Affordable lidar for atmospheric aerosol and cloud studies

摘要

The Vaisala ceilometer LD-40 "Tropopauser" is a compact eye-safe lidar measuring continuously under all possible climatic conditions and scanning the atmosphere up to a height of 13000 m. It uses laser diodes with 855 nm wavelength that are pulsed at an average frequency of 4000 Hz. The distance of the system's range bins is 7.5 m. Its main purpose is reporting cloud base heights and vertical visibility for aviation safety purposes. This paper focuses on the additional parameters this affordable lidar is able to report due to its advanced technical properties. These parameters include kind of precipitation detected, presence and distance of cirrus, extinction coefficients within clouds, vertical profiles of planetary boundary layer backscatter power, and a comparison of cloud coverage detected by a ceilometer with values obtained with a total cloud coverage scanner. Comparison instruments include regular radiosonde soundings performed at the Meteorological Observatory Lindenberg of the German Weather Service.