Raman Lidar Measurements during the International H2O Project. Part II: Case Studies

Abstract

The NASA GSFC Scanning Raman Lidar (SRL) participated in the International H2O Project (IHOP) that occurred in May and June 2002 in the midwestern part of the United States. The SRL system configuration and methods of data analysis were described in Part I of this paper. In this second part, comparisons of SRL water vapor measurements and those of Lidar Atmospheric Sensing Experiment (LASE) airborne water vapor lidar and chilled-mirror radiosonde are performed. Two case studies are then presented: one for daytime and one for nighttime. The daytime case study is of a convectively driven boundary layer event and is used to characterize the daytime SRL water vapor random error characteristics. The nighttime case study is of a thunderstorm-generated cirrus cloud case that is studied in its meteorological context. Upper-tropospheric humidification due to precipitation from the cirrus cloud is quantified as is the cirrus cloud optical depth, extinction-to-backscatter ratio, ice water content, cirrus particle size, and both particle and volume depolarization ratios. A stability and back-trajectory analysis is performed to study the origin of wave activity in one of the cloud layers. These unprecedented cirrus cloud measurements are being used in a cirrus cloud modeling study

The water vapour intercomparison effort in the framework of the Convective and Orographically‐induced Precipitation Study: airborne‐to‐ground‐based and airborne‐to‐airborne lidar systems

“…The present work aims at providing error estimates for the water vapour profiles measured by different water vapour lidars based on an intensive intercomparison effort. Comparisons between airborne DIAL and ground-based Raman lidars have already been reported in the literature (Whiteman et al, 2006;Behrendt et al, 2007a,b). The papers by Behrendt et alreport on the largest intercomparison effort between water vapour lidar systems performed so far, which was conducted in the frame of the IHOP 2002 project (Weckwerth et al, 2004).…”

Can Water Vapour Raman Lidar Resolve Profiles of Turbulent Variables in the Convective Boundary Layer?

“…In a Raman lidar it can be assumed that the noise is Poisson distributed, which can be propagated using an end-to-end model into an error of mixing ratio (e.g., Eq. 6 in Whiteman et al 2006). Noise profiles can also be determined without application of end-to-end models.…”

“…Raman lidar systems also have the capability of measuring water vapour mixing ratio at high temporal and spatial resolutions (e.g., Turner and Goldsmith 1999;Whiteman et al 2006;Ferrare et al 2006). However, the following question arises: is the accuracy and resolution of state-of-the-art water vapour Raman lidar systems sufficient to derive higher-order moments of turbulence in the boundary layer?…”

Initiation of convection over the Black Forest mountains during COPS IOP15a

“…The University of Basilicata Raman Lidar system (BASIL: Di Girolamo et al, 2009) was deployed at Supersite R. It measures temperature and water-vapour mixing ratio based on the application of the rotational (Di Girolamo et al, 2004) and rotovibrational Raman lidar techniques (Whiteman, 2003;Whiteman et al, 2006), respectively, in the ultraviolet region. The data used in this article were integrated over 15 minutes and have a vertical resolution for water vapour and temperature of 150 m and 300 m, respectively, and a precision for water vapour of less than 5% at 2 km and around 20% at 4 km (Bhawar et al, 2011) and for temperature of 1 K up to 4 km.…”