CO_215微米带大气透过率的计算

本文用直接积分的方法计算了CO_215微米带在水平大气路径和垂直大气路径上的透过率,并得出了一个能迅速和精确地计算CO_215微米带垂直路径大气透过率的模式的系数。     

CO2 15微米带大气透过率的计算

本文用直接积分的方法计算了CO_215微米带在水平大气路径和垂直大气路径上的透过率,并得出了一个能迅速和精确地计算CO_215微米带垂直路径大气透过率的模式的系数。     

CH4红外透过率的测定与计算

对ＣＨ４红外透过率的测定及计算作了介绍。测定是在实验室内进行的，主要设备是６０ＳＸＲＦＴＩＲ分光计及可变光程吸收池；计算用的是ＦＡＳＣＯＤＥ２程序。测定结果与计算结果作了比较。     

红外窗区大气透过率的测量

文章主要介绍了红外窗区太阳光谱测量的实验装置，观测方法和数据处理方法。处理了2390—3470 cm-1和750—1300 cm-1区域内的太阳光谱资料，得到了它们的大气透过率数据，并对处理结果进行了初步分析。我们认为这些大气透过率对气象卫星遥感仪器红外窗区通道选择和卫星气象资料反演等都是有用的。     

气体选择性吸收的透过度计算

当太阳短波和地气系统长波辐射在地气中传输时,在各种形式的衰减中,气体的选择性吸收很重要,它由吸收气体万分、吸收气体状态参数等决定,在反演大气温度和大气吸收成分含量以及计算地球大气的加热冷却等方面都有重要作用。本文的内容主要是气体选择性吸收透地率的各种计算方法。     

地球大气透过率及辐射率计算

文章介绍了一种比较简单实用的地球大气的光谱透过率和到达大气层顶的红外辐射率的计算模型,光谱波长从4 μm到∞ μm,吸收气体H2O、CO2、O3的吸收计算采用Elsasser带模式及其经验参数,H2O的连续吸收公式是美国LOWTRAN-6计算程序的水汽连续吸收经验公式。透过率的计算结果与LOWTRAN计算结果相一致。以这种透过率简化模型为基础,建立了辐射传递正演计算模型,开发了相应软件,并用于卫星遥感射出长波辐射的资料处理中,取得了良好结果。     

大气红外吸收带重迭及其处理方法对长波辐射计算的影响

本文详细地讨论了H_2O,CO_2,O_3,N_2O以及CH_4这五种大气主要红外活性气体的红外吸收带的重迭及其处理方法对长波冷却率及通量计算的影响.结果表明:气体吸收带的重迭对大气红外冷却率具有重要的作用;但在一定的误差范围内,不仅某些气体吸收带的重迭效应很小,可以忽略不计,而且某些重迭光谱区域对整个红外冷却率及通量的贡献亦可不予考虑.另外,本文还定性地讨论了处理重迭带的不同方法对红外辐射计算的影响.     

水汽红外冷却率的精确计算

本文用一种新的红外透过率模式计算了对流层和平流层水汽的长波(0—2380cm~(-1))冷却率分布.在计算中,我们精确处理了频率积分以及非均匀大气路径效应.结果表明:在近地面层,大气窗区(730—1200cm~(-1))(主要是水汽连续吸收)对总的冷却率贡献很大,在1公里处大约占72％;通常所用的处理非均匀大气路径及漫射辐射的CG近似和1.66漫射因子近似,基本上适用于水汽冷却率的计算.在整个对流层和平流层,它们所带来的最大误差不超过0.16K/日和0.19K/日.同时,我们还考查了水汽吸收系数的温度效应     

从红外太阳透过率反演大气可降水量的研究

从红外波段太阳透过率测量中可以反演大气可降水量#AW#a。我们在近、中红外波段选取了三对波长，用LOWTRAN 7辐射传输模式，主要研究了散射和气溶胶对这三对波长反演#AW#a算式的影响。结果表明，通常采用近红外波长对（即0.9422～0.862 μm）反演#AW#a并非最佳选择，因为其反演算式受到大气状态（混浊度）的很大影响；而在稍远段两对波长（1.47～1.55 μm和3.704～3.067 μm）对应的算式较为稳定。     

大气二氧化碳对CO2激光辐射各谱线的吸收

本文给出了大气二氧化碳对CO_2激光辐射各谱线吸收的计算公式,并利用标准大气资料计算了各谱线的吸收值。发现在P支谱线中,P(16)线吸收最大;在R支谱线中,R(16)线为最大。当转动量子数J大于或小于16时,吸收值随J值的增大或减小几乎成指数减小。为了验证计算公式的可靠性,在实验室中进行了模拟大气测量,其测量结果和理论计算结果具有较好的一致性。     

用选支CO激光研究NO,NO_2气体的吸收特性

本文利用国产XZJ—1型CO选支激光器测量了NO 5.2微米带和NO_2 6.2微米带49个激光频率处的吸收系数,对吸收变化特征进行了初步分析并且讨论了实验误差及实际大气监测中水汽干扰等问题.     

Parameterization of the Absorption of the H2O Continuum, CO2, O2, and Other Trace Gases in the Fu-Liou Solar Radiation Program

The absorption properties of the water vapor continuum and a number of weak bands for H2O, O2, CO2, CO, N2O, CH4, and O3 in the solar spectrum are incorporated into the Fu-Liou radiation parameterization program by using the correlated k-distribution method (CKD) for the sorting of absorption lines. The overlap absorption of the H2O lines and the H2O continuum (2500-14500 cm^-1) are treated by taking the two gases as a single-mixture gas in transmittance calculations. Furthermore, in order to optimize the computation efforts, CO2 and CH4 in the spectral region 2850-5250 cm^-1 are taken as a new singlemixture gas as well. For overlap involving other absorption lines in the Fu-Liou spectral bands, the authors adopt the multiplication rule for transmittance computations under which the absorption spectra for two gases are assumed to be uncorrelated. Compared to the line-by-line (LBL) computation, it is shown that the errors in fluxes introduced by these two approaches within the context of the CKD method are small and less than 0.48% for the H20 line and continuum in the 2500-14500 cm^-1 solar spectral region, -1% for H2O (line) H2O (continuum) CO2 CH4 in the spectral region 2850-5250 cm^-1, and -1.5% for H2O (line) H2O (continuum) O2 in the 7700-14500 cm^-1 spectral region. Analysis also demonstrates that the multiplication rule over a spectral interval as wide as 6800 cm^-1 can produce acceptable errors with a maximum percentage value of about 2% in reference to the LBL calculation. Addition of the preceding gases increases the absorption of solar radiation under all sky conditions. For clear sky, the increase in instantaneous solar absorption is about 9%-13% (-12 W m^-2) among which the H20 continuum produces the largest increase, while the contributions from O2 and CO2 rank second and third, respectively. In cloudy sky, the addition of absorption amounts to about 6-9 W m^-2. The new, improved program with the incorporation of the preceding gases produces a smaller solar absorption in clouds due to the reduced solar flux reaching the cloud top.     

A study on NO and NO2 absorption properties by using line-tunable CO laser

The absorption properties of NO in 5.2 μm band and NO2 in 6.2 μm band are measured for some definite wavelengths by using line-tunable CO laser and long-path absorption cell. The absorption coefficients for 49 CO laser wavelengths are given and variations of absorption withpartial and total pressures are analysed. Fur-thermore, the experimental errors and the interference of water vapour with the absorption at definite laser lines are also discussed.     

An open path,fast response infrared absorption gas analyzer for H2O and CO2

An open path infrared absorption based instrument for fast response measurements of H₂O and CO₂ fluctuations is described. This instrument performed reliably in several field experiments in both terrestrial and marine environments, on both fixed (tower) and mobile (boat, plane) flux platforms. Noise levels for H₂O and CO₂ concentrations were less than 10 mg/m³ and 300 g/m³, respectively for frequencies between 0.005 and 10 Hz. Drifts in instrument output, associated with changes in instrument temperature, are compensated for electronically.     

Siberian CO2 efflux in winter as a CO2 source and cause of seasonality in atmospheric CO2

Over three years, we found a consistent CO₂ efflux from forest tundra of the Russian North throughout the year, including a large (89 g C m^–2 yr^–1) efflux during winter. Our results provide one explanation for the observations that the highest atmospheric CO₂ concentration and greatest seasonal amplitude occur at high latitudes rather than over the mid-latitudes, where fossil fuel sources are large, and where high summer productivity offset by winter respiration should give large seasonal oscillations in atmospheric CO₂. Winter respiration probably contributed substantially to the boreal winter CO₂ efflux. Respiration is an exothermic process that produces enough heat to warm soils and promote further decomposition. We suggest that, as a result of this positive feedback, small changes in surface heat flux, associated with human activities in the North or with regional or global warming, could release large quantities of organic carbon that are presently stored in permafrost.     

Calculations of absorption,attenuation, and backscattering of hailstones and their possible applications

The absorption, attenuation, and backscattering of hailstones with various structures are investigated by the model calculations of four kinds of spherical hailstones: pure ice spheres, liquid water-coated ice spheres, spongy ice-coated ice spheres, and all spongy ice spheres. All the results for the wavelength 5.56 cm, including the radar reflectivity factor, absorption factor, and attenuation factor of hailstones with different size distributions are given and discussed in this paper. The possible applications of these character-istics in radar monitoring of hailstones are also discussed. It is shown that in certain conditions, a micro-wave radiometer simultaneously operating with a radar will be helpful to the identification of the hail-bearing area. Finally, the possible influence of hailfall area on the accuracy of the measurements of the rainfall distribution by using a radar-radiometer is simply discussed.     

Calculations of the temperature dependence of the NO2 photodissociation coefficient in the atmosphere

The photodissociation coefficient, J _NO2 of NO₂ in the atmosphere was calculated at 235 and 298 K using the measured temperature dependences of the absorption cross-sections and quantum yields. These calculations gave a ratio J _NO2(298 K)/J _NO2(235 K)=1.155±0.010 which is only weakly dependent on altitude, surface albedo and solar zenith angle.     

FY-2E云导风的算法改进及其在GRAPES中的同化应用研究

2014年国家卫星气象中心全面改进了风云二号卫星云导风产品算法,为评估算法改进后FY-2E云导风资料对我国GRAPES数值模式同化和预报的影响,根据国家卫星气象中心提供的2013年8月算法改进前后的FY-2E红外通道云导风资料,对比分析了两者的观测分布及偏差特征,并利用GRAPES全球模式进行了一个月的连续试验。结果表明,改进算法后的FY-2E红外通道云导风观测数量明显增加,观测误差在600~200 hPa有所减小,风的平均偏差在高层减少,更满足正态分布;连续试验结果表明北半球和东亚地区风场在300~150 hPa分析中改进显著,风的平均偏差和均方根误差明显减少;预报结果显示500 hPa高度场预报距平相关系数略提高,均方根误差略减小;说明改进算法后的FY-2E红外通道云导风对GRAPES数值模式同化和预报均有一定改善。