Simultaneous two-wavelength lidar measurement of cloud and boundary layer aerosol extinction coefficients

• Main Authors: Vallar, Edgar A., Galvez, M. C. D.
• Format: text
• Published: Animo Repository 2001
• Subjects: Boundary layer (Meteorology); Optical radar in atmospheric chemistry; Wavelengths; Physics
• Online Access: https://animorepository.dlsu.edu.ph/faculty_research/2006
• Institution: De La Salle University

Simultaneous two wavelength LIDAR measurements of clouds and boundary layer aerosols were performed near Manila Bay, Philippines. The two-wavelength LIDAR system employs the simultaneous outputs at 1064-nm (420 mJ), and 532-nm (175 mJ) of a Q-Switched, 20-Hz Nd:YAG laser, and a 203.20-mm diameter Schmidt Cassegrain telescope set for 1-mrad field-of-view. The vertically-pointing, biaxial Mie LIDAR facility became operational early last year and is in the STRC building (14.339°N, 120.595°E) of De La Salle University (DLSU), Taft Avenue, Manila. LIDAR measurements were obtained in 1-minute intervals from 0812-0830 hours (local time) on December 20, 1999 and 0650-0930 hours (local time) on March 23, 2000. Extinction coefficients for these boundary layer aerosols and clouds were computed using Klett's modified inversion algorithm. The extinction coefficients for the clouds observed on December 20 were 20 - 100 km-1 (1064 nm) and 5 - 40 km-1 (532 nm). Boundary layer aerosols found on the same day had extinctions of 10 km-1 for both wavelengths and reached up to 300 m above the site. The March 23 data show mostly boundary, layer aerosols from 200 - 600 m above the LIDAR having extinction values of 6 - 8 km-1 for both wavelengths.