The Australian Antarctic Lidar Facility

Abstract

A high spectral resolution lidar, under development by the Australian Antarctic Division and the University of Adelaide, is described. This instrument will be stationed at Davis, Antarctica (68.6° S, 78.0° E) from early 1996 for the long-term measurement of atmospheric parameters as a function of altitude from the lower stratosphere to the mesopause. The siting of the lidar will allow for data comparison with existing optical, radar, and balloon-borne atmospheric studies. Research utilizing the multi-instrument database will be aimed at assessing climatic variability and coupling processes throughout the atmosphere. The lidar transmitter consists of a commercial injection-seeded pulsed Nd:YAG laser coupled to a altazimuth mounted Cassegrain telescope with a 1 meter diameter primary mirror. The laser emits at a wavelength of 532 nm with an average power of 30 W. The telescope also serves as the collecting optics for the receiving system. The lidar is switched between transmit and receive modes by a high speed rotating shutter system. The detection system consists of a dual scanning Fabry Perot spectrometer (FPS) followed by a cooled photomultiplier operated in `photon counting' mode. The received signal is integrated as a function of equivalent range over a bandpass that may be either fixed or scanned in the wavelength domain. Performance simulations for the fixed bandpass operating mode are discussed. These indicate that useful measurements of density and inferred temperature should be achievable for the mesopause region, particularly at night and during twilight. In addition, detection of clouds in the mesosphere during the day appears feasible.