Hi Reham,
It is my understanding that you want to convert the units used for the extinction coefficient in the STK system tool kit. To use the Beer-Lambert law in the Systems Tool Kit (STK) for modelling laser propagation through a medium like a cloud, you need to convert the attenuation value from dB/km to m⁻¹.
You can convert the attenuation by changing it into a linear scale in terms of power loss per kilometre by performing 
. For 1.2 db/km, the linear loss becomes 
which is approximately equal to 1.318. Now since the linear loss is in km⁻¹, we convert it to meter inverse by dividing by 1000. Therefore, the extinction coefficient becomes 0.001318 m⁻¹.
. For 1.2 db/km, the linear loss becomes which is approximately equal to 1.318. Now since the linear loss is in km⁻¹, we convert it to meter inverse by dividing by 1000. Therefore, the extinction coefficient becomes 0.001318 m⁻¹. You can then enter the calculated extinction coefficient into the extinction parameters and specify the layer top based on the data and assumptions for your scenario. You can then run a simulation to verify that the attenuation effects are accurately modelled. By following the above steps, you can effectively model the attenuation effects of a cloud layer in STK using the Beer-Lambert law with the extinction coefficient derived from your specified attenuation values.
Hope this helps!
