scholarly journals Profiling of CH<sub>4</sub> background mixing ratio in the lower troposphere with Raman lidar: a feasibility experiment

2018 ◽  
Author(s):  
Igor Veselovskii ◽  
Philippe Goloub ◽  
Qiaoyun Hu ◽  
Thierry Podvin ◽  
David N. Whiteman ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Elastic Scattering ◽  
Nd:Yag Laser ◽  
Counting Rate ◽  
Photon Counting ◽  
Lower Troposphere ◽  
Free Troposphere ◽  
Mixing Ratio ◽  
Raman Lidar ◽  
Additional Control

Abstract. We present the results of methane profiling in the lower troposphere using LILAS Raman lidar from Lille University observatory platform (France). The lidar is based on a tripled Nd:YAG laser and nighttime profiling up to 4000 m with 100 m height resolution is possible for methane. Agreement between measured the photon counting rate in the CH4 Raman channel in the free troposphere and numerical simulations for a typical CH4 background mixing ratio (2 ppm) confirms that CH4 Raman scattering is observed. Within the planetary boundary layer, an increase of the CH4 mixing ratio, up to a factor of 2, is observed. Different possible interfering factors, such as leakage of the elastic signal and aerosol fluorescence have been taken into consideration. Tests using backscattering from clouds confirmed that the filters in the Raman channel provide sufficient rejection of elastic scattering. The measured methane profiles do not correlate with aerosol backscattering, which corroborates the hypothesis that, in the PBL, not aerosol fluorescence but CH4 is observed. However, the fluorescence contribution cannot be completely excluded and, for future measurements, we plan to install an additional control channel close to 393 nm where no strong Raman lines exist and only fluorescence can be observed.

scholarly journals Profiling of CH<sub>4</sub> background mixing ratio in the lower troposphere with Raman lidar: a feasibility experiment

2019 ◽  
Vol 12 (1) ◽  
pp. 119-128 ◽  
Author(s):  
Igor Veselovskii ◽  
Philippe Goloub ◽  
Qiaoyun Hu ◽  
Thierry Podvin ◽  
David N. Whiteman ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Elastic Scattering ◽  
Planetary Boundary Layer ◽  
Counting Rate ◽  
Photon Counting ◽  
Lower Troposphere ◽  
Free Troposphere ◽  
Mixing Ratio ◽  
Raman Lidar ◽  
Additional Control

Abstract. We present the results of methane profiling in the lower troposphere using LILAS Raman lidar from the Lille University observatory platform (France). The lidar is based on a frequency-tripled Nd:YAG laser, and nighttime profiling up to 4000 with 100 m height resolution is possible for methane. Agreement between the measured photon-counting rate in the CH4 Raman channel in the free troposphere and numerical simulations for a typical CH4 background mixing ratio (2 ppm) confirms that CH4 Raman scattering is detected. The mixing ratio is calculated from the ratio of methane (395.7 nm) and nitrogen (386.7 nm) Raman backscatters, and within the planetary boundary layer, an increase of the CH4 mixing ratio, up to a factor of 2, is observed. Different possible interfering factors, such as leakage of the elastic signal and aerosol fluorescence, have been taken into consideration. Tests using backscattering from clouds confirmed that the filters in the Raman channel provide sufficient rejection of elastic scattering. The measured methane profiles do not correlate with aerosol backscattering, which corroborates the hypothesis that, in the planetary boundary layer, not aerosol fluorescence but CH4 is observed. However, the fluorescence contribution cannot be completely excluded and, for future measurements, we plan to install an additional control channel close to 393 nm, where no strong Raman lines exist and only fluorescence can be observed.

scholarly journals Potential of Raman Lidar for Profiling of Methane Mixing Ratio in the Lower Troposphere

2020 ◽  
Vol 237 ◽  
pp. 03024
Author(s):  
Igor Veselovskii ◽  
Philippe Goloub ◽  
Qiaoyun Hu ◽  
Thierry Podvin ◽  
Mikhail Korenskiy
Keyword(s):  
Boundary Layer ◽  
Temporal Resolution ◽  
Nd:Yag Laser ◽  
Resolution Enhancement ◽  
Lower Troposphere ◽  
Free Troposphere ◽  
Mixing Ratio ◽  
Raman Lidar ◽  
Night Time

The results of methane profiling in the lower troposphere by Raman lidar from Lille University observatory platform (France), are presented. The use of powerful DPSS tripled Nd:YAG laser allowed profiling of methane background mixing ratio of 2 ppm in the night time up to 4000 m with 100 m height and 1 hour temporal resolution. Enhancement of CH4 mixing ratio inside the boundary layer comparing to the free troposphere values was observed.

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

2021 ◽  
Author(s):  
Diego Lange ◽  
Andreas Behrendt ◽  
Volker Wulfmeyer
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Data Assimilation ◽  
Inversion Layer ◽  
Lower Troposphere ◽  
Statistical Uncertainty ◽  
Temperature Profiles ◽  
Free Troposphere ◽  
Earth System ◽  
Raman Lidar

&lt;p&gt;We present the Atmospheric Raman Temperature and Humidity Sounder (ARTHUS), a new tool for observations in the atmospheric boundary layer and lower free troposphere during daytime and nighttime with very high resolution up to the turbulence scale, high accuracy and precision, and very short latency and illustrate its performance with new measurements examples. ARTHUS measurements resolve the strength of the inversion layer at the planetary boundary layer top, elevated lids in the free troposphere, and turbulent fluctuations in water vapor and temperature, simultaneously (Lange et al., 2019). In addition to thermodynamic variables, ARTHUS provides also independent profiles of the particle backscatter coefficient and the particle extinction coefficient from the rotational Raman signals at 355 nm with much better resolution than a conventional vibrational Raman lidar.&lt;/p&gt;&lt;p&gt;The observation of atmospheric moisture and temperature profiles is essential for the understanding and prediction of earth system processes. These are fundamental components of the global and regional energy and water cycles, they determine the radiative transfer through the atmosphere, and are critical for the cloud formation and precipitation (Wulfmeyer, 2015). Also, as confirmed by case studies, the assimilation of high-quality, lower tropospheric WV and T profiles results in a considerable improvement of the skill of weather forecast models particularly with respect to extreme events.&lt;/p&gt;&lt;p&gt;Very stable and reliable performance was demonstrated during more than 3000 hours of operation experiencing a huge variety of weather conditions, including seaborne operation during the EUREC4A campaign (Bony et al., 2017, Stevens et al., 2020). ARTHUS provides temperature profiles with resolutions of 10-60 s and 7.5-100 m vertically in the lower free troposphere. During daytime, the statistical uncertainty of the WV mixing ratio is &lt;2 % in the lower troposphere for resolutions of 5 minutes and 100 m. Temperature statistical uncertainty is &lt;0.5 K even up to the middle troposphere. Consequently, ARTHUS fulfills the stringent WMO breakthrough requirements on nowcasting and very short-range forecasting (see www. wmo&amp;#8208;sat.info/oscar/observingrequirements).&lt;/p&gt;&lt;p&gt;This performance serves very well the next generation of very fast rapid-update-cycle data assimilation systems. Ground-based stations and networks can be set up or extended for climate monitoring, verification of weather, climate and earth system models, data assimilation for improving weather forecasts.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;References:&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;Bony et al., 2017, https://doi.org/10.1007/s10712-017-9428-0&lt;/p&gt;&lt;p&gt;Lange et al., 2019, https://doi.org/10.1029/2019GL085774&lt;/p&gt;&lt;p&gt;Stevens et al. 2020, submitted to ESSD&lt;/p&gt;&lt;p&gt;Wulfmeyer et al., 2015, doi:10.1002/2014RG000476&lt;/p&gt;

Two months of measurements with an autonomous thermodynamic Raman lidar in Lindenberg

2021 ◽  
Author(s):  
Diego Lange Vega ◽  
Andreas Behrendt ◽  
Volker Wulfmeyer
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Inversion Layer ◽  
Measurement Range ◽  
High Accuracy ◽  
Free Troposphere ◽  
Raman Lidar ◽  
Backscatter Coefficient ◽  
Geophysical Research ◽  
Turbulence Scale

&lt;p&gt;Between 15 July 2020 and 19 September 2021, the Atmospheric Raman Temperature and Humidity Sounder (ARTHUS) collected data at the Lindenberg Observatory of the Deutscher Wetterdienst (DWD), including temperature and water vapor mixing ratio with a high temporal and range resolution.&lt;/p&gt; &lt;p&gt;During the operation period, very stable 24/7 operation was achieved, and ARTHUS demonstrated that is capable to observe the atmospheric boundary layer and lower free troposphere during both daytime and nighttime up to the turbulence scale, with high accuracy and precision, and very short latency. During nighttime, the measurement range increases even up to the tropopause and lower stratosphere.&lt;/p&gt; &lt;p&gt;ARTHUS measurements resolve the strength of the inversion layer at the planetary boundary layer top, elevated lids in the free troposphere, and turbulent fluctuations in water vapor and temperature, simultaneously (Lange et al., 2019, Wulfmeyer et al., 2015). In addition to thermodynamic variables, ARTHUS provides also independent profiles of the particle backscatter coefficient and the particle extinction coefficient from the rotational Raman signals at 355 nm with much better resolution than a conventional vibrational Raman lidar.&lt;/p&gt; &lt;p&gt;At the conference, highlights of the measurements will be presented. Furthermore, the statistics of more than 150 comparisons with local radiosondes will be presented which confirm the high accuracy of the temperature and moisture measurements of ARTHUS.&lt;/p&gt; &lt;p&gt;&lt;strong&gt;&lt;em&gt;Acknowledgements&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt; &lt;p&gt;The development of ARTHUS was supported by the Helmholtz Association of German Research Centers within the project Modular Observation Solutions for Earth Systems (MOSES). The measurements in Lindenberg were funded by DWD.&lt;/p&gt; &lt;p&gt;&lt;strong&gt;&lt;em&gt;References &lt;/em&gt;&lt;/strong&gt;&lt;/p&gt; &lt;p&gt;Lange, D., Behrendt, A., and Wulfmeyer, V. (2019). Compact operational tropospheric water vapor and temperature Raman lidar with turbulence resolution. &lt;em&gt;Geophysical Research Letters&lt;/em&gt;, 46. https://doi.org/10.1029/2019GL085774&lt;/p&gt; &lt;p&gt;Wulfmeyer, V., R. M. Hardesty, D. D. Turner, A. Behrendt, M. P. Cadeddu, P. Di Girolamo, P. Schl&amp;#252;ssel, J. Van Baelen, and F. Zus (2015), A review of the remote sensing of lower tropospheric thermodynamic profiles and its indispensable role for the understanding and the simulation of water and energy cycles, &lt;em&gt;Rev. Geophys.&lt;/em&gt;, 53,819&amp;#8211;895, doi:10.1002/2014RG000476&lt;/p&gt;

scholarly journals Aircraft validation of Aura Tropospheric Emission Spectrometer retrievals of HDO / H<sub>2</sub>O

2014 ◽  
Vol 7 (9) ◽  
pp. 3127-3138 ◽  
Author(s):  
R. L. Herman ◽  
J. E. Cherry ◽  
J. Young ◽  
J. M. Welker ◽  
D. Noone ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Standard Deviation ◽  
Lower Troposphere ◽  
Temporal Variations ◽  
Observation Error ◽  
Free Troposphere ◽  
Data Set ◽  
Airborne Measurements

Abstract. The EOS (Earth Observing System) Aura Tropospheric Emission Spectrometer (TES) retrieves the atmospheric HDO / H2O ratio in the mid-to-lower troposphere as well as the planetary boundary layer. TES observations of water vapor and the HDO isotopologue have been compared with nearly coincident in situ airborne measurements for direct validation of the TES products. The field measurements were made with a commercially available Picarro L1115-i isotopic water analyzer on aircraft over the Alaskan interior boreal forest during the three summers of 2011 to 2013. TES special observations were utilized in these comparisons. The TES averaging kernels and a priori constraints have been applied to the in situ data, using version 5 (V005) of the TES data. TES calculated errors are compared with the standard deviation (1σ) of scan-to-scan variability to check consistency with the TES observation error. Spatial and temporal variations are assessed from the in situ aircraft measurements. It is found that the standard deviation of scan-to-scan variability of TES δD is ±34.1‰ in the boundary layer and ± 26.5‰ in the free troposphere. This scan-to-scan variability is consistent with the TES estimated error (observation error) of 10–18‰ after accounting for the atmospheric variations along the TES track of ±16‰ in the boundary layer, increasing to ±30‰ in the free troposphere observed by the aircraft in situ measurements. We estimate that TES V005 δD is biased high by an amount that decreases with pressure: approximately +123‰ at 1000 hPa, +98‰ in the boundary layer and +37‰ in the free troposphere. The uncertainty in this bias estimate is ±20‰. A correction for this bias has been applied to the TES HDO Lite Product data set. After bias correction, we show that TES has accurate sensitivity to water vapor isotopologues in the boundary layer.

scholarly journals Temperature profiling of the atmospheric boundary layer with rotational Raman lidar during the HD(CP)<sup>2</sup> Observational Prototype Experiment

2015 ◽  
Vol 15 (5) ◽  
pp. 2867-2881 ◽  
Author(s):  
E. Hammann ◽  
A. Behrendt ◽  
F. Le Mounier ◽  
V. Wulfmeyer
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Temperature Gradient ◽  
Atmospheric Boundary Layer ◽  
Average Power ◽  
Mixing Ratio ◽  
Raman Lidar ◽  
Backscatter Signal ◽  
Low Background ◽  
Water Vapor Mixing Ratio

Abstract. The temperature measurements of the rotational Raman lidar of the University of Hohenheim (UHOH RRL) during the High Definition of Clouds and Precipitation for advancing Climate Prediction (HD(CP)2) Observation Prototype Experiment (HOPE) in April and May 2013 are discussed. The lidar consists of a frequency-tripled Nd:YAG laser at 355 nm with 10 W average power at 50 Hz, a two-mirror scanner, a 40 cm receiving telescope, and a highly efficient polychromator with cascading interference filters for separating four signals: the elastic backscatter signal, two rotational Raman signals with different temperature dependence, and the vibrational Raman signal of water vapor. The main measurement variable of the UHOH RRL is temperature. For the HOPE campaign, the lidar receiver was optimized for high and low background levels, with a novel switch for the passband of the second rotational Raman channel. The instrument delivers atmospheric profiles of water vapor mixing ratio as well as particle backscatter coefficient and particle extinction coefficient as further products. As examples for the measurement performance, measurements of the temperature gradient and water vapor mixing ratio revealing the development of the atmospheric boundary layer within 25 h are presented. As expected from simulations, a reduction of the measurement uncertainty of 70% during nighttime was achieved with the new low-background setting. A two-mirror scanner allows for measurements in different directions. When pointing the scanner to low elevation, measurements close to the ground become possible which are otherwise impossible due to the non-total overlap of laser beam and receiving telescope field of view in the near range. An example of a low-level temperature measurement is presented which resolves the temperature gradient at the top of the stable nighttime boundary layer 100 m above the ground.

Lidar measurements accuracy of the hydrofluoride molecules concentration in the atmospheric boundary layer

2020 ◽  
pp. 29-33
Author(s):  
V.E. Privalov ◽  
V.G. Shemanin
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Relative Error ◽  
Concentration Level ◽  
Photon Counting ◽  
Raman Lidar ◽  
Height Range ◽  
Lidar Measurements ◽  
Counting Mode ◽  
Photon Counting Mode

The Raman lidar measurements accuracy of hydrofluoride molecules in the atmospheric boundary layer has been estimated in the work at the concentration level of 1014 сm–3and higher in the height range up to 1,5 km in the synchronous photon counting mode. It is received that it can measure the studied molecules concentration at the level of 1,5∙1014 сm–3 with the concentration measurement relative error lesser than 25 % at the 405 nm wavelength and the ranging distance up to 500 m by such a lidar.

scholarly journals Lidar characterization of the Arctic atmosphere during ASTAR 2007: four cases studies of boundary layer, mixed-phase and multi-layer clouds

2010 ◽  
Vol 10 (6) ◽  
pp. 2847-2866 ◽  
Author(s):  
A. Lampert ◽  
C. Ritter ◽  
A. Hoffmann ◽  
J.-F. Gayet ◽  
G. Mioche ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Case Studies ◽  
Airborne Lidar ◽  
Mixed Phase ◽  
Spherical Particles ◽  
The Arctic ◽  
Free Troposphere ◽  
Atmospheric Conditions ◽  
Raman Lidar ◽  
Tropospheric Aerosol

Abstract. During the Arctic Study of Tropospheric Aerosol, Clouds and Radiation (ASTAR), which was conducted in Svalbard in March and April 2007, tropospheric Arctic clouds were observed with two ground-based backscatter lidar systems (micro pulse lidar and Raman lidar) and with an airborne elastic lidar. In the time period of the ASTAR 2007 campaign, an increase in low-level cloud cover (cloud tops below 2.5 km) from 51% to 65% was observed above Ny-Ålesund. Four different case studies of lidar cloud observations are analyzed: With the ground-based Raman lidar, a layer of spherical particles was observed at an altitude of 2 km after the dissolution of a cloud. The layer probably consisted of small hydrated aerosol (radius of 280 nm) with a high number concentration (around 300 cm−3) at low temperatures (−30 °C). Observations of a boundary layer mixed-phase cloud by airborne lidar and concurrent airborne in situ and spectral solar radiation sensors revealed the localized process of total glaciation at the boundary of different air masses. In the free troposphere, a cloud composed of various ice layers with very different optical properties was detected by the Raman lidar, suggesting large differences of ice crystal size, shape and habit. Further, a mixed-phase double layer cloud was observed by airborne lidar in the free troposphere. Local orography influenced the evolution of this cloud. The four case studies revealed relations of cloud properties and specific atmospheric conditions, which we plan to use as the base for numerical simulations of these clouds.

Demonstration Measurements of Water Vapor, Cirrus Clouds, and Carbon Dioxide Using a High-Performance Raman Lidar

2007 ◽  
Vol 24 (8) ◽  
pp. 1377-1388 ◽  
Author(s):  
David N. Whiteman ◽  
Kurt Rush ◽  
Igor Veselovskii ◽  
Martin Cadirola ◽  
Joseph Comer ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Boundary Layer ◽  
Water Vapor ◽  
High Performance ◽  
Cirrus Clouds ◽  
Mixing Ratio ◽  
Raman Lidar ◽  
Cloud Optical Depth ◽  
Temporal And Spatial ◽  
Water Vapor Mixing Ratio

Abstract Profile measurements of atmospheric water vapor, cirrus clouds, and carbon dioxide using the Raman Airborne Spectroscopic lidar (RASL) during ground-based, upward-looking tests are presented here. These measurements improve upon any previously demonstrated using Raman lidar. Daytime boundary layer profiling of water vapor mixing ratio up to an altitude of approximately 4 km under moist, midsummer conditions is performed with less than 5% random error using temporal and spatial resolution of 2 min and 60–210 m, respectively. Daytime cirrus cloud optical depth and extinction-to-backscatter ratio measurements are made using a 1-min average. The potential to simultaneously profile carbon dioxide and water vapor mixing ratio through the boundary layer and extending into the free troposphere during the nighttime is also demonstrated.

scholarly journals Tethered balloon-borne aerosol measurements: seasonal and vertical variations of aerosol constituents over Syowa Station, Antarctica

2013 ◽  
Vol 13 (3) ◽  
pp. 8153-8211
Author(s):  
K. Hara ◽  
K. Osada ◽  
T. Yamanouchi
Keyword(s):  
Boundary Layer ◽  
Relative Abundance ◽  
Lower Troposphere ◽  
Sea Salt ◽  
Heterogeneous Reactions ◽  
Aerosol Sampling ◽  
Free Troposphere ◽  
Tethered Balloon ◽  
Syowa Station ◽  
Salt Fractionation

Abstract. Tethered balloon-borne aerosol measurements were conducted at Syowa Station, Antarctica during the 46th Japanese Antarctic expedition (2005–2006). Direct aerosol sampling was operated from near the surface to the lower free troposphere (approximately 2500 m) using a balloon-borne aerosol impactor. Individual aerosol particles were analyzed using a scanning electron microscope equipped with an energy dispersive X-ray spectrometer. Seasonal and vertical features of aerosol constituents and their mixing states were investigated. Results show that sulfate particles were dominant in the boundary layer and lower free troposphere in the summer, whereas sea-salt particles were dominant during winter–spring. Minerals, MgSO4, and sulfate containing K were identified as minor aerosol constituents in both boundary layer and free troposphere over Syowa Station. Although sea-salt particles were dominant during winter–spring, the relative abundance of sulfate particles increased in the boundary layer when air masses fell from the free troposphere over the Antarctic coast and continent. Sea-salt particles were modified considerably through heterogeneous reactions with SO42−, CH3SO3−, and their precursors during the summer, and were modified slightly through heterogeneous reactions with NO3− and its precursors. During winter–spring, sea-salt modification was insignificant, particularly in the cases of high relative abundance of sea-salt particles and higher number concentrations. In August, NO3− and its precursors contributed greatly to sea-salt modification over Syowa Station. Because of the occurrence of sea-salt fractionation on sea-ice, Mg-rich sea-salt particles were identified during April–November. In contrast, Mg-free sea-salt particles and slightly Mg-rich sea-salt particles co-existed in the lower troposphere during summer. Thereby, Mg separation can proceed by sea-salt fractionation during summer in Antarctic regions.

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