Automated compact mobile Raman lidar for water vapor measurement: instrument description and validation by comparison with radiosonde, GNSS, and high-resolution objective analysis

Abstract

We developed an automated compact mobile Raman lidar (MRL) system for measuring the vertical distribution of the water vapor mixing ratio (w) in the lower troposphere, which has an affordable cost and is easy to operate. The MRL was installed in a small trailer for easy deployment and can start measurement in a few hours, and it is capable of unattended operation for several months. We describe the MRL system and present validation results obtained by comparing the MRL-measured data with collocated radiosonde, Global Navigation Satellite System (GNSS), and high-resolution objective analysis data. The comparison results showed that MRL-derived w agreed within 10 % (rootmean-square difference of 1.05 g kg −1 ) with values obtained by radiosonde at altitude ranges between 0.14 and 1.5 km in the daytime and between 0.14 and 5-6 km at night in the absence of low clouds; the vertical resolution of the MRL measurements was 75-150 m, their temporal resolution was less than 20 min, and the measurement uncertainty was less than 30 %. MRL-derived precipitable water vapor values were similar to or slightly lower than those obtained by GNSS at night, when the maximum height of MRL measurements exceeded 5 km. The MRL-derived w values were at most 1 g kg −1 (25 %) larger than local analysis data. A total of 4 months of continuous operation of the MRL system demonstrated its utility for monitoring water vapor distributions in the lower troposphere.Published by Copernicus Publications on behalf of the European Geosciences Union.

Ice-nucleating particle versus ice crystal number concentration in altocumulus and cirrus embedded in Saharan dust: A closure study

“…However, the successful closure studies are encouraging and corroborate that our way to estimate and combine INPC and ICNC observations can be regarded as a constructive contribution to cloud research, especially to investigations of the role and overall impact of aerosols on cloud and precipitation formation. As an outlook, in future closure studies, we may include the next generation of powerful water vapor differential absorption lidars (DIALs) or Raman lidars to obtain temporally and 10 vertically highly resolved water vapor and relative humidity profiles in cirrus and transparent altocumulus layers (Leblanc et al, 2012;Reichardt et al, 2012;Späth et al, 2016;Sakai et al, 2019) as well as information on liquid-water and ice-water content (Wang et al, 2004;Sakai et al, 2013;Reichardt, 2014). We may also integrate radar wind profilers in our cloud studies to obtain detailed updraft and downdraft observations in the cloid top regions (Bühl et al, 2015;Radenz et al, 2018), and even lidar techniques for quantification of mineral dust concentrations within the ice clouds (Tatarov and Sugimoto, 2005;Müller 15 et al, 2010;Tatarov et al, 2011).…”

Ice-nucleating particle versus ice crystal number concentrationin altocumulus and cirrus layers embedded in Saharan dust:a closure study

“…Cirrus uncinus belongs to the synoptic cirrus category (Sassen, 2002). These ice clouds form in situ in the upper troposphere in response to a variety of weather disturbances.…”

“…As an outlook and to reduce the number of critical assumptions in our closure methodology as discussed in Sect. 4, we may include the next generation of powerful water vapor differential absorption lidars (DIALs) or Raman lidars to obtain temporally and vertically highly resolved water vapor and relative-humidity profiles in cirrus and transparent altocumulus layers (Leblanc et al, 2012;Reichardt et al, 2012;Späth et al, 2016;Sakai et al, 2019) as well as information on liquid water and ice water content (Wang et al, 2004;Sakai et al, 2013;Reichardt, 2014) in future closure studies. We may also integrate radar wind profilers in our cloud studies to obtain detailed updraft and downdraft observations in the cloud top regions Radenz et al, 2018) and even lidar techniques for the quantification of mineral dust concentrations within the ice clouds (Tatarov and Sugimoto, 2005;Müller et al, 2010;Tatarov et al, 2011).…”

Compact Operational Tropospheric Water Vapor and Temperature Raman Lidar with Turbulence Resolution

“…Passive remote sensing systems intrinsically lack the ability to resolve vertical structures in the order of a few hundred meter or less since their number of independent measurement points is limited (e.g., Wulfmeyer et al, 2016). Thus, several active remote sensing systems based on the lidar technology were developed in recent years to obtain operational or quasi-operational WV observations-and partly including also observations of T. In case of WV, the existing systems include the DIAL system of the National Center for Atmospheric Research (NCAR) (Spuler et al, 2015;Weckwerth et al, 2016), the the Raman lidar ofthe Jet Propulsion Laboratory (JPL) (Leblanc et al, 2012), and the Raman lidar of the Meteorological Research Institute (MRI) (Sakai et al, 2019). Both WV and T profiles are provided by the following lidar systems: the lidar of the Atmospheric Radiation Measurement (ARM) programSouthern Great Plains (SGP) site (Goldsmith et al, 1998;Newsom et al, 2013), RAMSES (Reichardt et al, 2012), and Raman LIDAR for Meteorological Observation (RALMO) lidar (Dinoev et al, 2013).…”