Question

2 1. Scattering cross-section of acrosol particles is 2.5E-12 m , absorption cross-section is 0.45E- .2 12 m Concentration of particles is N 2E7 1/m. Calculate the optical thickness and transmittance of atmosphere at this wavelength if sun zenith angle is 40 degrees and the thickness of aerosol layer is 2.5 km.

Answer 1

`T = 3.23 * 10^(-83)`

Step-by-step explanation:

thickness of aerosol layer is 2.5 km

zenith angle is 40 degree

we know that

`\tau = \epsilon_(ext) . h`

where

`\epsilon_(ext) = N.\sigma_(ext)`

`\epsilon_(ext)` is extinction coefficient

`\sigma_(ext)` extiction cross section

N = Concentration

`\sigma_(ext) = (2.5 + 0.45)* 10^(-12) m^2`

`= 2.95 * 10^(-12) m^2`

`\epsilon_(ext) = 2* 10^7 * 2.95 * 10^(-12) m^2 * m^(-3)`

`= 5.9 * 10^(-5) m^(1)`

`\tau = 5.9 * 10^(-5) m^(-1)  * 2.5* 10^3 m`

`= 14.75* 10^(-2)`

transimiitance
`T  = e^{(-\tau)/(\mu)}`

`T  = e^{(- 14.75 * 10^(-2))/(cos 40)}`

`T = 3.23 * 10^(-83)`