Calculation of atmospheric infrared radiation transmittance rate

1. Excel is used to calculate the atmospheric transmission rate of infrared radiation. The worksheet “Earth” is the calculation of the transmission rate on the Earth and the worksheet “Hesperus” is the calculation of the transmission rate on Hesperus. Both of the results are presented in the cell “N19” of the two worksheets. The worksheet “Sheet 7” is the function diagram of the energy distribution and wavelengths of Hesperus. The worksheet “Wavelength Transmittance” is a reduction process of the transmission rates corresponding to the wavelengths with the step length of 0.1μm of the obtained image of “Radiation Transmitted by the Atmosphere”. 2. Cell “B7” in the worksheet “Earth” corresponds to the Earth’s surface temperature, the initial value of which is 288K. If the temperature is changed to 210K and 350K, that is, the value in B7 is changed to 210 and 350, the results would be 16.04% and 29.55% in N19, which is basically the same as the original 15-30%, indicating that the data is well restored according to the figures, and the calculation result of transmittance is correct. 3. There are three Plantwo of which are functions of corresponding wavelengths, and the relatick laws, onship between the two functions is a constant. Transmittance rate is a ratio, and both the numerator and denominator can present the constant outside the sum function for approximate division, so there is no difference between the results of choosing either of the two functions. 4. The restoring process of the figure of “Radiation Transmitted by the Atmosphere” is as follows: a. Grid the picture; b. Obtain the function of the number of grids corresponding to the horizontal coordinates: file:///C:\Users\ADMINI~1\AppData\Local\Temp\ksohtml12784\wps1.png, where n is the number of squares in the horizontal coordinates; c. Calculate the corresponding wavelength 10n/36.5-1 at the step length of 0.1 (the result is displayed in column D); d. Find the 1.3, 1.4, 1.5, 1.6 ......, 13.9, 14 μm in the wavelength, and check the corresponding number of horizontal coordinate squares n; e. Use the number of squares n in the “Total Absorption and Scattering” to find the corresponding atmospheric absorption rate r for that wavelength; f. Organize the data and list the 1.3 to 14 μm at the step length of 0.1 μm, and list the corresponding absorption rate r; g. Find the atmospheric transmission rate 1-r for wavelengths from 1.3 to 14 μm at the step length of 0.1 μm. Then the calculation would be easier. 5. Main radiation bands of CO2: 2.68-2.8 μm, 4.25-4.45 μm, 13-17 μm. Main radiation bands of H2O: 2.55-2.84 μm, 5.6-7.6 μm, 12-30 μm, all in the “Total Absorption and Scattering” atmospheric absorption range of infrared radiation. The calculation of transmission rate is not affected by the infrared radiation of CO2 and H2O. 6. According to the figure of “Radiation Transmitted by the Atmosphere”, the wavelength range of CO2 absorption of infrared radiation is limited. Although the atmospheric pressure of Hesperus is 96 atmospheres and the concentration of CO2 is 96.5%, CO2 has limited ability to absorb infrared radiation. The high temperatures on the surface of Venus cannot be explained only by the greenhouse effect. When calculating the atmospheric transmission rate of infrared radiation of Hesperus, the effect of carbon dioxide on the spectral absorption can be excluded by removing the 13-14 μm band from the calculation. 7. There is no independent H2CO3 in nature, which is the reason for the assumption that H2O collides with CO2 molecules without additional absorption of infrared radiation.

1. 本数据集采用Excel计算红外辐射的大气透射率。其中，工作表“Earth”用于计算地球表面的大气透射率，工作表“Hesperus”用于计算Hesperus（昏星，即金星）表面的大气透射率，二者的计算结果均存储于对应工作表的单元格N19中。工作表“Sheet 7”为Hesperus的能量分布与波长关系的函数示意图。工作表“Wavelength Transmittance”则用于对“Radiation Transmitted by the Atmosphere（大气透射辐射）”图像进行降维处理，提取步长为0.1μm的各波长对应的透射率数据。
2. 工作表“Earth”中的单元格B7对应地球表面温度，其初始值为288K。当将B7的数值修改为210K与350K时，单元格N19的计算结果分别为16.04%与29.55%，与初始范围15%~30%基本吻合，表明数据可通过图像良好还原，且透射率的计算结果准确无误。
3. 本数据集包含3个普朗克（Planck）函数，其中2个为对应波长的函数，二者的关系为常数。由于透射率为比值形式，分子与分母均可将求和函数外的常数提出以进行近似除法运算，因此选择二者中的任意一个函数，计算结果并无差异。
4. “大气透射辐射（Radiation Transmitted by the Atmosphere）”图像的还原流程如下：
a. 对图像进行网格化处理；
b. 获取与横坐标对应的方格数函数：file:///C:UsersADMINI~1AppDataLocalTempksohtml12784wps1.png，其中n为横坐标方向的方格总数；
c. 以步长0.1计算对应波长：$lambda = frac{10n}{36.5} - 1$（计算结果存储于D列）；
d. 提取波长范围为1.3μm、1.4μm、1.5μm……13.9μm、14μm的所有节点，并查询其对应的横坐标方格数n；
e. 通过“Total Absorption and Scattering（总吸收与散射）”中的方格数n，获取该波长对应的大气吸收率r；
f. 整理数据，以0.1μm为步长列出1.3μm至14μm的所有波长，并对应列出其吸收率r；
g. 对1.3μm至14μm、步长0.1μm的各波长，计算其大气透射率为$1-r$，以此简化计算流程。
5. 二氧化碳（CO₂）的主要辐射波段为：2.68~2.8μm、4.25~4.45μm、13~17μm；水（H₂O）的主要辐射波段为：2.55~2.84μm、5.6~7.6μm、12~30μm，所有波段均处于“总吸收与散射（Total Absorption and Scattering）”的红外辐射大气吸收范围内。透射率的计算不受CO₂与H₂O的红外辐射影响。
6. 根据“大气透射辐射”图像可知，CO₂对红外辐射的吸收波段范围有限。尽管Hesperus的大气压强为96标准大气压，CO₂浓度为96.5%，但其对红外辐射的吸收能力仍较为有限。金星表面的高温无法仅通过温室效应解释。在计算Hesperus的红外辐射大气透射率时，可通过移除13~14μm波段，排除CO₂对光谱吸收的影响。
7. 自然界中不存在独立的碳酸（H₂CO₃），这也是假设H₂O与CO₂分子碰撞时不会额外吸收红外辐射的依据。