Assessing the Uncertainty of Raman Lidar Independent Water Vapor Calibration Means for Long Term Water Vapor Trend Studies

The Network for the Detection of Atmospheric Composition Change (NDACC) and GCOS Reference Upper Air Network (GRUAN) both have lidar groups that desire to detect long term water vapor trends using Raman lidars. However, traditional calibration efforts make the lidar water vapor data dependent on water vapor measurements from other instruments. Also the traditional calibration efforts are known to be the largest source of systematic uncertainty to Raman Lidar water vapor data. Recently the lamp mapping technique (LMT) has been introduced as a source of independent calibration for Raman lidar water vapor data. However the systematic uncertainty from the LMT, as it applies to Raman Lidar water vapor data, needs to be investigated. Therefore the purpose of this research is to investigate the uncertainty and stability of the LMT as an independent calibration source and assess its capability to be used to support Raman Lidar long-term water vapor trend studies.