7. Conclusion

This article presented the direct lidar operation to obtain the useful optical signal. The principles, instrumentation and spectroscopies involved in lidar measurements were described, with a presentation of the concepts and equations used in the article [E 4 311] to describe the various lidar methods depending on the light-matter interaction processes involved: elastic or Raman scattering, differential absorption, Doppler effect. Numerical applications show the respective roles of instrumental and atmospheric quantities in the link budget and signal-to-noise ratio. The article