Lecture 7-01: Aerosol (Mie) lidar

Lecture 7-02: High-Spectral-Resolution Lidar (HSRL)

Standard backscatter lidar equation

20

( ) ( ) ( ) exp -2 ( ) ( )r

m p m pCP r r r r r drr

β β σ σ⎧ ⎫⎪ ⎪ʹ ʹ ʹ⎡ ⎤ ⎡ ⎤= + +⎨ ⎬⎣ ⎦ ⎣ ⎦⎪ ⎪⎩ ⎭∫

solving one equation with two unknowns - particulate backscatter and particulate extinction. The retrieval of both aerosol extinction and backscatter relies on an assumption of their ratio, 10 < Sa < 110

HSRL lidar equation

20

( )( ) exp -2 ( ) ( )MSMS

r

m m prCP r r r drr

β σ σ⎧ ⎫⎪ ⎪ʹ ʹ ʹ⎡ ⎤= +⎨ ⎬⎣ ⎦⎪ ⎪⎩ ⎭∫

20

( ) ( ) ( ) exp -2 ( ) ( )r

TSTS m p m p

CP r r r r r drr

β β σ σ⎧ ⎫⎪ ⎪ʹ ʹ ʹ⎡ ⎤ ⎡ ⎤= + +⎨ ⎬⎣ ⎦ ⎣ ⎦⎪ ⎪⎩ ⎭∫

Total scatter channel

“Molecular” channel

NASA/LaRC Airborn HSRL

System parameters for the airborne HSRL Transmitter

Repetition Rate 200 Hz 532 nm energy 4 mJ 1064 nm energy 1 mJ

Optical Receiver Telescope 0.4 m diameter 532 etalon FWHM 40 pm 1064 IF FWHM 1 nm

Detection Electronics 532 nm PMT, analog

detection 1064 nm APD with analog

detection

HSRL Deployed in NASA Langley King Air B200

The HSRL will provide vertically resolved measurements of the following extensive and intensive aerosol parameters: Extensive parameters - backscatter coefficient at 532 and 1064 nm; extinction coefficient 532 nm; optical depth at 532 nm (integrating the profile of extinction) Intensive parameters – S at 532 nm, depolarization at 532 nm and 1064 nm, and backscatter color ratio.

Example plots