scholarly journals Toronto Water Vapor Lidar Inter-Comparison Campaign

2020 ◽  
Vol 12 (19) ◽  
pp. 3165
Author(s):  
Zen Mariani ◽  
Noah Stanton ◽  
James Whiteway ◽  
Raisa Lehtinen
Keyword(s):  
Water Vapor ◽  
Weather Conditions ◽  
Horizontal Displacement ◽  
Raman Lidar ◽  
Night Time ◽  
Operational Program ◽  
Comparison Field ◽  
Atmospheric Backscatter ◽  
Good Agreement

This study presents comparisons between vertical water vapor profile measurements from a Raman lidar and a new pre-production broadband differential absorption lidar (DIAL). Vaisala’s novel DIAL system operates autonomously outdoors and measures the vertical profile of water vapor within the boundary layer 24 h a day during all weather conditions. Eight nights of measurements in June and July 2018 were used for the Toronto water vapor lidar inter-comparison field campaign. Both lidars provided reliable atmospheric backscatter and water vapor profile measurements. Comparisons were performed during night-time observations only, when the York Raman lidar could measure the water vapor profile. The purpose was to validate the water vapor profile measurements retrieved by the new DIAL system. The results indicate good agreement between the two lidars, with a mean difference (DIAL–Raman) of 0.17 ± 0.14 g/kg. There were two main causes for differences in their measurements: horizontal displacement between the two lidar sites (3.2 km) and vertical gradients in the water vapor profile. A case study analyzed during the campaign demonstrates the ability for both lidars to measure sudden changes and large gradients in the water vapor’s vertical structure due to a passing frontal system. These results provide an initial validation of the DIAL’s measurements and its ability to be implemented as part of an operational program.

scholarly journals Spectrally-Resolved Raman Lidar to Measure Atmospheric Three-Phase Water Simultaneously

2020 ◽  
Vol 237 ◽  
pp. 06017
Author(s):  
Fuchao Liu ◽  
Fan Yi
Keyword(s):  
Water Vapor ◽  
Raman Spectra ◽  
Weather Conditions ◽  
Cloud Microphysics ◽  
Raman Lidar ◽  
Atmospheric Water ◽  
Three Phase ◽  
Phase Water ◽  
Spectrally Resolved ◽  
Ice Water

We report on a spectrally-resolved Raman lidar that can simultaneously profile backscattered Raman spectrum signals from water vapor, water droplets and ice crystals as well as aerosol fluorescence in the atmosphere. The lidar emits a 354.8-nm ultraviolet laser radiation and samples echo signals in the 393.0-424.0 nm wavelength range with a 1.0-nm spectral resolution. A spectra decomposition method is developed to retrieve fluorescence spectra, water vapor Raman spectra and condensed (liquid and/or ice) water Raman spectra successively. Based on 8 different clear-sky nighttime measurement results, the entire atmospheric water vapor Raman spectra are for the first time obtained by lidar. The measured normalized water vapor Raman spectra are nearly invariant and can serve as background reference for atmospheric water phase state identification under various weather conditions. For an ice virga event, it’s found the extracted condensed water Raman spectra are highly similar in shape to theoretical ice water Raman spectra reported by Slusher and Derr (1975). In conclusion, the lidar provides an effective way to measure three-phase water simultaneously in the atmosphere and to study of cloud microphysics as well as interaction between aerosols and clouds.

scholarly journals Inter-comparison of ABL height estimates from different profiling sensors and models in the framework of HyMeX-SOP1

2021 ◽  
Author(s):  
Donato Summa ◽  
Fabio Madonna ◽  
Noemi Franco ◽  
Bendetto De Rosa ◽  
Paolo Di Girolamo
Keyword(s):  
Friction Velocity ◽  
Hydrological Cycle ◽  
Weather Conditions ◽  
Raman Lidar ◽  
Lidar System ◽  
Combined Application ◽  
Radiosonde Station ◽  
Atmospheric Dynamic ◽  
Thermodynamic Variables ◽  
Good Agreement

Abstract. This paper reports results from an inter-comparison effort involving different sensors/techniques used to measure the Atmospheric Boundary Layer (ABL) height. The effort took place in the framework of the first Special Observing Period of the Hydrological cycle of the Mediterranean Experiment (HyMeX-SOP1). Elastic backscatter and rotational Raman signals collected by the Raman lidar system BASIL were used to determine the ABL height and characterize its internal structure. These techniques were compared with co-located measurements from a wind profiler and radiosondes and with ECMWF-ERA5 data. In the effort we consider radiosondes launched in the proximity of the lidar site, as well as radiosondes launched from the closest radiosonde station included in the Integrated Global Radiosonde archive (IGRA). The inter-comparison effort considers data from October 2012. Results reveal a good agreement between the different approaches, with values of the correlation coefficient R2 in the range 0.52 to 0.94. Results clearly reveals that the combined application of different techniques to distinct sensors’ and model datasets allow getting accurate and cross-validated estimates of the ABL height over a variety of weather conditions. Furthermore, correlations between the ABL height and other atmospheric dynamic and thermodynamic variables as CAPE, friction velocity and relative humidity are also assessed to infer possible mutual dependences.

scholarly journals Validation of the Water Vapor Profiles of the Raman Lidar at the Maïdo Observatory (Reunion Island) Calibrated with Global Navigation Satellite System Integrated Water Vapor

Atmosphere ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 713 ◽  
Author(s):  
Hélène Vérèmes ◽  
Guillaume Payen ◽  
Philippe Keckhut ◽  
Valentin Duflot ◽  
Jean-Luc Baray ◽  
...  
Keyword(s):  
Water Vapor ◽  
Global Navigation Satellite System ◽  
Satellite System ◽  
Navigation Satellite ◽  
Reunion Island ◽  
Raman Lidar ◽  
Réunion Island ◽  
Global Navigation ◽  
Global Navigation Satellite ◽  
Good Agreement

The Maïdo high-altitude observatory located in Reunion Island (21 ∘ S, 55.5 ∘ E) is equipped with the Lidar1200, an innovative Raman lidar designed to measure the water vapor mixing ratio in the troposphere and the lower stratosphere, to perform long-term survey and processes studies in the vicinity of the tropopause. The calibration methodology is based on a GNSS (Global Navigation Satellite System) IWV (Integrated Water Vapor) dataset. The lidar water vapor measurements from November 2013 to October 2015 have been calibrated according to this methodology and used to evaluate the performance of the lidar. The 2-year operation shows that the calibration uncertainty using the GNSS technique is in good agreement with the calibration derived using radiosondes. During the MORGANE (Maïdo ObservatoRy Gaz and Aerosols NDACC Experiment) campaign (Reunion Island, May 2015), CFH (Cryogenic Frost point Hygrometer) radiosonde and Raman lidar profiles are compared and show good agreement up to 22 km asl; no significant biases are detected and mean differences are smaller than 9% up to 22 km asl.

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

2006 ◽  
Vol 23 (2) ◽  
pp. 170-183 ◽  
Author(s):  
D. N. Whiteman ◽  
B. Demoz ◽  
G. Schwemmer ◽  
B. Gentry ◽  
P. Di Girolamo ◽  
...  
Keyword(s):  
Water Vapor ◽  
Case Studies ◽  
The United States ◽  
Back Trajectory ◽  
Cirrus Cloud ◽  
Raman Lidar ◽  
Cloud Optical Depth ◽  
Back Trajectory Analysis ◽  
Cloud Modeling

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.

scholarly journals First-Year Operation of a New Water Vapor Raman Lidar at the JPL Table Mountain Facility, California

2008 ◽  
Vol 25 (8) ◽  
pp. 1454-1462 ◽  
Author(s):  
Thierry Leblanc ◽  
I. Stuart McDermid ◽  
Robin A. Aspey
Keyword(s):  
Water Vapor ◽  
Current System ◽  
First Year ◽  
Raman Lidar ◽  
Upper Troposphere ◽  
Mixing Ratios ◽  
Table Mountain ◽  
Lidar Measurements ◽  
Better Than ◽  
Good Agreement

Abstract A new water vapor Raman lidar was recently built at the Table Mountain Facility (TMF) of the Jet Propulsion Laboratory (JPL) in California and more than a year of routine 2-h-long nighttime measurements 4–5 times per week have been completed. The lidar was designed to reach accuracies better than 5% anywhere up to 12-km altitude, and with the capability to measure water vapor mixing ratios as low as 1 to 10 ppmv near the tropopause and in the lower stratosphere. The current system is not yet fully optimized but has already shown promising results as water vapor profiles have been retrieved up to 18-km altitude. Comparisons with Vaisala RS92K radiosondes exhibit very good agreement up to at least 10 km. They also revealed a wet bias in the lidar profiles (or a dry bias in the radiosonde profiles), increasing with altitude and becoming significant near 10 km and large when approaching the tropopause. This bias cannot be explained solely by well-known too-dry measurements of the RS92K in the upper troposphere and therefore must partly originate in the lidar measurements. Excess signal due to residual fluorescence in the lidar receiver components is among the most likely candidates and is subject to ongoing investigation.

scholarly journals Water Vapor Mixing Ratio Distribution Inversion by Raman Lidar in Beijing

2020 ◽  
Vol 237 ◽  
pp. 06020
Author(s):  
SiQi Yu ◽  
Dong Liu ◽  
JiWei Xu ◽  
ZhenZhu Wang ◽  
DeCheng Wu ◽  
...  
Keyword(s):  
Water Vapor ◽  
Radiosonde Data ◽  
Mixing Ratio ◽  
Raman Lidar ◽  
Ratio Distribution ◽  
Water Vapor Mixing Ratio ◽  
Detection Instrument ◽  
Active Detection ◽  
The Vertical Distribution ◽  
Good Agreement

Water Aerosol Raman Lidar-II is an active detection instrument with high temporal and spatial resolution at Nanjiao observation station, and that could continuous water vapor mixing ratio (WVMR) measurements. WVMR profiles inversion from lidar data and water ratio retrieved from radiosonde data are in good agreement. The statistical results of the vertical distribution of WVMR indicate that WVMR seasonal mean distribution is consistent with precipitation. In addition, WVMR in Nanjiao station is related to total cloud cover.

scholarly journals Raman Lidar for Meteorological Observations, RALMO – Part I: Instrument description

2012 ◽  
Vol 5 (5) ◽  
pp. 6867-6914 ◽  
Author(s):  
T. S. Dinoev ◽  
V. B. Simeonov ◽  
Y. F. Arshinov ◽  
S. M. Bobrovnikov ◽  
P. Ristori ◽  
...  
Keyword(s):  
Water Vapor ◽  
Optical Design ◽  
Time Range ◽  
Lidar Measurement ◽  
Raman Lidar ◽  
Night Time ◽  
Measurement Capability ◽  
Vertical Range ◽  
Federal Institute ◽  
Institute Of Technology

Abstract. A new Raman lidar for unattended, round the clock measurement of vertical water vapor profiles for operational use by the MeteoSwiss has been developed during the past years by the Swiss Federal Institute of Technology- Lausanne. The lidar uses narrow-field-of-view, narrow-band configuration, a UV laser, and four 30 cm in diameter mirrors, fiber-coupled to a grating polychromator. The optical design allows water vapor retrieval from the incomplete overlap region without instrument-specific range-dependent corrections. The daytime vertical range covers the mid-troposphere, whereas the night-time range extends to the tropopause. The near range coverage is extended down to 100 m AGL by the use of an additional fiber in one of the telescopes. This paper describes the system layout and technical realization. Day and night time lidar profiles compared to Vaisala RS-92 and Snow White® profiles and a six-day-continuous observation are presented as an illustration of the lidar measurement capability.

Aerosol and Water Vapor Raman Lidar System at CEILAP, Buenos Aires, Argentina. Case Study: November 07, 2006.

2008 ◽  
Author(s):  
Lidia Ana Otero ◽  
Pablo Roberto Ristori ◽  
Eduardo Jaime Quel ◽  
Niklaus Ursus Wetter ◽  
Jaime Frejlich
Keyword(s):  
Water Vapor ◽  
Buenos Aires ◽  
Raman Lidar ◽  
Lidar System

Sediment transport under dry weather conditions in a small sewer system

1998 ◽  
Vol 37 (1) ◽  
pp. 155-162
Author(s):  
Flemming Schlütter ◽  
Kjeld Schaarup-Jensen
Keyword(s):  
Sediment Transport ◽  
Field Data ◽  
Field Measurements ◽  
Weather Conditions ◽  
Sewer System ◽  
Transport Models ◽  
Sewer Systems ◽  
Combined Sewer ◽  
Initial Results

Increased knowledge of the processes which govern the transport of solids in sewers is necessary in order to develop more reliable and applicable sediment transport models for sewer systems. Proper validation of these are essential. For that purpose thorough field measurements are imperative. This paper renders initial results obtained in an ongoing case study of a Danish combined sewer system in Frejlev, a small town southwest of Aalborg, Denmark. Field data are presented concerning estimation of the sediment transport during dry weather. Finally, considerations on how to approach numerical modelling is made based on numerical simulations using MOUSE TRAP (DHI 1993).

Sign in / Sign up

Export Citation Format

Share Document