High-power Ti:sapphire laser at 820 nm for scanning ground-based water–vapor differential absorption lidar

Wagner, Gerd; Behrendt, Andreas; Wulfmeyer, Volker; Späth, Florian; Schiller, Max

doi:10.1364/ao.52.002454

Cited by 46 publications

(43 citation statements)

References 75 publications

(111 reference statements)

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“…It is planned to extend the investigation of CBL characteristics in future studies also by combining the UHOH RRL data with humidity and wind observations from water vapor DIAL Wagner et al, 2013;Muppa et al, 2015) and Doppler lidar. Furthermore, also the scanning capability of the UHOH RRL will be used in the future to collect data closer to the ground and even the surface layer in order to investigate heterogeneities over different terrain.…”

Section: Discussionmentioning

confidence: 99%

Profiles of second- to fourth-order moments of turbulent temperature fluctuations in the convective boundary layer: first measurements with rotational Raman lidar

et al. 2015

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Abstract. The rotational Raman lidar (RRL) of the University of Hohenheim (UHOH) measures atmospheric temperature profiles with high resolution (10 s, 109 m). The data contain low-noise errors even in daytime due to the use of strong UV laser light (355 nm, 10 W, 50 Hz) and a very efficient interference-filter-based polychromator. In this paper, the first profiling of the second-to fourth-order moments of turbulent temperature fluctuations is presented. Furthermore, skewness profiles and kurtosis profiles in the convective planetary boundary layer (CBL) including the interfacial layer (IL) are discussed. The results demonstrate that the UHOH RRL resolves the vertical structure of these moments. The data set which is used for this case study was collected in western Germany (50 • 53 50.56 N, 6 • 27 50.39 E; 110 m a.s.l.) on 24 April 2013 during the Intensive Observations Period (IOP) 6 of the HD(CP) 2 (High-Definition Clouds and Precipitation for advancing Climate Prediction) Observational Prototype Experiment (HOPE). We used the data between 11:00 and 12:00 UTC corresponding to 1 h around local noon (the highest position of the Sun was at 11:33 UTC). First, we investigated profiles of the total noise error of the temperature measurements and compared them with estimates of the temperature measurement uncertainty due to shot noise derived with Poisson statistics. The comparison confirms that the major contribution to the total statistical uncertainty of the temperature measurements originates from shot noise. The total statistical uncertainty of a 20 min temperature measurement is lower than 0.1 K up to 1050 m a.g.l. (above ground level) at noontime; even for single 10 s temperature profiles, it is smaller than 1 K up to 1020 m a.g.l. Autocovariance and spectral analyses of the atmospheric temperature fluctuations confirm that a temporal resolution of 10 s was sufficient to resolve the turbulence down to the inertial subrange. This is also indicated by the integral scale of the temperature fluctuations which had a mean value of about 80 s in the CBL with a tendency to decrease to smaller values towards the CBL top. Analyses of profiles of the second-, third-, and fourth-order moments show that all moments had peak values in the IL around the mean top of the CBL which was located at 1230 m a.g.l. The maximum of the variance profile in the IL was 0.39 K 2 with 0.07 and 0.11 K 2 for the sampling error and noise error, respectively. The third-order moment (TOM) was not significantly different from zero in the CBL but showed a negative peak in the IL with a minimum of −0.93 K 3 and values of 0.05 and 0.16 K 3 for the sampling and noise errors, respectively. The fourth-order moment (FOM) and kurtosis values throughout the CBL were not significantly different to those of a Gaussian distribution. Both showed also maxima in the IL but these were not statistically significant taking the measurement uncertainties into account. We conclude that these measurements permit the validation of large eddy simulation results and the...

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Section: Discussionmentioning

confidence: 99%

Profiles of second- to fourth-order moments of turbulent temperature fluctuations in the convective boundary layer: first measurements with rotational Raman lidar

et al. 2015

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“…A temperature rotational Raman lidar (TRRL) measured temperature profiles Hammann et al, 2015;Radlach et al, 2008) and a water vapour DIAL measured absolute humidity profiles Späth et al, 2016;Wagner et al, 2013). In contrast to the Raman lidar technique, the DIAL technique, which is based on the alternating emission of laser pulses at frequencies strongly and weakly absorbed by water vapour, does not require calibration.…”

Section: Hambach Supersitementioning

confidence: 99%

The HD(CP)<sup>2</sup> Observational Prototype Experiment (HOPE) – an overview

et al. 2017

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Abstract. The HD(CP) 2 Observational Prototype Experiment (HOPE) was performed as a major 2-month field experiment in Jülich, Germany, in April and May 2013, followed by a smaller campaign in Melpitz, Germany, in September 2013. HOPE has been designed to provide an observational dataset for a critical evaluation of the new German community atmospheric icosahedral non-hydrostatic (ICON) model at the scale of the model simulations and further to provide information on land-surface-atmospheric boundary layer exchange, cloud and precipitation processes, as well as sub-grid variability and microphysical properties that are subject to parameterizations. HOPE focuses on the onset of clouds and precipitation in the convective atmospheric boundary layer. This paper summarizes the instrument set-ups, the intensive observation periods, and example results from both campaigns.HOPE-Jülich instrumentation included a radio sounding station, 4 Doppler lidars, 4 Raman lidars (3 of them providePublished by Copernicus Publications on behalf of the European Geosciences Union. temperature, 3 of them water vapour, and all of them particle backscatter data), 1 water vapour differential absorption lidar, 3 cloud radars, 5 microwave radiometers, 3 rain radars, 6 sky imagers, 99 pyranometers, and 5 sun photometers operated at different sites, some of them in synergy. The HOPEMelpitz campaign combined ground-based remote sensing of aerosols and clouds with helicopter-and balloon-based in situ observations in the atmospheric column and at the surface.HOPE provided an unprecedented collection of atmospheric dynamical, thermodynamical, and micro-and macrophysical properties of aerosols, clouds, and precipitation with high spatial and temporal resolution within a cube of approximately 10 × 10 × 10 km 3 . HOPE data will significantly contribute to our understanding of boundary layer dynamics and the formation of clouds and precipitation. The datasets have been made available through a dedicated data portal.First applications of HOPE data for model evaluation have shown a general agreement between observed and modelled boundary layer height, turbulence characteristics, and cloud coverage, but they also point to significant differences that deserve further investigations from both the observational and the modelling perspective.

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“…Concerning (1), the laser transmitter is based on an injection-seeding technology. Wagner et al (2013) demonstrated that the UHOH DIAL transmitter has excellent spectral properties so that remaining systematic errors are <3 % throughout the troposphere. With respect to (2), detailed sensitivity analyses of systematic errors in the derivation of the absorption cross-section profile led to an error <1.3 % (with uncertainties of 1 K in temperature and 1 hPa in pressure, respectively) for measurements in the lower troposphere.…”

Section: The Uhoh Water Vapour Dial Systemmentioning

confidence: 99%

“…We present results obtained with recent data from our ground-based, scanning water vapour DIAL system (Wagner et al 2013). Whereas it is also possible to derive higher-order moments with water vapour Raman lidar, Wulfmeyer et al (2010) and Turner et al (2014) demonstrated that the noise level in daytime turbulence profiles is much larger than for water vapour DIAL.…”

Section: Introductionmentioning

confidence: 99%

Turbulent Humidity Fluctuations in the Convective Boundary Layer: Case Studies Using Water Vapour Differential Absorption Lidar Measurements

Muppa

Behrendt

Späth

et al. 2015

Boundary-Layer Meteorol

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Turbulent humidity fluctuations in the convective boundary layer (CBL) under clear-sky conditions were investigated by deriving moments up to fourth-order. Highresolution humidity measurements were collected with a water vapour differential absorption lidar system during the HD(CP) 2 Observational Prototype Experiment (HOPE). Two cases, both representing a well-developed CBL around local noon, are discussed. While the first case (from the intensive observation period (IOP) 5 on 20 April 2013) compares well with what is considered typical CBL behaviour, the second case (from IOP 6 on 24 April 2013) shows a number of non-typical characteristics. Both cases show similar capping inversions and wind shear across the CBL top. However, a major difference between both cases is the advection of a humid layer above the CBL top during IOP 6. While the variance profile of IOP 5 shows a maximum at the interfacial layer, two variance peaks are observed near the CBL top for IOP 6. A marked difference can also be seen in the third-order moment and skewness profiles: while both are negative (positive) below (above) the CBL top for IOP 5, the structure is more complex for IOP 6. Kurtosis is about three for IOP 5, whereas for IOP 6, the distribution is slightly platykurtic. We believe that the entrainment of an elevated moist layer into the CBL is responsible for the unusual findings for IOP 6, which suggests that it is important to consider the structure of residual humidity layers entrained into the CBL.

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High-power Ti:sapphire laser at 820 nm for scanning ground-based water–vapor differential absorption lidar

Cited by 46 publications

References 75 publications

Profiles of second- to fourth-order moments of turbulent temperature fluctuations in the convective boundary layer: first measurements with rotational Raman lidar

Profiles of second- to fourth-order moments of turbulent temperature fluctuations in the convective boundary layer: first measurements with rotational Raman lidar

The HD(CP)<sup>2</sup> Observational Prototype Experiment (HOPE) – an overview

Turbulent Humidity Fluctuations in the Convective Boundary Layer: Case Studies Using Water Vapour Differential Absorption Lidar Measurements

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High-power Ti:sapphire laser at 820 nm for scanning ground-based water–vapor differential absorption lidar

Cited by 46 publications

References 75 publications

Profiles of second- to fourth-order moments of turbulent temperature fluctuations in the convective boundary layer: first measurements with rotational Raman lidar

Profiles of second- to fourth-order moments of turbulent temperature fluctuations in the convective boundary layer: first measurements with rotational Raman lidar

The HD(CP)&lt;sup&gt;2&lt;/sup&gt; Observational Prototype Experiment (HOPE) – an overview

Turbulent Humidity Fluctuations in the Convective Boundary Layer: Case Studies Using Water Vapour Differential Absorption Lidar Measurements

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The HD(CP)<sup>2</sup> Observational Prototype Experiment (HOPE) – an overview