First Data from Darwin Raman Lidar

Published: 28 December 2010

Since 1996, the ARM Southern Great Plains site has maintained one of the few operational Raman lidars in the world, providing one of the most requested ARM data sets from the site. Now, with the installation of a new Raman lidar, the ARM Tropical Western Pacific site has joined that exclusive group.

Some of the first data gathered from the Raman lidar operating at Darwin show water vapor and cloud structure on December 6, 2010. Click the data plot to view the full-size image.
“First light” data were gathered on December 6, 2010 by the Darwin Raman lidar and were processed at very high temporal and spatial resolution to provide a detailed view of the water vapor mixing ratio above the site. The Darwin Raman lidar is the first operational Raman lidar in the tropics and and the only active remote sensing instrument capable of providing simultaneous measurements of water vapor, clouds, and aerosols at the Darwin site. It provides a useful complement to data collected by the other instruments at the site.

The water vapor Raman lidar provides profiles of water vapor mixing ratio at high vertical and temporal resolution, up to 7.5 meters vertical and 10 seconds temporal.
Raman lidars (light detection and ranging) use pulses of laser radiation to probe the atmosphere. A telescope collects the backscattered radiation that returns, and the optics inside the laboratory shelter measure the backscatter at different wavelengths to derive time- and altitude-resolved profiles of atmospheric water vapor, aerosols, clouds, and temperature.

The Darwin Raman lidar is very similar to the SGP system and was constructed and tested at Sandia National Laboratories. It was shipped to Darwin in October.