油松作为我国北方地区典型的森林植被类型,研究辐射能量在其冠层中的分配、收支及传输,是构建森林冠层辐射传输模型和生态过程模型的理论基础,对阐明森林植被群落中能量流动和物质循环机理具有重要意义。基于贺兰山生态站油松林通量塔...油松作为我国北方地区典型的森林植被类型,研究辐射能量在其冠层中的分配、收支及传输,是构建森林冠层辐射传输模型和生态过程模型的理论基础,对阐明森林植被群落中能量流动和物质循环机理具有重要意义。基于贺兰山生态站油松林通量塔定位观测获取的上、下行长短波辐射、光合有效辐射(photosynthetically active radiation,PAR)以及气象数据,分析2021年4—9月不同天气和季节条件下油松林冠层的辐射能量截获及传输特征。结果表明:(1)晴天条件下太阳总辐射的日变化表现为光滑的“单峰”曲线,但多云条件下则呈现不规则的“多峰”曲线,且减弱48.3%的太阳总辐射能量到达冠层顶部。(2)太阳总辐射以下行短波辐射为主,晴天的上行短波辐射日变化虽也呈“单峰”形态,但仅占下行短波辐射的8.1%,上行和下行长波辐射随昼夜交替略有波动。(3)太阳短波辐射的季节动态特征表明,上行和下行短波辐射在6月最高,而上行和下行长波辐射在7月最高。(4)在冠层上方(25 m处)呈规则“单峰”形态的PAR日动态曲线,经过冠层截获和传输作用后,在冠层下方(7 m处)变为不规则曲线;PAR的透过率为32.2%~53.9%,透过率在6月达到最高。(5)4-9月生长季短波反射率为7.8%~8.8%,而地表长波辐射收支比为0.73~0.80。结果显示,贺兰山油松林冠层对辐射能量有明显的截获作用,其辐射传输在不同天气条件和不同季节表现出较大的差异。展开更多
The use of unmanned aerial vehicles(UAV)for forest monitoring has grown significantly in recent years,providing information with high spatial resolution and temporal versatility.UAV with multispectral sensors allow th...The use of unmanned aerial vehicles(UAV)for forest monitoring has grown significantly in recent years,providing information with high spatial resolution and temporal versatility.UAV with multispectral sensors allow the use of indexes such as the normalized difference vegetation index(NDVI),which determines the vigor,physiological stress and photo synthetic activity of vegetation.This study aimed to analyze the spectral responses and variations of NDVI in tree crowns,as well as their correlation with climatic factors over the course of one year.The study area encompassed a 1.6-ha site in Durango,Mexico,where Pinus cembroides,Pinus engelmannii,and Quercus grisea coexist.Multispectral images were acquired with UAV and information on meteorological variables was obtained from NASA/POWER database.An ANOVA explored possible differences in NDVI among the three species.Pearson correlation was performed to identify the linear relationship between NDVI and meteorological variables.Significant differences in NDVI values were found at the genus level(Pinus and Quercus),possibly related to the physiological features of the species and their phenology.Quercus grisea had the lowest NDVI values throughout the year which may be attributed to its sensitivity to relative humidity and temperatures.Although the use of UAV with a multispectral sensor for NDVI monitoring allowed genera differentiation,in more complex forest analyses hyperspectral and LiDAR sensors should be integrated,as well other vegetation indexes be considered.展开更多
文摘油松作为我国北方地区典型的森林植被类型,研究辐射能量在其冠层中的分配、收支及传输,是构建森林冠层辐射传输模型和生态过程模型的理论基础,对阐明森林植被群落中能量流动和物质循环机理具有重要意义。基于贺兰山生态站油松林通量塔定位观测获取的上、下行长短波辐射、光合有效辐射(photosynthetically active radiation,PAR)以及气象数据,分析2021年4—9月不同天气和季节条件下油松林冠层的辐射能量截获及传输特征。结果表明:(1)晴天条件下太阳总辐射的日变化表现为光滑的“单峰”曲线,但多云条件下则呈现不规则的“多峰”曲线,且减弱48.3%的太阳总辐射能量到达冠层顶部。(2)太阳总辐射以下行短波辐射为主,晴天的上行短波辐射日变化虽也呈“单峰”形态,但仅占下行短波辐射的8.1%,上行和下行长波辐射随昼夜交替略有波动。(3)太阳短波辐射的季节动态特征表明,上行和下行短波辐射在6月最高,而上行和下行长波辐射在7月最高。(4)在冠层上方(25 m处)呈规则“单峰”形态的PAR日动态曲线,经过冠层截获和传输作用后,在冠层下方(7 m处)变为不规则曲线;PAR的透过率为32.2%~53.9%,透过率在6月达到最高。(5)4-9月生长季短波反射率为7.8%~8.8%,而地表长波辐射收支比为0.73~0.80。结果显示,贺兰山油松林冠层对辐射能量有明显的截获作用,其辐射传输在不同天气条件和不同季节表现出较大的差异。
基金supported by the National Council of Science and Technology of Mexico(CONACyT),which provided financial support through scholarships for postgraduate studies to J.L.G.S.(815176)and M.R.C.(507523)。
文摘The use of unmanned aerial vehicles(UAV)for forest monitoring has grown significantly in recent years,providing information with high spatial resolution and temporal versatility.UAV with multispectral sensors allow the use of indexes such as the normalized difference vegetation index(NDVI),which determines the vigor,physiological stress and photo synthetic activity of vegetation.This study aimed to analyze the spectral responses and variations of NDVI in tree crowns,as well as their correlation with climatic factors over the course of one year.The study area encompassed a 1.6-ha site in Durango,Mexico,where Pinus cembroides,Pinus engelmannii,and Quercus grisea coexist.Multispectral images were acquired with UAV and information on meteorological variables was obtained from NASA/POWER database.An ANOVA explored possible differences in NDVI among the three species.Pearson correlation was performed to identify the linear relationship between NDVI and meteorological variables.Significant differences in NDVI values were found at the genus level(Pinus and Quercus),possibly related to the physiological features of the species and their phenology.Quercus grisea had the lowest NDVI values throughout the year which may be attributed to its sensitivity to relative humidity and temperatures.Although the use of UAV with a multispectral sensor for NDVI monitoring allowed genera differentiation,in more complex forest analyses hyperspectral and LiDAR sensors should be integrated,as well other vegetation indexes be considered.
