A prediction model of apple leaf nitrogen content based on ground imaging spectroscopy was established to rapidly and nondestructively detect nitrogen content in apple leaves.SOC710VP hyperspectral imager was used to ...A prediction model of apple leaf nitrogen content based on ground imaging spectroscopy was established to rapidly and nondestructively detect nitrogen content in apple leaves.SOC710VP hyperspectral imager was used to obtain the imaging spectral information of apple leaves,and the average spectral curve of interest region was extracted.The study is to analyze the characteristics of imaging spectral curves of apple leaves with different nitrogen content.On the basis of the SG smoothing and first derivative pretreatment of the spectral curve,the maximum sensitive band with nitrogen content is screened and the spectral parameters are constructed.Three modeling methods of BP,SVM and RF were used to establish the prediction model of nitrogen content in apple leaves.The results showed that in the visible range,the nitrogen content of apple leaves was negatively correlated with the reflectance of the spectral curve,and was most obvious in the green range.The R2 of BP,SVM and RF of apple leaf nitrogen content prediction model were 0.7283,0.8128,0.9086,RMSE were 0.9359,0.7365,0.5368,the R2 of test model were 0.6260,0.7294,0.6512,RMSE were 0.9460,0.7350,0.9024.Comparing the prediction results of the three models,the optimal prediction model is SVM model,which can well predict the nitrogen content of apple leaves.展开更多
As the largest sub-basin of the middle reaches of the Yellow River with an obvious decreasing trend in annual runoff in recent years,the Weihe River basin is a significant region with regard to the protection and impr...As the largest sub-basin of the middle reaches of the Yellow River with an obvious decreasing trend in annual runoff in recent years,the Weihe River basin is a significant region with regard to the protection and improvement of the environment in West China.Evapotranspiration(ET)is the loss of water from the Earth’s surface to the atmosphere and plays an important role in the regional water cycle,especially when considering water resource shortages.In this study,through analyzing the grid precipitation data after interpolation from 39 meteorological stations in and around the Weihe River basin from 1981 to 2011,certain periods during 1987,1993,1999,2001,2002 and 2009 with similar precipitation characteristics had been chosen for estimating the ET in the Weihe River basin.To illustrate ET’s influence on the water budget,these estimations are calculated based on an improved Penman-Monteith equation as well as remote sensing data and meteorological data.The results show that:(1)the annual ET in the Weihe River basin ranged from 350mm to 400mm in 1987,1993,1999,2001,2002 and 2009,accounting for more than 70%of the corresponding annual precipitation.There is a definite increasing trend in different decades that is primarily distributed during the summer.(2)The spatial distribution patterns of the ET in the six years mentioned area unique set,and the years are roughly identical with more than 500mm in the middle and lower reaches of the Weihe River in the southeastern region and less than 400mm in upper reaches of the Jinghe River in the northwestern area.(3)At the single-point scale,the coefficient of determination(R2)is 0.618 compared to the eddy correlation measurements in 2009 at the Changwu site,showing good agreement between the estimated ET and the observed ET.At the basin scale,the model-estimated ET is slightly lower than the actual ET with regard to the surface water budget.Additionally,the estimated ET in 2001,2002 and 2009 is close to the MODIS ET product.(4)For similar precipitation conditions,the regional amount of water shows a decreasing tendency with increasing ET,which may result from the rise in NDVI and improvements in vegetation coverage caused by human activities.This research suggests the influence of ET on water change at the basin level,which can also explain the decreasing runoff and can provide necessary information for improved water resource management.展开更多
Estimating an apple tree canopy nitrogen contents using hyperspectral techniques is important in theoretical and realistic significance for fertilization and management.Taking 80 Fuji apple trees at the early fruiting...Estimating an apple tree canopy nitrogen contents using hyperspectral techniques is important in theoretical and realistic significance for fertilization and management.Taking 80 Fuji apple trees at the early fruiting stage as the research objects,the hyperspectral characteristics of the apple canopy were analyzed systematically.The apple canopy hyperspectral and the canopy nitrogen contents were measured respectively.The canopy hyperspectral characteristics under different nitrogen contents were analyzed and selected the sensitive wave bands.The apple canopy nitrogen content monitoring models were established by using multiple regression method,robust regression and BP neural network method.The results showed that the canopy hyperspectral reflectance had obvious differences under different nitrogen contents.The sensitive bands concentrate on 724~1136 nm.Estimation models based on hyperspectral indices are not ideal.Models based on robust regression(M regression)and BP neural network are better than multiple statistical model,and the accuracy of the BP neural network monitoring model is the best.The results of the study provide a certain reference for estimating apple nutrition using hyperspectral technology.展开更多
The Microwave Humidity and Temperature Sounder(MWHTS)is the main payload of FengYun 3D(FY-3D),designed for atmospheric humidity and temperature sounding,and also for monitoring severe weather systems such as typhoons ...The Microwave Humidity and Temperature Sounder(MWHTS)is the main payload of FengYun 3D(FY-3D),designed for atmospheric humidity and temperature sounding,and also for monitoring severe weather systems such as typhoons and rainstorms which will be launched in 2016.Before the launch of MWHTS,a series of experiments will be conducted in normal environment and a thermal/vacuum(T/V)chamber to determine radiometric characteristics of each channel,which are of very importance before the launch.In this paper,design and component description,as well as technical specifications and test results for RF and IF,will be provided.Then T/V calibration results,such as bandwidth correction,nonlinear error,calibration accuracy and sensitivity for all channels.展开更多
The apple orchard in Qixia City, Yantai City, Shandong Province was used as the research area. The nitrogen content inversion of apple canopy was studied by using the satellite remote sensing images of GF-1. On the ba...The apple orchard in Qixia City, Yantai City, Shandong Province was used as the research area. The nitrogen content inversion of apple canopy was studied by using the satellite remote sensing images of GF-1. On the basis of GF-1 satellite multispectral image preprocessing, vegetation index was extracted by band math. The nitrogen sensitive vegetation index of apple canopy was selected by correlation analysis of nitrogen content in apple canopy. The best inversion model for the nitrogen content of apple canopy was selected by establishing the regression model of univariate and multivariate factors. The nitrogen content of the canopy of apple orchard in the study area was inverted in space. The results showed that the 6 vegetation indices of RVI, NDVI, EVI, VARI, NPCI and NRI were better correlated with nitrogen content in the vegetation index based on GF-1 satellite multispectral imaging. The best inversion model of nitrogen content in apple canopy layer is the multivariate stepwise regression (MSR) model: Nc = 35.74– 41.978^*NPCI-10.78^*NDVI. The R^2 and RMSE of the model was 0.69 and 1.07. The spatial inversion of nitrogen content in apple orchard canopy was obtained. This study provided theoretical basis and technical support for large-area rapid monitoring of regional fruit tree nutrients.展开更多
The nutrient inversion model of apple leaves was established by spectral analysis technology to provide technical support for the fine management of apple trees.In Shuangquan Town,Changqing District,Jinan City,Shandon...The nutrient inversion model of apple leaves was established by spectral analysis technology to provide technical support for the fine management of apple trees.In Shuangquan Town,Changqing District,Jinan City,Shandong Province,the Fuji apple trees with stopping period of spring shoots were taken as research objects.The spectral reflectance and nitrogen content of apple leaves were measured by ASD Field Spec 4 portable ground object spectrometer.Analyzed the correlation between leaf nitrogen content and spectral reflectance.The sensitive wavelengths with high correlation coefficient were select by fractional differential algorithm,and the optimal vegetation index was constructed and screened out.Partial Least Square Regression(PLSR),Support Vector Machine(SVM)and Random Forests(RF)method were used to construct an inversion model of leaf nitrogen content.The results show that the RF model based on fractional differential second-order treatment is the best inversion model for the nitrogen content of leaves during stopping period of spring shoots.The modeling accuracy determination coefficient R2 reached 0.891,RMSE was 0.0841,and RPD was 2.1396.The determination coefficient R2 of the fitting results of the verification set was 0.617,RMSE was 0.1251,and RPD was 1.7105.The inversion model established by RF method is effective in monitoring the nitrogen content in apple leaves,which provides a theoretical basis for monitoring the growth of apple by hyperspectral technology.展开更多
基金the National Natural Science Foundation of China(41671346)Funds of Shandong“Double Tops”Program(SYL2017XTTD02).
文摘A prediction model of apple leaf nitrogen content based on ground imaging spectroscopy was established to rapidly and nondestructively detect nitrogen content in apple leaves.SOC710VP hyperspectral imager was used to obtain the imaging spectral information of apple leaves,and the average spectral curve of interest region was extracted.The study is to analyze the characteristics of imaging spectral curves of apple leaves with different nitrogen content.On the basis of the SG smoothing and first derivative pretreatment of the spectral curve,the maximum sensitive band with nitrogen content is screened and the spectral parameters are constructed.Three modeling methods of BP,SVM and RF were used to establish the prediction model of nitrogen content in apple leaves.The results showed that in the visible range,the nitrogen content of apple leaves was negatively correlated with the reflectance of the spectral curve,and was most obvious in the green range.The R2 of BP,SVM and RF of apple leaf nitrogen content prediction model were 0.7283,0.8128,0.9086,RMSE were 0.9359,0.7365,0.5368,the R2 of test model were 0.6260,0.7294,0.6512,RMSE were 0.9460,0.7350,0.9024.Comparing the prediction results of the three models,the optimal prediction model is SVM model,which can well predict the nitrogen content of apple leaves.
文摘As the largest sub-basin of the middle reaches of the Yellow River with an obvious decreasing trend in annual runoff in recent years,the Weihe River basin is a significant region with regard to the protection and improvement of the environment in West China.Evapotranspiration(ET)is the loss of water from the Earth’s surface to the atmosphere and plays an important role in the regional water cycle,especially when considering water resource shortages.In this study,through analyzing the grid precipitation data after interpolation from 39 meteorological stations in and around the Weihe River basin from 1981 to 2011,certain periods during 1987,1993,1999,2001,2002 and 2009 with similar precipitation characteristics had been chosen for estimating the ET in the Weihe River basin.To illustrate ET’s influence on the water budget,these estimations are calculated based on an improved Penman-Monteith equation as well as remote sensing data and meteorological data.The results show that:(1)the annual ET in the Weihe River basin ranged from 350mm to 400mm in 1987,1993,1999,2001,2002 and 2009,accounting for more than 70%of the corresponding annual precipitation.There is a definite increasing trend in different decades that is primarily distributed during the summer.(2)The spatial distribution patterns of the ET in the six years mentioned area unique set,and the years are roughly identical with more than 500mm in the middle and lower reaches of the Weihe River in the southeastern region and less than 400mm in upper reaches of the Jinghe River in the northwestern area.(3)At the single-point scale,the coefficient of determination(R2)is 0.618 compared to the eddy correlation measurements in 2009 at the Changwu site,showing good agreement between the estimated ET and the observed ET.At the basin scale,the model-estimated ET is slightly lower than the actual ET with regard to the surface water budget.Additionally,the estimated ET in 2001,2002 and 2009 is close to the MODIS ET product.(4)For similar precipitation conditions,the regional amount of water shows a decreasing tendency with increasing ET,which may result from the rise in NDVI and improvements in vegetation coverage caused by human activities.This research suggests the influence of ET on water change at the basin level,which can also explain the decreasing runoff and can provide necessary information for improved water resource management.
文摘Estimating an apple tree canopy nitrogen contents using hyperspectral techniques is important in theoretical and realistic significance for fertilization and management.Taking 80 Fuji apple trees at the early fruiting stage as the research objects,the hyperspectral characteristics of the apple canopy were analyzed systematically.The apple canopy hyperspectral and the canopy nitrogen contents were measured respectively.The canopy hyperspectral characteristics under different nitrogen contents were analyzed and selected the sensitive wave bands.The apple canopy nitrogen content monitoring models were established by using multiple regression method,robust regression and BP neural network method.The results showed that the canopy hyperspectral reflectance had obvious differences under different nitrogen contents.The sensitive bands concentrate on 724~1136 nm.Estimation models based on hyperspectral indices are not ideal.Models based on robust regression(M regression)and BP neural network are better than multiple statistical model,and the accuracy of the BP neural network monitoring model is the best.The results of the study provide a certain reference for estimating apple nutrition using hyperspectral technology.
文摘The Microwave Humidity and Temperature Sounder(MWHTS)is the main payload of FengYun 3D(FY-3D),designed for atmospheric humidity and temperature sounding,and also for monitoring severe weather systems such as typhoons and rainstorms which will be launched in 2016.Before the launch of MWHTS,a series of experiments will be conducted in normal environment and a thermal/vacuum(T/V)chamber to determine radiometric characteristics of each channel,which are of very importance before the launch.In this paper,design and component description,as well as technical specifications and test results for RF and IF,will be provided.Then T/V calibration results,such as bandwidth correction,nonlinear error,calibration accuracy and sensitivity for all channels.
基金the National Natural Science Foundation of China(41671346)National Key Research and Development Program of China (2017YFE0122500)+2 种基金the Taishan Scholar Assistance Program from Shandong Provincial GovernmentFunds of Shandong “Double Tops” Program(SYL2017XTTD02)Shandong major scientific and technological innovation project: Research demonstration and extension of orchard irrigation and fertilization in accurate management(2018CXGC0209).
文摘The apple orchard in Qixia City, Yantai City, Shandong Province was used as the research area. The nitrogen content inversion of apple canopy was studied by using the satellite remote sensing images of GF-1. On the basis of GF-1 satellite multispectral image preprocessing, vegetation index was extracted by band math. The nitrogen sensitive vegetation index of apple canopy was selected by correlation analysis of nitrogen content in apple canopy. The best inversion model for the nitrogen content of apple canopy was selected by establishing the regression model of univariate and multivariate factors. The nitrogen content of the canopy of apple orchard in the study area was inverted in space. The results showed that the 6 vegetation indices of RVI, NDVI, EVI, VARI, NPCI and NRI were better correlated with nitrogen content in the vegetation index based on GF-1 satellite multispectral imaging. The best inversion model of nitrogen content in apple canopy layer is the multivariate stepwise regression (MSR) model: Nc = 35.74– 41.978^*NPCI-10.78^*NDVI. The R^2 and RMSE of the model was 0.69 and 1.07. The spatial inversion of nitrogen content in apple orchard canopy was obtained. This study provided theoretical basis and technical support for large-area rapid monitoring of regional fruit tree nutrients.
基金This paper was supported by the National Natural Science Foundation of China(41671346)the National Key Research and Development Program of China(2017YFE0122500)+1 种基金Shandong Major Scientific and Technological Innovation Project(2018CXGC0209)the Taishan Scholar Assistance Program from Shandong Provincial Government,Funds of Shandong“Double Tops”Program(SYL2017XTTD02).
文摘The nutrient inversion model of apple leaves was established by spectral analysis technology to provide technical support for the fine management of apple trees.In Shuangquan Town,Changqing District,Jinan City,Shandong Province,the Fuji apple trees with stopping period of spring shoots were taken as research objects.The spectral reflectance and nitrogen content of apple leaves were measured by ASD Field Spec 4 portable ground object spectrometer.Analyzed the correlation between leaf nitrogen content and spectral reflectance.The sensitive wavelengths with high correlation coefficient were select by fractional differential algorithm,and the optimal vegetation index was constructed and screened out.Partial Least Square Regression(PLSR),Support Vector Machine(SVM)and Random Forests(RF)method were used to construct an inversion model of leaf nitrogen content.The results show that the RF model based on fractional differential second-order treatment is the best inversion model for the nitrogen content of leaves during stopping period of spring shoots.The modeling accuracy determination coefficient R2 reached 0.891,RMSE was 0.0841,and RPD was 2.1396.The determination coefficient R2 of the fitting results of the verification set was 0.617,RMSE was 0.1251,and RPD was 1.7105.The inversion model established by RF method is effective in monitoring the nitrogen content in apple leaves,which provides a theoretical basis for monitoring the growth of apple by hyperspectral technology.
