The Microwave Land Surface Emissivity(MLSE)atlas and instantaneous simulation of all-sky/all-surface MLSE are important prerequisites for satellite data assimilation.A ten-day/month synthesized FengYun-3D MLSE atlas(N...The Microwave Land Surface Emissivity(MLSE)atlas and instantaneous simulation of all-sky/all-surface MLSE are important prerequisites for satellite data assimilation.A ten-day/month synthesized FengYun-3D MLSE atlas(New_FY3D)was constructed by the two global MLSE daily product datasets,clear-sky(FY-3D1)and clear/cloudy(FY-3D2),which were retrieved from the same FY-3D MicroWave Radiation Imager(MWRI)Level-1 brightness temperature(BT)data from 2021 to 2022,respectively.Then,a set of global MLSE label samples based on the New_FY3D,including 14 surface geophysical parameters,was obtained for an instantaneous global MLSE simulation at a 0.10°spatial resolution by adopting the extreme gradient boosting(XGBoost)machine learning method.Finally,the FengYun-3F(FY-3F)MWRI-II BT simulations using the Advanced Radiative Transfer Modeling System(ARMS)based on the above different MLSE products were evaluated.The results show that the New_FY3D atlas performs well,and the BT simulation at the top of atmosphere is better than that of FY-3D1,FY-3D2,and the international mainstream TELSEM2(Version 2.0 for a Tool to Estimate Land Surface Emissivities in the Microwaves)atlas.Surface roughness,vegetation coverage,land cover type,and snow cover are vital parameters for MLSE simulation.The XGBoost model can accurately simulate all-sky/all-surface MLSE instantaneously over the frequency range 10.65–89.0 GHz.The average simulation determination coefficients(R^(2))under clear-sky and cloud-sky conditions are 0.925 and 0.901,respectively,and the average root-mean-square errors(RMSEs)are 0.018 and 0.021,respectively.Large simulation errors occur in permanent wetland,ice and snow,and urban and built-up areas.With a standard deviation of 6.6 K,the BT simulation based on an XGBoost simulated MLSE is better than those based on New_FY3D and TELSEM2.展开更多
The concept of emissivity has been with the scientific and engineering world since Planck formulated his blackbody radiation law more than a century ago.Nevertheless,emissivity is an elusive concept even for ex⁃perts....The concept of emissivity has been with the scientific and engineering world since Planck formulated his blackbody radiation law more than a century ago.Nevertheless,emissivity is an elusive concept even for ex⁃perts.It is a vague and fuzzy concept for the wider community of engineers.The importance of remote sensing of temperature by measuring IR radiation has been recognized in a wide range of industrial,medical,and environ⁃mental uses.One of the major sources of errors in IR radiometry is the emissivity of the surface being measured.In real experiments,emissivity may be influenced by many factors:surface texture,spectral properties,oxida⁃tion,and aging of surfaces.While commercial blackbodies are prevalent,the much-needed grey bodies with a known emissivity,are unavailable.This study describes how to achieve a calibrated and stable emissivity with a blackbody,a perforated screen,and a reliable and linear novel IR thermal sensor,18 dubbed TMOS.The Digital TMOS is now a low-cost commercial product,it requires low power,and it has a small form factor.The method⁃ology is based on two-color measurements,with two different optical filters,with selected wavelengths conform⁃ing to the grey body definition of the use case under study.With a photochemically etched perforated screen,the effective emissivity of the screen is simply the hole density area of the surface area that emits according to the blackbody temperature radiation.The concept is illustrated with ray tracing simulations,which demonstrate the approach.Measured results are reported.展开更多
Infrared radiation(IR)ceramics have been recognized as energy-saving materials for high-temperature industry due to excellent IR performance.However,for conventional IR ceramics,low emissivity in partial band and emis...Infrared radiation(IR)ceramics have been recognized as energy-saving materials for high-temperature industry due to excellent IR performance.However,for conventional IR ceramics,low emissivity in partial band and emissivity degradation during high-temperature service restricted the practical application.Herein,we integrated broad-band high emissivity and slow degradation rate in novel high-entropy perovskite ceramics:La(Al_(0.2)Co_(0.2)Fe_(0.2)Ni_(0.2)Cr_(0.2))O_(3−δ)(HE-1) and La(Al_(0.2)Co_(0.2)Fe_(0.2)Ni_(0.2)Mn_(0.2))O_(3−δ)(HE-2).Specifically,the high-energy ceramic HE-1&HE-2 displayed high emissivity of 0.94/0.90 and 0.90/0.95 in the broad-band of near/mid-infrared(0.76–14µm).This excellent IR performance can be attributed to impurity energy level absorption,free carrier absorption,and lattice vibration absorption.During high-temperature service,these high-entropy ceramics have much slower emissivity degradation rate than conventional IR ceramic,because of hysteresis diffusion effect.Additionally,energy-saving ratios of 17.70%and 10.77%were realized by heating water with porous burner containing HE-1 and HE-2 coating respectively,due to enhanced heat radiation in systems.Thus,these high-entropy IR ceramics have significant application potential for long-term energy-saving in high-temperature industry.展开更多
The rapid evolution of hypersonic vehicle technologies necessitates robust thermal protection systems capable of withstanding extreme oxidative ablation.This study introduces a novel gradient-architected ZrB_(2)-MoSi_...The rapid evolution of hypersonic vehicle technologies necessitates robust thermal protection systems capable of withstanding extreme oxidative ablation.This study introduces a novel gradient-architected ZrB_(2)-MoSi_(2)-SiC dense layer embedded within a lightweight three-dimensional(3D)needled carbon fiber composite.Utilizing the volatility of ethanol and polycarbosilane,the ceramic slurry is selectively infused into targeted regions of the fibrous structure,optimizing the ZrB_(2)to MoSi_(2)ratio to enhance performance.The resulting dense layer exhibits exceptional emissivity,surpassing 0.90 in the 1-3μm range and exceeding 0.87 in the 2-14μm range.Moreover,it demonstrates remarkable oxidative ablation resistance.Specifically,at an optimized ZrB_(2)to MoSi_(2)ratio of 6:4,the dense layer achieves a minimal linear ablation rate of 0.015μm·s^(-1) under a 1.5 MW·m^(-2)oxyacetylene flame for 1000 s.Even after exposure to oxyacetylene ablation at surface temperatures of approximately 1750℃for 1000 s,the dense layer retains its structural integrity,highlighting its enduring oxidation resistance.The incorporation of MoSi_(2)not only enhances emissivity but also fortifies the ZrO_(2)and SiO_(2)oxide layers,crucial for environments with elevated oxygen levels,thereby mitigating the active oxidation of SiC.This combination of high emissivity and long-term oxidation resistance at ultra-high temperatures positions the ZrB_(2)-MoSi_(2)-SiC dense layer as an exceptionally promising candidate for advanced thermal protection in hypersonic vehicles.展开更多
池塘养殖是我国主要的养殖模式,也是潜在的温室气体排放源。为探究典型草鱼养殖池塘二氧化碳(CO2)、甲烷(CH4)、氧化亚氮(N2O)通量特征及其驱动因素,以1龄(GC1)、2龄(GC2)和3龄(GC3)草鱼养殖池塘为对象,采用静态箱-气相色谱法原位监测...池塘养殖是我国主要的养殖模式,也是潜在的温室气体排放源。为探究典型草鱼养殖池塘二氧化碳(CO2)、甲烷(CH4)、氧化亚氮(N2O)通量特征及其驱动因素,以1龄(GC1)、2龄(GC2)和3龄(GC3)草鱼养殖池塘为对象,采用静态箱-气相色谱法原位监测气体通量,分析其排放强度及与环境因子的关系。结果显示,温室气体通量依次为GC3>GC2>GC1,GC3的CO2、CH4和N2O平均通量分别为42.30、13.31 mg/(m2·h)和567.25μg/(m2·h),所有池塘均为CH4的排放源。冗余分析表明,GC1气体通量主要受NO3-N和底泥温度影响,GC2以水温为主导,GC3则受底泥温度和溶解氧控制。直接排放系数分析显示,GC3池塘CO2、CH4和N2O排放系数分别为132.98、41.91和1.77 g/kg,均显著高于GC1和GC2(P<0.05)。单位面积增温潜势表现为GC3 (53.48 t CO2-eq/hm2)>GC2(31.84 t CO2-eq/hm2)>GC1 (6.54 t CO2-eq/hm2),差异显著(P<0.05)。单位产量温室气体排放强度在GC1、GC2和GC3中分别为0.26、1.05和1.95 t CO2-eq/t,差异显著(P<0.05)。养殖规格显著影响草鱼池塘温室气体排放强度,高温与大规格养殖加剧碳排放,建议通过调控养殖结构与环境因子,推动渔业碳中和。展开更多
基金supported by the National Natural Science Foundation of China(Grant No.U2242211)the Hunan Provincial Natural Science Foundation Major Project(Grant No.2021JC0009).
文摘The Microwave Land Surface Emissivity(MLSE)atlas and instantaneous simulation of all-sky/all-surface MLSE are important prerequisites for satellite data assimilation.A ten-day/month synthesized FengYun-3D MLSE atlas(New_FY3D)was constructed by the two global MLSE daily product datasets,clear-sky(FY-3D1)and clear/cloudy(FY-3D2),which were retrieved from the same FY-3D MicroWave Radiation Imager(MWRI)Level-1 brightness temperature(BT)data from 2021 to 2022,respectively.Then,a set of global MLSE label samples based on the New_FY3D,including 14 surface geophysical parameters,was obtained for an instantaneous global MLSE simulation at a 0.10°spatial resolution by adopting the extreme gradient boosting(XGBoost)machine learning method.Finally,the FengYun-3F(FY-3F)MWRI-II BT simulations using the Advanced Radiative Transfer Modeling System(ARMS)based on the above different MLSE products were evaluated.The results show that the New_FY3D atlas performs well,and the BT simulation at the top of atmosphere is better than that of FY-3D1,FY-3D2,and the international mainstream TELSEM2(Version 2.0 for a Tool to Estimate Land Surface Emissivities in the Microwaves)atlas.Surface roughness,vegetation coverage,land cover type,and snow cover are vital parameters for MLSE simulation.The XGBoost model can accurately simulate all-sky/all-surface MLSE instantaneously over the frequency range 10.65–89.0 GHz.The average simulation determination coefficients(R^(2))under clear-sky and cloud-sky conditions are 0.925 and 0.901,respectively,and the average root-mean-square errors(RMSEs)are 0.018 and 0.021,respectively.Large simulation errors occur in permanent wetland,ice and snow,and urban and built-up areas.With a standard deviation of 6.6 K,the BT simulation based on an XGBoost simulated MLSE is better than those based on New_FY3D and TELSEM2.
文摘The concept of emissivity has been with the scientific and engineering world since Planck formulated his blackbody radiation law more than a century ago.Nevertheless,emissivity is an elusive concept even for ex⁃perts.It is a vague and fuzzy concept for the wider community of engineers.The importance of remote sensing of temperature by measuring IR radiation has been recognized in a wide range of industrial,medical,and environ⁃mental uses.One of the major sources of errors in IR radiometry is the emissivity of the surface being measured.In real experiments,emissivity may be influenced by many factors:surface texture,spectral properties,oxida⁃tion,and aging of surfaces.While commercial blackbodies are prevalent,the much-needed grey bodies with a known emissivity,are unavailable.This study describes how to achieve a calibrated and stable emissivity with a blackbody,a perforated screen,and a reliable and linear novel IR thermal sensor,18 dubbed TMOS.The Digital TMOS is now a low-cost commercial product,it requires low power,and it has a small form factor.The method⁃ology is based on two-color measurements,with two different optical filters,with selected wavelengths conform⁃ing to the grey body definition of the use case under study.With a photochemically etched perforated screen,the effective emissivity of the screen is simply the hole density area of the surface area that emits according to the blackbody temperature radiation.The concept is illustrated with ray tracing simulations,which demonstrate the approach.Measured results are reported.
基金financially supported by the National Natural Science Foundation of China(Nos.52372029,U22A20127,52304356,and 92263205)the Key R&D Plan Project in Hubei Province(No.2023BCB100).
文摘Infrared radiation(IR)ceramics have been recognized as energy-saving materials for high-temperature industry due to excellent IR performance.However,for conventional IR ceramics,low emissivity in partial band and emissivity degradation during high-temperature service restricted the practical application.Herein,we integrated broad-band high emissivity and slow degradation rate in novel high-entropy perovskite ceramics:La(Al_(0.2)Co_(0.2)Fe_(0.2)Ni_(0.2)Cr_(0.2))O_(3−δ)(HE-1) and La(Al_(0.2)Co_(0.2)Fe_(0.2)Ni_(0.2)Mn_(0.2))O_(3−δ)(HE-2).Specifically,the high-energy ceramic HE-1&HE-2 displayed high emissivity of 0.94/0.90 and 0.90/0.95 in the broad-band of near/mid-infrared(0.76–14µm).This excellent IR performance can be attributed to impurity energy level absorption,free carrier absorption,and lattice vibration absorption.During high-temperature service,these high-entropy ceramics have much slower emissivity degradation rate than conventional IR ceramic,because of hysteresis diffusion effect.Additionally,energy-saving ratios of 17.70%and 10.77%were realized by heating water with porous burner containing HE-1 and HE-2 coating respectively,due to enhanced heat radiation in systems.Thus,these high-entropy IR ceramics have significant application potential for long-term energy-saving in high-temperature industry.
基金supported by the National Natural Science Foundation of China(Nos.52272060,51902067,51872066 and 52172041)the Key Program of National Natural Science Foundation of China(No.52032003)+5 种基金the Young Elite Scientists Sponsorship Program by CAST(No.2020QNRC001)China Postdoctoral Science Foundation(Nos.2019M651282 and 2022T150157)Heilongjiang Provincial Postdoctoral Science Foundation(Nos.LBH-Z19022 and LBH-TZ2207)Heilongjiang Touyan Innovation Team Program,Shanghai Aerospace Science and Technology Innovation Fund(No.SAST2019-012)the Fundamental Research Funds for the Central Universities(No.FRFCU5710051022)the Science Foundation of National Key Laboratory of Science and Technology on Advanced Composites in Special Environments(No.JCKYS2022603C011).
文摘The rapid evolution of hypersonic vehicle technologies necessitates robust thermal protection systems capable of withstanding extreme oxidative ablation.This study introduces a novel gradient-architected ZrB_(2)-MoSi_(2)-SiC dense layer embedded within a lightweight three-dimensional(3D)needled carbon fiber composite.Utilizing the volatility of ethanol and polycarbosilane,the ceramic slurry is selectively infused into targeted regions of the fibrous structure,optimizing the ZrB_(2)to MoSi_(2)ratio to enhance performance.The resulting dense layer exhibits exceptional emissivity,surpassing 0.90 in the 1-3μm range and exceeding 0.87 in the 2-14μm range.Moreover,it demonstrates remarkable oxidative ablation resistance.Specifically,at an optimized ZrB_(2)to MoSi_(2)ratio of 6:4,the dense layer achieves a minimal linear ablation rate of 0.015μm·s^(-1) under a 1.5 MW·m^(-2)oxyacetylene flame for 1000 s.Even after exposure to oxyacetylene ablation at surface temperatures of approximately 1750℃for 1000 s,the dense layer retains its structural integrity,highlighting its enduring oxidation resistance.The incorporation of MoSi_(2)not only enhances emissivity but also fortifies the ZrO_(2)and SiO_(2)oxide layers,crucial for environments with elevated oxygen levels,thereby mitigating the active oxidation of SiC.This combination of high emissivity and long-term oxidation resistance at ultra-high temperatures positions the ZrB_(2)-MoSi_(2)-SiC dense layer as an exceptionally promising candidate for advanced thermal protection in hypersonic vehicles.
文摘池塘养殖是我国主要的养殖模式,也是潜在的温室气体排放源。为探究典型草鱼养殖池塘二氧化碳(CO2)、甲烷(CH4)、氧化亚氮(N2O)通量特征及其驱动因素,以1龄(GC1)、2龄(GC2)和3龄(GC3)草鱼养殖池塘为对象,采用静态箱-气相色谱法原位监测气体通量,分析其排放强度及与环境因子的关系。结果显示,温室气体通量依次为GC3>GC2>GC1,GC3的CO2、CH4和N2O平均通量分别为42.30、13.31 mg/(m2·h)和567.25μg/(m2·h),所有池塘均为CH4的排放源。冗余分析表明,GC1气体通量主要受NO3-N和底泥温度影响,GC2以水温为主导,GC3则受底泥温度和溶解氧控制。直接排放系数分析显示,GC3池塘CO2、CH4和N2O排放系数分别为132.98、41.91和1.77 g/kg,均显著高于GC1和GC2(P<0.05)。单位面积增温潜势表现为GC3 (53.48 t CO2-eq/hm2)>GC2(31.84 t CO2-eq/hm2)>GC1 (6.54 t CO2-eq/hm2),差异显著(P<0.05)。单位产量温室气体排放强度在GC1、GC2和GC3中分别为0.26、1.05和1.95 t CO2-eq/t,差异显著(P<0.05)。养殖规格显著影响草鱼池塘温室气体排放强度,高温与大规格养殖加剧碳排放,建议通过调控养殖结构与环境因子,推动渔业碳中和。
