Upgrades to Raman Lidar Backup Laser Improve Reliability

 
Published: 30 April 2004

The Raman Lidar is an active, ground-based laser remote sensing instrument that measures vertical profiles of water-vapor mixing ratio and several cloud- and aerosol-related quantities.

In March 2004, upgrades to a second (back-up) laser for the Raman Lidar at the ARM Climate Research Facility’s Southern Great Plains (SGP) locale were completed, concluding a complex effort that began more than a year ago. Upgrades included required modification to the optical layout of the lidar system, several changes to the laser head by the vendor (for compatibility with existing power supply equipment), the addition of a larger heat exchanger, and a second pump in the laser cooling system. This upgrade is expected to significantly improve the reliability of the Raman Lidar system. Now, if one laser fails, SGP personnel can bring the second laser on-line in a few minutes, rather than waiting days for the laser vendor to travel to the SGP and make repairs.

In preparation for the upgrade, an entirely new air handling system was installed in the SGP lidar shelter last summer. The new air handling equipment includes a much higher capacity air conditioner, new HEPA filtration, and an entirely new air distribution system to achieve more uniform distribution of the airflow in the shelter to avoid warm zones. Because of these improvements, the lidar will be able to operate satisfactorily during the hottest days of the Oklahoma summer, when ambient temperatures exceed 100 °F.