Calculation of Earth's atmospheric infrared radiation transmittance rate

1. Excel is used to calculate the atmospheric transmission rate of infrared radiation. The results are presented in the cell “N10” of the two worksheets. 

2. Cell “B7” in the worksheet 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 14.99% and 28.57% in N10, 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 coordinate; c. Calculate the corresponding wavelength at the step length of 0.1 (the result is displayed in column D); d. Find the 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 1.5 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.