Optimization of the lidar optical design for measurement of the aerosol extinction vertical profile

Alessia Sannino,Antonella Boselli,Gaetano Sasso,Nicola Spinelli,Xuan Wang,L Valore,F Guarino,R Colalillo

doi:10.1051/epjconf/201919702006

Abstract

A lidar for aerosol monitoring with conventional optical design can provide good quality signals from several hundred meters up to tens of kilometres above the ground, but the aerosol load is mainly contained (up to 80%) in the planetary boundary layer that can have a height of only hundreds of meters above the ground level. Therefore, the measurement of the complete aerosol extinction profile is generally a very difficult challenge. In this paper, we proposed an optical design of lidar systems able of producing signals starting from a few tens of meters above the ground. The overlap profiles obtained from an optimized lidar was compared with ray tracing simulations and further conventional lidar apparatuses.

Highlights

The most performing lidars have an overlap function (OF) which becomes equal to 1 only at a height higher than 800m, rejecting, in ground-based lidar systems, the information from the atmospheric part with the highest density of aerosols and aerosol processes
The uncertainty introduced by the correction of the OF, if possible, prevents the inversion of the data lidar for the purpose of obtaining the optical parameters and the microphysical characteristics of the aerosols at low altitude. [2,3,4] In this paper a new optical design of lidar systems has been considered by using ray tracing simulations to determine the overlap function profiles
We choose a monostatic configuration of the system using a secondary mirror with reduced dimension and a larger telescope FOV allowing the laser beam to lap over the mirror shadow at lower altitude

Summary

Introduction

The most performing lidars have an OF which becomes equal to 1 (full overlap) only at a height higher than 800m, rejecting, in ground-based lidar systems, the information from the atmospheric part with the highest density of aerosols and aerosol processes. [2,3,4] In this paper a new optical design of lidar systems has been considered by using ray tracing simulations to determine the overlap function profiles.

Results

Conclusion