ueSTC 遥感地面数据采集与实验方法 1956 实验 实验三地物辐射参数采集实验 授课教师：周纪 办公室：创新中心B531 联系方式：jzhou233@uestc.edu.cn Incident Solar Radiation Reflected Atmosphere 口口 Gra Bare Soil Bullt-up Area
授课教师: 周 纪 办公室 : 创新中心B531 联系方式: jzhou233@uestc.edu.cn
1.辐射、热辐射与热红外遥感 热红外遥感应用非常广泛，如： 验方法》 灾害预警与监测（地震、林火、火山喷发等） 全球、区域气候变化（全球增温等 建筑能耗与人居环境评侍？城市热岛效应等) 环境监测（核电站废永监测等) 水文-生态过程（农田蒸散发、水资源管理等） 军事侦察
热红外遥感应用非常广泛，如： 灾害预警与监测（地震、林火、火山喷发等） 全球、区域气候变化（全球增温等） 建筑能耗与人居环境评估（城市热岛效应等） 环境监测（核电站废水监测等） 水文-生态过程（农田蒸散发、水资源管理等） 军事侦察
2.关键术语 2.1.1.9 Blackbody A blackbody is an ideal thermal emitter that transforms heat energy into radiant energy with maximum rate permitted by thermodynamic laws.Any real material at the same temperature cannot emit thermally at a rate exceeding that of a blackbody. Likewise,a blackbody must absorb and convert all incident radiant energy into heat energy regardless of the spectral band of the radiant energy (Colwell et al.1983). 9 2.1.1.14 Gray Body A gray body is a hypothetical source that would radiate as a blackbody but with an emissivity lower than unity and constant with wavelength.The gray body assumption is more useful as a first approximation to the actual emission of a real object or medium than is the ideal blackbody radiation.It is used in radiative transfer problem,for instance,in planetary atmospheres(Colwell et al.1983). 电寸
2.关键术语 2.1.1.10 Planck's Law Planck's law describes the spectral distribution of the radiation from a blackbody as (Planck 1914) B(T)= C (2.11) λ5[exp(号)-1] where Ba(T)is the spectral radiance [W m2 um sr]of a blackbody at temperature T [K]and wavelength A [um];Ci and C2 are the physical constants (C1=1.191×108Wum4sr-1m2,C2=1.439×104um.K). 2.1.1.11 Stefan-Boltzmann's Law Integrating the emitted radiance over the whole spectrum gives an expression for the total flux emitted by an isotropic blackbody of unit area.This is known as the Stefan-Boltzmann's law (Stefan 1879;Boltzmann 1884): M(T)=元。B(T)=aT4 (2.12) where M is the emitted radiant exitance,and o is the Stefan-Boltzmann constant (o=5.67×10-8Wm-2K-4)
2.关键术语 2.1.1.13 Spectral Emissivity (e) The land surface emissivity (s)is a measure of the ability of surface to emit thermal radiation.The spectral emissivity,s,is defined as the ratio of the spectral radiance,Ra(Is),emitted by a body at the temperature,I's,and the spectral radiance, Ba(Ts),emitted by a blackbody at the same temperature,Ts (Becker and Li 1995; Rees2001): Ra(Ts) (2.14) Bx(Ts) where Ba(Ts)is the Planck's law. 电子科技大
2.关键术语 2.1.1.18 Kirchhoff's Law In general,a medium that absorbs radiation may also emit radiation at the same wavelength.Kirchhoff's law states that the absorptivity of a body is equal to its emissivity at the same temperature (Kirchhoff 1860),namely, dk=8 (2.17) where ak is the absorptivity of a body.A body that is a good radiator (or emitter) is also a good absorber.Therefore,an ability to emit is oppositely related to its ability to reflect.Kirchhoff's law requires thermodynamic equilibrium,implying that the surface is isothermal and radiates to an isothermal background at the same temperature (Salisbury et al.1994).This relationship is often used to measure emissivity of materials by reflectance in laboratory. 电子科
2.关键术语 2.1.Thermodynamic or kinetic temperature A 'true'temperature would be measured with an accurate,infinitesimal in situ thermometer that makes good thermal contact with the object of interest.For our purposes,thermodynamic and kinetic temperatures are equal even though they are defined differently.Thermodynamic temperature is a macroscopic quantity that is constant throughout any group of subsystems that are in thermodynamic equilibrium (thermodynamic equilibrium means no heat transfer).The equilibrium condition for this group of subsystems can be derived by maximizing the total entropy with respect to the ， 电子科技大学周纪
2.关键术语 2.1.1.16 Radiometric Temperature or Skin Temperature (Tsr) Radiometric temperature(Tsr)is defined from the radiance,Ra,emitted by a surface (Norman and Becker 1995).If gx is the emissivity of this surface,the radiometric temperature is the temperature of a blackbody with radiance,Ra/sa,namely, R Tsr =B-1 (2.15) where B represents the inverse function of Planck's law.This radiometric temperature is also called skin temperature since it corresponds to the radiation emitted from a depth of the order of the penetration depth,namely,of the order of the wavelength.Radiometric and thermodynamic temperatures are equivalent to measure a surface temperature that can be used in the heat flux equation with appropriate resistance.However,for heterogeneous and nonisothermal surfaces, those temperatures are different,and the skin temperature measured by a radiometer is no longer equal to the bulk temperature measured by a thermometer.This leads to great difficulties in relating large-scale radiometric temperature to thermometric measurement and therefore to the heat fluxes
2.关键术语 2.1.1.17 Brightness Temperature (Tp) Brightness temperature(Tp)is a directional temperature obtained by equating the measured radiance with the integral over wavelength of the Planck's law times the sensor response.It is the temperature of a blackbody that would have the same radiance as the radiance actually observed with the sensor (Norman and Becker 1995),namely, [ 人2 To=B-I (2.16) where B represents the inverse function of Planck's law,A is the wavelength,A and A2 are the lower and upper wavelengths of sensitivity of the sensor in channel i,and Ra is the measured radiance at wavelength A,fi()is the spectral response function of the sensor in channel i
3.常用的热辐射测量仪器 (1)手持式红外辐射计 产品技术指标 红外测温范围 566:-40C至650C(-40℉至1202℉) 568:-40C至800℃(-40℉至1472℉) 红外测温淮确度 0C(32F:±1%或±1.0℃（±2.0℉），以较大值为难 显示分滑率 0.1C/0.1℉ 红外光谱响应 8um至14um 红外响应时间 <500m5ec K型热电偶输入温度范用 -270℃至1372℃(-454℉至2501℉) K型热电偶输入准确度 -270C至 =(1℃+0.2/1C)(-454℉至-40F:±(2F+0.2 -40°C: e/1F)) -40°℃至 1%或1℃(-40F至2501F:±1%或2F),以较大值 1372C: 为 D:5(距离与测里光点直径的 566:30:1 比率) 568:50:1 激光瞄准 单点激光<1mw输出，2类（仙操作，630nm至670nm 最小光点直径 19毫米(0.75英寸) 发射车调节 通过内置普通材料表或数字调节，范围为0.10至1.00，调幅0.01 带日期/时间标记的数据存储 566:20点 568:99点
(1)手持式红外辐射计