中红外波段呈现出明显四个水吸收带,在红光到近红外波段(700~1400 nm)反射率最高。光谱反射率大小表现为高山栎>高山松>林芝云杉≈雪层杜鹃。通过实验获取植被冠层截流量、枯落物持水量和土壤含水量,三者之和代表植被的水源涵养量,分析植被的光谱特征与水源涵养量的关系,并通过Pearson系数评价波段参数与水源涵养的定量化关系,确定R_(540),R_(1950),NDWI和NDVI四个参数与水源涵养量显著相关。根据上述参数与四类植被的水源涵养量构建水源涵养回归模型,并通过模型反演研究区内植被水源涵养量,检验模拟精度,整体反演精度R^(2)大于0.7,RMSE基本小于10,说明预测模型反演效果较好,模型可有效估算森林生态系统的水源涵养量。 Water conservation in forest ecosystems has ecological functions such as regulating climate and maintaining ecological water balance.As an alpine region,the Qinghai-Tibet Plateau cannot manually observe water conservation on the spot due to its high altitude and harsh environment.In order to better obtain water conservation in alpine regions,remote sensing technology is introduced,and the value of water conservation in a specific area is obtained through remote sensing inversion.This study takes Nyingchi Bayi District as the study area.The study area uses four types of vegetation:Nyingchi Spruce,Alpine Quercus,Alpine Pine and Snow Rhododendron as the main tree species.Remote sensing images cannot directly obtain water conservation information,but the value of water conservation can be inverted by constructing a quantitative relationship between vegetation leaf spectral information and water conservation.To study the quantitative relationship between different vegetations and water conservation,collect 1000 leaf samples and water conservation data from 10 sampling points for each vegetation,use ASD spectrometer to obtain hyperspectral data,select fitting parameters through correlation,and build a regression model of water conservation.The Sentinel-2 remote sensing image was used to invert the water conservation distribution of vegetation in the study area,and the inversion results were verified.The results show that the reflectance spectra of the four types of vegetation leave all show similar regularities.The difference is not obvious in the visible light band,and there are four obvious water absorption bands in the near-infrared to the mid-infrared band(700~1400 nm),and the reflectivity in the red to near-infrared band highest.The spectral reflectance showed the order of Alpine Quercus>Alpine Pine>Lingzhi Spruce≈Snow Rhododendron.Through experiments,the vegetation canopy interception,litter water holding capacity and soil water content are obtained.The sum of the three represents the water conservation capacit

作者牛腾卢杰于佳鑫武英达龙芊芊于强 NIU Teng;LU Jie;YU Jia-xin;WU Ying-da;LONG Qian-qian;YU Qiang(Institute of Tibet Plateau Ecology,Tibet Agriculture&Animal Husbandry University,Linzhi 860000,China;Key Laboratory of Forest Ecology in Tibet Plateau(Tibet Agriculture&Animal Husbandry University),Ministry of Education,Linzhi 860000,China;Beijing Key Laboratory of Precision Forestry,Beijing Forestry University,Beijing100083,China;Hutuohe State-Owned Forest Farm of Shijiazhuang Forestry Bureau,Shijiazhuang050000,China;Forest and Grassland Fire Fighting Research of China Fire and Rescue Institute,Beijing 102202,China)

机构地区西藏农牧学院高原生态研究所西藏高原森林生态教育部重点实验室北京林业大学精准林业北京重点实验室石家庄市林业局滹沱河国有林场中国消防救援学院森林草原防灭火研究中心