To upscale the genetic parameters of CERES-Rice in regional applications, Jiangsu Province, the second largest rice producing province in China, was taken as an example. The province was divided into four rice regions...To upscale the genetic parameters of CERES-Rice in regional applications, Jiangsu Province, the second largest rice producing province in China, was taken as an example. The province was divided into four rice regions with different rice variety types, and five to six sites in each region were selected. Then the eight genetic parameters of CERES-Rice, particularly the four parameters related to the yield, were modified and validated using the Trial and Error Method and the local statistical data of rice yield at a county level from 2001 to 2004, combined with the regional experiments of rice varieties in the province as well as the local meteorological and soil data （Method 1）. The simulated results of Method 1 were compared with those of other three traditional methods upscaling the genetic parameters, i.e., using one-site experimental data from a local representative rice variety （Method 2）, using local long-term rice yield data at a county level after deducting the trend yield due to progress of science and technology （Method 3）, and using rice yield data at a super scale, such as provincial, ecological zone, country or continent levels （Method 4）. The results showed that the best fitness was obtained by using the Method 1. The coefficients of correlation between the simulated yield and the statistical yield in the Method 1 were significant at 0.05 or 0.01 levels and the root mean squared error （RMSE） values were less than 9% for all the four rice regions. The method for upscaling the genetic parameters of CERES-Rice presented is not only valuable for the impact studies of climate change, but also favorable to provide a methodology for reference in crop model applications to the other regional studies.展开更多
Broadband response metamaterial absorber(MMA)remains a challenge among researchers.A nanostructured new zero-indexed metamaterial(ZIM)absorber is presented in this study,constructed with a hexagonal shape resonator fo...Broadband response metamaterial absorber(MMA)remains a challenge among researchers.A nanostructured new zero-indexed metamaterial(ZIM)absorber is presented in this study,constructed with a hexagonal shape resonator for optical region applications.The design consists of a resonator and dielectric layers made with tungsten and quartz(Fused).The proposed absorbent exhibits average absorption of more than 0.8972(89.72%)within the visible wavelength of 450–600 nm and nearly perfect absorption of 0.99(99%)at 461.61 nm.Based on computational analysis,the proposed absorber can be characterized as ZIM.The developments of ZIM absorbers have demonstrated plasmonic resonance characteristics and a perfect impedance match.The incidence obliquity in typically the range of 0◦–90◦both in TE and TM mode with maximum absorbance is more than 0.8972(∼89.72%),and up to 45◦angular stability is suitable for solar cell applications,like exploiting solar energy.The proposed structure prototype is designed and simulated by studying microwave technology numerical computer simulation(CST)tools.The finite integration technique(FIT)based simulator CST and finite element method(FEM)based simulator HFSS also helps validate the numerical data of the proposed ZIM absorber.The proposed MMA design is appropriate for substantial absorption,wide-angle stability,absolute invisible layers,magnetic resonance imaging(MRI),color images,and thermal imaging applications.展开更多
Compared to lake area and water level,lake storage capacity more intuitively reflects regional climate changes.In this study,we first derived lakebed elevation profiles for individual ICESat-2 tracks based on the unde...Compared to lake area and water level,lake storage capacity more intuitively reflects regional climate changes.In this study,we first derived lakebed elevation profiles for individual ICESat-2 tracks based on the underwater stratification of laser photons,then integrating all valid elevation tracks within the water body to interpolate the bathymetry.On this basis,we calculated the capacity and its time series directly,with the aid of lake boundaries and water levels obtained from optical imagery and CryoSat-2 data.Next,we also applied an empirical formula to estimate the water volume changes of Bangdag Co by combining the area and water levels from 2010 to 2023.Finally,we compared the results of Bangdag Co's water volume changes obtained from the two different methods and conducted a detailed analysis of their performance and regional applicability.The bathymetric map of Bangdag Co reveals a distinct spatial pattern,with the northeastern part significantly deeper(with a maximum depth of 35.27 m)and the southwestern part shallower.The average depth of the lake is 13.99 m.We further estimated that the lake storage capacity in November 2023 was 2.95 km^(3).Water volume changes estimated using the empirical formula were highly consistent with those derived from the lake storage capacity time series(from 2010 to 2023,the lake storage capacity increased by 1.04 km^(3)).Our comparison revealed that the empirical formula method reflects only changes in water volume.In contrast,while our method can accurately estimate lake storage capacity,it is constrained to shallow,clear,and elongated east-west lakes(e.g.,Ayakkum Lake).In summary,the ICESat-2 laser altimetry data,which do not rely on measured water depths,offer an essential complement to underwater topography detection and provide a novel perspective on lake volume estimation research.展开更多
Soil mineralized nitrogen(N)is a vital component of soil N supply capacity and an important N source for rice growth.Unveiling N mineralization(Nm)process characteristics and developing a simple and effective approach...Soil mineralized nitrogen(N)is a vital component of soil N supply capacity and an important N source for rice growth.Unveiling N mineralization(Nm)process characteristics and developing a simple and effective approach to evaluate soil Nm are imperative to guide N fertilizer application and enhance its efficiency in various paddy soils with different physicochemical properties.Soil properties are important driving factors contributing to soil Nm differences and must be considered to achieve effective N management.Nevertheless,discrepancies in Nm capacity and other key influencing factors remain uncertain.To address this knowledge gap,this study collected 52 paddy soil samples from Taihu Lake Basin,China,which possess vastly different physicochemical properties.The samples were subjected to a 112-d submerged anaerobic incubation experiment at a constant temperature to obtain the soil Nm characteristics.Reaction kinetics models,including one-pool exponential model,two-pool exponential model,and effective cumulative temperature model,were employed to compare characteristic differences between Nm potential(Nmp)and short-term accumulated mineralized N(Amn)processes in relation to soil physicochemical properties.Based on these relationships,simplified Nmp prediction methods for paddy soils were established.The results revealed that the Nmp values were 145.18,88.64,and 21.03 mg kg-1 in paddy soils with pH<6.50,6.50≤pH≤7.50,and pH>7.50,respectively.Significantly,short-term Amn at day 14 showed a good correlation(P<0.01)with Nmp(R2=0.94),indicating that the prevailing short-term incubation experiment is an acceptable marker for Nmp.Moreover,Nmp correlated well with the ultraviolet absorbance value at 260 nm based on NaHCO3 extraction(Na260),further streamlining the Nmp estimation method.The incorporation of easily obtainable soil properties,including pH,total N(TN),and the ratio of total organic carbon to TN(C/N),alongside Na260 for Nmp evaluation allowed the multiple regression model,Nmp=58.62×TN-23.18×pH+13.08×C/N+86.96×Na260,to achieve a high prediction accuracy(R2=0.95).The reliability of this prediction was further validated with published data of paddy soils in the same region and other rice regions,demonstrating the regional applicability and prospects of this model.This study underscored the roles of soil properties in Nm characteristics and mechanisms and established a site-specific prediction model based on rapid extractions and edaphic properties of paddy soils,paving the way for developing rapid and precise Nm prediction models.展开更多
This study used a 1.5-layer reduced-gravity numerical model to investigate the nonlinear dynamics of Kuroshio intrusion into the Luzon Strait.The model results suggested that both basin-scale wind curl and lateral fri...This study used a 1.5-layer reduced-gravity numerical model to investigate the nonlinear dynamics of Kuroshio intrusion into the Luzon Strait.The model results suggested that both basin-scale wind curl and lateral friction are the primary factors that control the transformation of the flow,although inertia also plays an important role.Using an idealized model,both the mechanism via which the flow pattern changes depending on the two primary factors and the occurrence of hysteresis were investigated.It was established that the transformation of the Kuroshio flow field between the four previously reported flow patterns(i.e.,leaping across,current looping,eddy shedding,and branch intruding) can be explained under a unified theoretical framework.A diagram is proposed to explain how the flow field transforms between the four patterns from a certain prior state when varying the values of the controlling factors.展开更多
With the advent of very high-resolution(VHR)imaging satellites,it is possible to measure the heights of forest stands or even individual trees more accurately.However,the accurate geometric processing of VHR images de...With the advent of very high-resolution(VHR)imaging satellites,it is possible to measure the heights of forest stands or even individual trees more accurately.However,the accurate geometric processing of VHR images depends on ground control points(GCPs).Collecting GCPs through fieldwork is time-consuming and labor-intensive,which presents great challenges for regional applications in remote or mountainous regions,particularly for international applications.This study proposes a promising approach that leverages GF-7 VHR stereoscopic images and Google Earth’s multi-temporal historical imagery to accurately extract forest heights without the need for fieldworks.Firstly,an algorithm is proposed to collect GCPs using Multi-temporal Averaging of historical imagery provided by Google Earth(GE),known as MAGE.Digital surface model(DSM)is then derived using GF-7 stereoscopic imagery and MAGE GCPs in Switzerland.Forest heights are finally extracted by subtracting ground surface elevations from GF-7 DSM.Results show that absolute coordinate errors of MAGE GCPs are less than 2.0 m.The root mean square error(RMSE)of forest heights extracted from GF-7 DSM,derived using the original geolocation model,is 12.3 m,and the determination coefficient(R^(2))of linear estimation model is 0.72.When the geolocation model is optimized using MAGE GCPs,the RMSE is reduced to 1.5 m and the R^(2)increases to 0.95.These results not only demonstrate the effectiveness of MAGE GCPs but,more importantly,also reveal the significance of precise geometric processing of VHR stereoscopic imagery in forest height estimations.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 30370815 and 30470332)
文摘To upscale the genetic parameters of CERES-Rice in regional applications, Jiangsu Province, the second largest rice producing province in China, was taken as an example. The province was divided into four rice regions with different rice variety types, and five to six sites in each region were selected. Then the eight genetic parameters of CERES-Rice, particularly the four parameters related to the yield, were modified and validated using the Trial and Error Method and the local statistical data of rice yield at a county level from 2001 to 2004, combined with the regional experiments of rice varieties in the province as well as the local meteorological and soil data （Method 1）. The simulated results of Method 1 were compared with those of other three traditional methods upscaling the genetic parameters, i.e., using one-site experimental data from a local representative rice variety （Method 2）, using local long-term rice yield data at a county level after deducting the trend yield due to progress of science and technology （Method 3）, and using rice yield data at a super scale, such as provincial, ecological zone, country or continent levels （Method 4）. The results showed that the best fitness was obtained by using the Method 1. The coefficients of correlation between the simulated yield and the statistical yield in the Method 1 were significant at 0.05 or 0.01 levels and the root mean squared error （RMSE） values were less than 9% for all the four rice regions. The method for upscaling the genetic parameters of CERES-Rice presented is not only valuable for the impact studies of climate change, but also favorable to provide a methodology for reference in crop model applications to the other regional studies.
基金This work is supported by the Universiti Kebangsaan Malaysia research grant GUP-2020-074.
文摘Broadband response metamaterial absorber(MMA)remains a challenge among researchers.A nanostructured new zero-indexed metamaterial(ZIM)absorber is presented in this study,constructed with a hexagonal shape resonator for optical region applications.The design consists of a resonator and dielectric layers made with tungsten and quartz(Fused).The proposed absorbent exhibits average absorption of more than 0.8972(89.72%)within the visible wavelength of 450–600 nm and nearly perfect absorption of 0.99(99%)at 461.61 nm.Based on computational analysis,the proposed absorber can be characterized as ZIM.The developments of ZIM absorbers have demonstrated plasmonic resonance characteristics and a perfect impedance match.The incidence obliquity in typically the range of 0◦–90◦both in TE and TM mode with maximum absorbance is more than 0.8972(∼89.72%),and up to 45◦angular stability is suitable for solar cell applications,like exploiting solar energy.The proposed structure prototype is designed and simulated by studying microwave technology numerical computer simulation(CST)tools.The finite integration technique(FIT)based simulator CST and finite element method(FEM)based simulator HFSS also helps validate the numerical data of the proposed ZIM absorber.The proposed MMA design is appropriate for substantial absorption,wide-angle stability,absolute invisible layers,magnetic resonance imaging(MRI),color images,and thermal imaging applications.
基金supported financially by the National Nature Science Foundation of China(No.41901129)the University Natural Sciences Research Project of Anhui Educational committee(2024AH050270)the support from the Joint China–Sweden Mobility Grant funded by NSFC and STINT(CH2019-8250)。
文摘Compared to lake area and water level,lake storage capacity more intuitively reflects regional climate changes.In this study,we first derived lakebed elevation profiles for individual ICESat-2 tracks based on the underwater stratification of laser photons,then integrating all valid elevation tracks within the water body to interpolate the bathymetry.On this basis,we calculated the capacity and its time series directly,with the aid of lake boundaries and water levels obtained from optical imagery and CryoSat-2 data.Next,we also applied an empirical formula to estimate the water volume changes of Bangdag Co by combining the area and water levels from 2010 to 2023.Finally,we compared the results of Bangdag Co's water volume changes obtained from the two different methods and conducted a detailed analysis of their performance and regional applicability.The bathymetric map of Bangdag Co reveals a distinct spatial pattern,with the northeastern part significantly deeper(with a maximum depth of 35.27 m)and the southwestern part shallower.The average depth of the lake is 13.99 m.We further estimated that the lake storage capacity in November 2023 was 2.95 km^(3).Water volume changes estimated using the empirical formula were highly consistent with those derived from the lake storage capacity time series(from 2010 to 2023,the lake storage capacity increased by 1.04 km^(3)).Our comparison revealed that the empirical formula method reflects only changes in water volume.In contrast,while our method can accurately estimate lake storage capacity,it is constrained to shallow,clear,and elongated east-west lakes(e.g.,Ayakkum Lake).In summary,the ICESat-2 laser altimetry data,which do not rely on measured water depths,offer an essential complement to underwater topography detection and provide a novel perspective on lake volume estimation research.
基金supported by the Youth Innovation Promotion Association of Chinese Academy of Sciences(No.Y201956)the Young Elite Scientists Sponsorship Program by China Association for Science and Technology(No.2023QNRC001)the National Key Research and Development Program of China(No.2017YFD200104).
文摘Soil mineralized nitrogen(N)is a vital component of soil N supply capacity and an important N source for rice growth.Unveiling N mineralization(Nm)process characteristics and developing a simple and effective approach to evaluate soil Nm are imperative to guide N fertilizer application and enhance its efficiency in various paddy soils with different physicochemical properties.Soil properties are important driving factors contributing to soil Nm differences and must be considered to achieve effective N management.Nevertheless,discrepancies in Nm capacity and other key influencing factors remain uncertain.To address this knowledge gap,this study collected 52 paddy soil samples from Taihu Lake Basin,China,which possess vastly different physicochemical properties.The samples were subjected to a 112-d submerged anaerobic incubation experiment at a constant temperature to obtain the soil Nm characteristics.Reaction kinetics models,including one-pool exponential model,two-pool exponential model,and effective cumulative temperature model,were employed to compare characteristic differences between Nm potential(Nmp)and short-term accumulated mineralized N(Amn)processes in relation to soil physicochemical properties.Based on these relationships,simplified Nmp prediction methods for paddy soils were established.The results revealed that the Nmp values were 145.18,88.64,and 21.03 mg kg-1 in paddy soils with pH<6.50,6.50≤pH≤7.50,and pH>7.50,respectively.Significantly,short-term Amn at day 14 showed a good correlation(P<0.01)with Nmp(R2=0.94),indicating that the prevailing short-term incubation experiment is an acceptable marker for Nmp.Moreover,Nmp correlated well with the ultraviolet absorbance value at 260 nm based on NaHCO3 extraction(Na260),further streamlining the Nmp estimation method.The incorporation of easily obtainable soil properties,including pH,total N(TN),and the ratio of total organic carbon to TN(C/N),alongside Na260 for Nmp evaluation allowed the multiple regression model,Nmp=58.62×TN-23.18×pH+13.08×C/N+86.96×Na260,to achieve a high prediction accuracy(R2=0.95).The reliability of this prediction was further validated with published data of paddy soils in the same region and other rice regions,demonstrating the regional applicability and prospects of this model.This study underscored the roles of soil properties in Nm characteristics and mechanisms and established a site-specific prediction model based on rapid extractions and edaphic properties of paddy soils,paving the way for developing rapid and precise Nm prediction models.
基金supported by the National Programme on Global Change and Air-Sea Interaction(Grant No.GASI-IPOVAI-01-06)the National Natural Science Foundation of China(Grant Nos. 41630967,41476018,U1406401 & 41421005)the CAS Strategic Priority Project(Grant No.XDA11020101)
文摘This study used a 1.5-layer reduced-gravity numerical model to investigate the nonlinear dynamics of Kuroshio intrusion into the Luzon Strait.The model results suggested that both basin-scale wind curl and lateral friction are the primary factors that control the transformation of the flow,although inertia also plays an important role.Using an idealized model,both the mechanism via which the flow pattern changes depending on the two primary factors and the occurrence of hysteresis were investigated.It was established that the transformation of the Kuroshio flow field between the four previously reported flow patterns(i.e.,leaping across,current looping,eddy shedding,and branch intruding) can be explained under a unified theoretical framework.A diagram is proposed to explain how the flow field transforms between the four patterns from a certain prior state when varying the values of the controlling factors.
基金sponsored by the National Natural Science Foundation of China(Grant Nos.42022009 and 42090013)the National Key Research and Development Program of China(2020YFE0200800).
文摘With the advent of very high-resolution(VHR)imaging satellites,it is possible to measure the heights of forest stands or even individual trees more accurately.However,the accurate geometric processing of VHR images depends on ground control points(GCPs).Collecting GCPs through fieldwork is time-consuming and labor-intensive,which presents great challenges for regional applications in remote or mountainous regions,particularly for international applications.This study proposes a promising approach that leverages GF-7 VHR stereoscopic images and Google Earth’s multi-temporal historical imagery to accurately extract forest heights without the need for fieldworks.Firstly,an algorithm is proposed to collect GCPs using Multi-temporal Averaging of historical imagery provided by Google Earth(GE),known as MAGE.Digital surface model(DSM)is then derived using GF-7 stereoscopic imagery and MAGE GCPs in Switzerland.Forest heights are finally extracted by subtracting ground surface elevations from GF-7 DSM.Results show that absolute coordinate errors of MAGE GCPs are less than 2.0 m.The root mean square error(RMSE)of forest heights extracted from GF-7 DSM,derived using the original geolocation model,is 12.3 m,and the determination coefficient(R^(2))of linear estimation model is 0.72.When the geolocation model is optimized using MAGE GCPs,the RMSE is reduced to 1.5 m and the R^(2)increases to 0.95.These results not only demonstrate the effectiveness of MAGE GCPs but,more importantly,also reveal the significance of precise geometric processing of VHR stereoscopic imagery in forest height estimations.
