Independent measurements of Raman LIDAR water vapor calibration factor

2011 ◽  
Author(s):  
M.N. Calhoun ◽  
D.D. Venable ◽  
D.N. Whiteman
Keyword(s):  
Water Vapor ◽  
Calibration Factor ◽  
Raman Lidar

scholarly journals Diffuse sunlight based calibration of the water vapor channel in the upc raman lidar

2018 ◽  
Vol 176 ◽  
pp. 05035
Author(s):  
Constantino Muñoz-Porcar ◽  
Adolfo Comeron ◽  
Michaël Sicard ◽  
Ruben Barragan ◽  
David Garcia-Vizcaino ◽  
...  
Keyword(s):  
Water Vapor ◽  
Raman Scattering ◽  
Calibration Factor ◽  
Raman Lidar ◽  
Lidar System ◽  
System Parameters ◽  
Vapor Channel ◽  
Technical University

A method for determining the calibration factor of the water vapor channel of a Raman lidar, based on zenith measurements of diffuse sunlight and on assumptions regarding some system parameters and Raman scattering models, has been applied to the lidar system of Universitat Politècnica de Catalunya (UPC; Technical University of Catalonia, Spain). Results will be analyzed in terms of stability and comparison with typical methods relying on simultaneous radiosonde measurements.

scholarly journals Study and mitigation of calibration factor instabilities in a water vapor Raman lidar

2017 ◽  
Vol 10 (7) ◽  
pp. 2745-2758 ◽  
Author(s):  
Leslie David ◽  
Olivier Bock ◽  
Christian Thom ◽  
Pierre Bosser ◽  
Jacques Pelon
Keyword(s):  
Water Vapor ◽  
Lower Troposphere ◽  
Satellite System ◽  
Calibration Factor ◽  
Raman Lidar ◽  
Lidar System ◽  
Short Term ◽  
Term Stability ◽  
Water Vapor Mixing Ratio

Abstract. We have investigated calibration variations in the Rameau water vapor Raman lidar. This lidar system was developed by the Institut National de l'Information Géographique et Forestière (IGN) together with the Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS). It aims at calibrating Global Navigation Satellite System (GNSS) measurements for tropospheric wet delays and sounding the water vapor variability in the lower troposphere. The Rameau system demonstrated good capacity in retrieving water vapor mixing ratio (WVMR) profiles accurately in several campaigns. However, systematic short-term and long-term variations in the lidar calibration factor pointed to persistent instabilities. A careful testing of each subsystem independently revealed that these instabilities are mainly induced by mode fluctuations in the optic fiber used to couple the telescope to the detection subsystem and by the spatial nonuniformity of the photomultiplier photocathodes. Laboratory tests that replicate and quantify these instability sources are presented. A redesign of the detection subsystem is presented, which, combined with careful alignment procedures, is shown to significantly reduce the instabilities. Outdoor measurements were performed over a period of 5 months to check the stability of the modified lidar system. The calibration changes in the detection subsystem were monitored with lidar profile measurements using a common nitrogen filter in both Raman channels. A short-term stability of 2–3 % and a long-term drift of 2–3 % per month are demonstrated. Compared to the earlier Development of Methodologies for Water Vapour Measurement (DEMEVAP) campaign, this is a 3-fold improvement in the long-term stability of the detection subsystem. The overall water vapor calibration factors were determined and monitored with capacitive humidity sensor measurements and with GPS zenith wet delay (ZWD) data. The changes in the water vapor calibration factors are shown to be fairly consistent with the changes in the nitrogen calibration factors. The nitrogen calibration results can be used to correct the overall calibration factors without the need for additional water vapor measurements to within 1 % per month.

Lamp mapping technique for independent determination of the water vapor mixing ratio calibration factor for a Raman lidar system

2011 ◽  
Vol 50 (23) ◽  
pp. 4622 ◽  
Author(s):  
Demetrius D. Venable ◽  
David N. Whiteman ◽  
Monique N. Calhoun ◽  
Afusat O. Dirisu ◽  
Rasheen M. Connell ◽  
...  
Keyword(s):  
Water Vapor ◽  
Calibration Factor ◽  
Mapping Technique ◽  
Mixing Ratio ◽  
Raman Lidar ◽  
Lidar System ◽  
Independent Determination ◽  
Water Vapor Mixing Ratio

Narrow-band, narrow-field-of-view Raman lidar with combined day and night capability for tropospheric water-vapor profile measurements

1999 ◽  
Vol 38 (9) ◽  
pp. 1841 ◽  
Author(s):  
Scott E. Bisson ◽  
John E. M. Goldsmith ◽  
Mark G. Mitchell
Keyword(s):  
Water Vapor ◽  
Narrow Band ◽  
Field Of View ◽  
Raman Lidar

Raman lidar water vapor profiling over Warsaw, Poland

2017 ◽  
Vol 194 ◽  
pp. 258-267 ◽  
Author(s):  
Iwona S. Stachlewska ◽  
Montserrat Costa-Surós ◽  
Dietrich Althausen
Keyword(s):  
Water Vapor ◽  
Raman Lidar

scholarly journals A Satellite-Based Assessment of Upper-Tropospheric Water Vapor Measurements during AFWEX

2009 ◽  
Vol 48 (11) ◽  
pp. 2284-2294 ◽  
Author(s):  
Eui-Seok Chung ◽  
Brian J. Soden
Keyword(s):  
Water Vapor ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Raman Lidar ◽  
Test Bed ◽  
Upper Troposphere ◽  
Brightness Temperatures ◽  
Radiation Test ◽  
Humidity Measurements ◽  
Atmospheric Radiation Measurement

Abstract Consistency of upper-tropospheric water vapor measurements from a variety of state-of-the-art instruments was assessed using collocated Geostationary Operational Environmental Satellite-8 (GOES-8) 6.7-μm brightness temperatures as a common benchmark during the Atmospheric Radiation Measurement Program (ARM) First International Satellite Cloud Climatology Project (ISCCP) Regional Experiment (FIRE) Water Vapor Experiment (AFWEX). To avoid uncertainties associated with the inversion of satellite-measured radiances into water vapor quantity, profiles of temperature and humidity observed from in situ, ground-based, and airborne instruments are inserted into a radiative transfer model to simulate the brightness temperature that the GOES-8 would have observed under those conditions (i.e., profile-to-radiance approach). Comparisons showed that Vaisala RS80-H radiosondes and Meteolabor Snow White chilled-mirror dewpoint hygrometers are systemically drier in the upper troposphere by ∼30%–40% relative to the GOES-8 measured upper-tropospheric humidity (UTH). By contrast, two ground-based Raman lidars (Cloud and Radiation Test Bed Raman lidar and scanning Raman lidar) and one airborne differential absorption lidar agree to within 10% of the GOES-8 measured UTH. These results indicate that upper-tropospheric water vapor can be monitored by these lidars and well-calibrated, stable geostationary satellites with an uncertainty of less than 10%, and that correction procedures are required to rectify the inherent deficiencies of humidity measurements in the upper troposphere from these radiosondes.

scholarly journals A Lidar at Clermont-Ferrand—France to describe the boundary layer dynamics, aerosols, cirrus and tropospheric water vapor

2018 ◽  
Vol 176 ◽  
pp. 05047
Author(s):  
J.L. Baray ◽  
P. Fréville ◽  
N. Montoux ◽  
A. Chauvigné ◽  
D. Hadad ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Vertical Profiles ◽  
Raman Lidar ◽  
Tropospheric Aerosols ◽  
Boundary Layer Dynamics

A Rayleigh-Mie-Raman LIDAR provides vertical profiles of tropospheric variables at Clermont-Ferrand (France) since 2008, in order to describe the boundary layer dynamics, tropospheric aerosols, cirrus and water vapor. It is included in the EARLINET network. We performed hardware/software developments in order to upgrade the quality, calibration and improve automation. We present an overview of the system and some examples of measurements and a preliminary geophysical analysis of the data.

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.

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