Continuous lidar observations of aerosols and clouds in Tsukuba, Japan and Jakarta, Indonesia

To obtain a observational data set which can be used in the climate studies, the authors are conducting observations with ground based lidars. They started lidar observation with a scanning Mie scattering lidar at NIES in Tsukuba in 1979. They have developed the data analysis method which combines the lidar data and the simultaneous aureolemeter data, and obtained profiles of extinction coefficient of aerosols. This method, however, has a limitation, because it requires an assumption on spatial homogeniety of the optical property of aerosols. The observation, consequently, was limited on the clear days. To improve the frequency of the observation they developed a compact Mie scattering lidar which can be continuously operated. They also developed a high spectral resolution lidar (HSRL) for quantitative measurement of extinction and backscatter coefficients of aerosols and thin clouds. The authors also started observation with a similar Mie lidar in Jakarta in cooperation with Indonesian Institute of Science in 1997. The compact lidar at NIES is a simple vertically looking Mie scattering lidar. It employs a flashlamp pumped second harmonics Nd:YAG laser as a light source. The receiving telescope has a diameter of 35 cm. Photomultiplier tubes are used in the detection system, and the signals are recorded with analog-to-digital converters. Vertical profiles of scattering ratio are indicated for April 20, 1998. A Kosa event was observed on this day. The Mie lidar in Jakarta is a part of the lidar network system for measurement of air pollution in Jakarta.