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Proceedings ArticleDOI

High resolution Raman lidar for simultaneous measurement of temperature and water vapor in the lower atmosphere at a coastal station, Trivandrum

22 Dec 2006-Vol. 6409
TL;DR: In this paper, the Vibrational Raman Lidar was used for measuring atmospheric temperature and water vapor using N2 and H 2 O spectra of N2 spectra.
Abstract: This work reports the development and preliminary results of the Vibrational Raman lidar at a coastal station, Trivandrum (8°33'N, 77°E). A Raman lidar technique for measuring atmospheric temperature and water vapor using vibrational Raman spectra of N2 and H 2 O are discussed in detail. Interference filters at 607 and 660nm of 1nm band- width are used in the Raman lidar channel. Nighttime temperature and water vapor profiles are obtained from 1-5km in the lower atmosphere. Lidar water vapor profiles are in good agreement with the Regional Model data. The variation in the temperature profiles may be due to the indirect aerosol effect in the lower atmosphere.
Citations
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Journal ArticleDOI
TL;DR: The Purple Crow Lidar (PCL) as discussed by the authors is a monostatic laser radar which is capable of measuring temperature from 10 to 110 km altitude, as well as water vapour in the troposphere and stratosphere.
Abstract: The Purple Crow Lidar (PCL) is a large power-aperture product monostatic laser radar which until 2010 was located at the Delaware Observatory (42°52′N, 81°23′W, 225 m elevation above sea level) near the campus of the University of Western Ontario. It is capable of measuring temperature from 10 to 110 km altitude, as well as water vapour in the troposphere and stratosphere. We use upper tropospheric and stratospheric vibrational Raman N2 backscatter-derived temperatures to form a climatology for the years 1999 to 2007 from 10 to 40 km attitude. The lidar temperatures are validated using nearby radiosonde measurements from Detroit and Buffalo. The measured temperatures show good agreement with the radiosonde soundings. An agreement of ±1 K is found during the summer months and ±2.5 K during the winter months, validating the calibration of the lidar to within the geophysical variability of the measurements. Comparison between the PCL measurements and the Committee on Space Research International Refe...

3 citations

Proceedings ArticleDOI
03 Jul 2009
TL;DR: A measuring system is established, with a Digital Delay/Pulse Generator as the chief component, which is not usually used as a measuring instrument, which could reach about 50ps and the compensating method is provided to improve the positioning accuracy of the lidar system.
Abstract: Pure Rotational Raman Lidar is a recently developed method for atmospheric temperature detection. Since the Raman-scattering-signals are very weak, the photon-counting method is employed, which could be achieved by using a multiscaler. Time delays, which exist among the trigger channel and the two count channels of the multiscaler, will affect the corresponding relationship between the detected signals and the actual altitudes where the signals are returned, so it is necessary to make some compensation. However, it is difficult to measure the time delays with traditional instruments such as oscillograph, for there is no access to the final internal trigger signal or count signals. In this paper, a measuring system is established, with a Digital Delay/Pulse Generator as the chief component, which is not usually used as a measuring instrument. The measurement precision could reach about 50ps. Meanwhile, the compensating method is also provided to improve the positioning accuracy of the lidar system.
01 Oct 2008
TL;DR: In this paper, the vibrational Raman scattered signals of N 2 and H 2O were used for the measurement of atmospheric water vapour and aerosol extinction in the lower troposphere.
Abstract: Near simultaneous measurement of atmospheric aerosol and water vapour is described in this paper, making use of the Nd: YAG laser based multiwavelength lidar system, designed and developed in-house at Space Physics Laboratory, Vikram Sarabhai Space Centre, Trivandrum, India. In the present study, the vibrational Raman scattered signals of N 2 and H 2O were used for the measurement of atmospheric water vapour and aerosol extinction. Nighttime water vapour profiles are obtained in the 1-6 km altitude regions in the lower troposphere. Necessary aerosol corrections to water vapour profiles are also done. Lidar derived water vapour profiles are compared with the profiles calculated from High resolution Regional Weather Model (HRM) available during the same period.
References
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BookDOI
01 Jan 1976

400 citations

Journal ArticleDOI
TL;DR: A modification of the DIAL technique, high-spectral-resolution DIAL avoids errors that are due to Doppler-broadened Rayleigh backscatter and permits simultaneous water-vapor and wind measurements with the same system.
Abstract: A comprehensive formulation of the differential absorption lidar (DIAL) methodology is presented that explicitly includes details of the spectral distributions of both the transmitted and the backscattered light. The method is important for high-accuracy water-vapor retrievals and in particular for temperature measurements. Probability estimates of the error that is due to Doppler-broadened Rayleigh scattering based on an extended experimental data set are presented, as is an analytical treatment of errors that are due to averaging in the nonlinear retrieval scheme. System performance requirements are derived that show that water-vapor retrievals with an accuracy of better than 5% and temperature retrievals with an accuracy of better than 1 K in the entire troposphere are feasible if the error that results from Rayleigh-Doppler correction can be avoided. A modification of the DIAL technique, high-spectral-resolution DIAL avoids errors that are due to Doppler-broadened Rayleigh backscatter and permits simultaneous water-vapor and wind measurements with the same system.

126 citations


"High resolution Raman lidar for sim..." refers background in this paper

  • ...Nitrogen and water vapor signals, signal to noise ratio-SNR, percentage of error in the water vapor mixing ratio are presented in figure (6,7, 8)....

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  • ...4000 D 3500 - <3000 0500 F 0000 1500 -50 -40 -30 -00 -10 0 10 00 30 40 % of error Figure (6): Nitrogen and water vapor signals Figure (7): Nitrogen and Water vapor SNR Figure (8): Percentage of error in Water Vapor Mixing Ratio Proc. of SPIE Vol. 6409 64090M-7 Temperature profile 300 320 340 360 380 Temperature (K) Tsmpsrsturs preflis Temperature (K) Water vapor profiles obtained by Raman Lidar system are consistent with HRM model values....

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  • ...Figure (7): Nitrogen and Water vapor SNR Figure (8): Percentage of error in Water Vapor Mixing Ratio...

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Journal ArticleDOI
TL;DR: An improved method by which temperature can be derived from a combination of the Rayleigh -Mie return at 351-nm lidar channels and the Raman nitrogen return at 382-nm coffin channels is reported on.
Abstract: The NASA Goddard Space Flight Center stratospheric ozone lidar system has the capability of collecting both Rayleigh–Mie and Raman backscatter data simultaneously at a number of wavelengths. Here we report on an improved method by which temperature can be derived from a combination of the Rayleigh–Mie return at 351-nm lidar channels and the Raman nitrogen return at 382-nm lidar channels. We also examine some common techniques by which temperatures are retrieved from lidar data. Finally, we show results obtained in 1995 during two Network for the Detection of Stratospheric Change intercomparison campaigns at Lauder, New Zealand and Mauna Loa, Hawaii.

41 citations


"High resolution Raman lidar for sim..." refers background in this paper

  • ...Figure (2) shows the range corrected signals corresponding to nitrogen and water vapor have saturation problem and for this reason the water vapor inversion was made above 1....

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  • ...Figure (2): Range corrected nitrogen signal...

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DOI
01 Jan 2004
TL;DR: In this article, a multi-wavelength LIDAR-based remote sensing technique was used for monitoring atmospheric compounds and processes, including water vapor mixing ratio and relative humidity in the upper troposphere.
Abstract: The impact of human activities on the global climate may lead to large disruptions of the economic, social and political status quo in the middle and long term Understanding the dynamics of the Earth's climate is thus of paramount importance and one of the major scientific challenges of our time The estimation of the relative contribution of the many components (interacting each other) of the Earth's climate system requires observation and continuous monitoring of various atmospheric physical and chemical parameters Temperature, water vapor and greenhouse gases concentration, aerosol and clouds loads, and atmospheric dynamics are parameters of particular importance in this respect The quantification of the anthropogenic influence on the dynamics of these above-mentioned parameters is of crucial importance nowadays but still affected by significant uncertainties In the present context of these huge uncertainties in our understanding of how these different atmospheric compounds contribute to the radiative forcing, the research presented in this report is related to the following topics: Development of lidar-based remote sensing techniques for monitoring atmospheric compounds and processes Aerosols – cirrus – contrails optical properties up to the tropopause Water vapor mixing ratio and relative humidity estimation in the upper troposphere Temperature profiling in the upper troposphere-lower stratosphere Characterization of the long-range transported mineral aerosols (ie Saharan dust outbreaks) Planetary boundary layer-upper troposphere exchanges (ie August 2003 heatwave effect) In the above research frames, the development and application of measurement techniques for the monitoring of climate-change parameters, this work refers to the implementation of a multi-wavelength LIDAR1 system (JFJ - LIDAR)2 at the International Scientific Station of Jungfraujoch (ISSJ, 46°33' N, 7°59' E, at 3580 m ASL- above sea level) The JFJ3 station is situated above the planetary boundary layer (PBL) almost all year long and is located in a mountain pass linking the Swiss plateau to the North with the Rhone Valley to the South through the Aletsch glacier corridor Measurements with the JFF-LIDAR system provide regular vertical and horizontal remote sensing of water vapor, temperature, and optical properties (backscatter and extinction coefficients) of aerosols, cirrus clouds and contrails in the upper troposphere (UT)4 The lidar system is based on the laser emission at 355, 532 and 1064 nm and on subsequent detection of both elastic (Mie) and inelastic (Raman) atmospheric backscatter light The backscattering collected radiation is precisely: the elastic at 355, 532 and 1064 nm; the rotational-vibrational Raman radiation from nitrogen at 387 nm, and from water vapor at 407 nm as well as the pure rotational nitrogen/oxygen Raman excited at 532 nm The depolarization of the initially linearly polarized radiation was also detected at 532 nm and it was use to distinguish between water and ice contents in cirrus clouds, but also it may reveal long-range transported mineral aerosols such as Saharan dust Profiles of backscatter and extinction coefficients of aerosols-cirrus-contrails, needed for estimation of the radiative balance of the atmosphere, are derived from elastic and Raman light scattering processes, or through a combination of both, using devoted algorithms and software developed within this research Data gathered from routine measurements are statistically analyzed and interpreted in comparison with similar measurements obtained from colocated techniques Optical and microphysical properties of a typical contrail were studied The UT water vapor mixing ratio profiles are estimated from the ratio of 407 nm and 387 nm Raman radiation excited by 355 nm Upon appropriate calibration, real time water vapor mixing ratio profiles derived from LIDAR measurements are found in good agreement with the closest radiosounding techniques, and co-located measurements such as the GPS5 and sun photometer based measurements The water vapor profiles, combined with simultaneous temperature profiles taken from atmospheric models, radiosounding or, more realistically, based on the pure rotational Raman technique, were used for the estimation of relative humidity profiles which allow the identification of UT super-saturation regions Air temperature profiles were obtained up to the lower stratosphere using the backscatter of pure rotational Raman radiation excited by 532 nm These first results compare well to simultaneous regional radiosounding measurements, and follow standard atmospheric models The pure rotational Raman backscatter was also used for determining absolute extinction and the lidar ratio for cirrus clouds Based on the JFJ-LIDAR measurements, supported by co-located and regional measurements, the research presents also in detail two case studies related to climate problematic: The first concerns the tracking of a Saharan dust outbreak (SDO) and the derivation of its optical properties The second study refers to the analysis of the evolution and consequences of the high altitudes planetary boundary layer (PBL)6 convection during the August 2003 heat - wave episode The results presented within this research provide a promising basis for extending these JFJ-LIDAR observations from the upper troposphere into the stratosphere by using the existent astronomic telescope ( 15 times increased sensitivity) and a new ( 3 times more powerful) laser source Consequently DIAL7 technique for measuring the stratospheric ozone will be developed and implemented in the near future at JFJ Future challenges include also JFJ-LIDAR remote control operation and the ability of real time obtained atmospheric calibrated profiles (ie optical properties of aerosols-cirruscontrails, water vapor, temperature and ozone) --------------------1 LIDAR – LIght Detection And Ranging 2 JFJ-LIDAR is the acronym used here for Jungfraujoch multi-wavelength LIDAR system 3 JFJ is the abbreviation for Jungfraujoch 4 UT will be used as abbreviation for upper troposphere (from 3600 m ASL to the tropopause atmospheric region) 5 GPS is the acronym for Global Positioning System 6 PBL - planetary boundary layer – its top is usually situated under the altitude of the JFJ station (ie 3600m ASL) 7 DIAL - is the acronym coming from DIfferential Absorption Lidar

25 citations


"High resolution Raman lidar for sim..." refers background in this paper

  • ...Figure (1): Schematic diagram of the Multi Wavelength Raman Lidar...

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