Abstract:

LIDAR is a new technology for remote servey. Klette inversion algorithm is commontly used to solve LIDAR equation to determind the measurement parameters, such as backscattering efficient and extinction efficient. Because of the LIDAR equation has two aerosol unknown parameters, that is why the LIDAR ratio is needed. One can choose LIDAR ratio between from 20 - 90 sr. Therefore, it makes errors because of LIDAR ratio dependent on time and location. In the two stream methode two LIDAR instruments are integrated. Two instruments independendly measure with the same aerosol sample at the same time then giving two independend LIDAR equations. Assuming that laser is monochrome and complicated scattering is overlooked. Using the two stream methode to determind the efficient extinction and back scattering cofficient without any assuming or calibration. The efficient extinction and the backscattering dependend on the distance. The experiments calculating the dependence of the efficient extinction on the distance can conclude that there is an aerosol dame in distance from 0,3 km to 0,5 km. Caculating from experimental data get the backcattering efficient reduce in the distance from 0,3 km to 0.6 km. Therefore, the results of two efficient are well fit to each other. By the fomular, the LIDAR ratio is not constant. The LIDAR ratio dependends on the characteristics of the aerosol partical such as type, dimension and refractive index. These charateristics change by distance and the LIDAR ratio also depends on the distance. Experimental results showed that the LIDAR ratio depends on the distance and has maximum value 46 sr at 0.4 km and minimum value 17.5sr at 0.18 km so that it is fiting with theory of sea aerosol.