Looking for information about MOR mesurement

Hello everyone,
I am an newcomer here. Now I am interested in MOR(Meteorological Optical Range) measurement! Dose anyone have the same interest with me? Let's talk about it.
The main problem is that I can't find some useful materials about the method of the MOR measurement.

I want to apply the forward sattered method, but I don't konw the relation between the extinct coefficient and the power which the receiver gets. Some papers say that it's almost the linear relation, is it true? Is there any authoritative paper about the relation?

Let's talk about it!