Preliminary measurements with an automated compact differential absorption lidar for the profiling of water vapor

Machol, J. L.; Ayers, Tom; Schwenz, Karl T.; Koenig, Keith W.; Hardesty, R. Michael; Senff, Christoph J.; Krainak, Michael A.; Abshire, James B.; Bravo, Hector E.; Sandberg, Scott P.

doi:10.1364/ao.43.003110

Cited by 55 publications

(56 citation statements)

References 24 publications

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“…Specific DIAL systems were developed, e.g., near 720 nm (Bruneau et al, 2001;Wulfmeyer and Bösenberg, 1998), near 820 nm (Ismail and Browell, 1989;Ertel, 2004;Schiller et al, 2007;Vogelmann et al, 2008;Behrendt et al, 2009;Spuler et al, 2015), near 935 nm (Machol et al, 2004(Machol et al, , 2006Wirth et al, 2009;Fix et al, 2011), and near 1480 nm (Petrova-Mayor et al, 2008). The UHOH DIAL operates at wavelengths near 818 nm because this wavelength region can be reached well with a Ti:sapphire transmitter and offers a sufficiently large range of WV absorption cross sections (Wagner et al, 2011.…”

Section: Dial Methodologymentioning

confidence: 99%

3-D water vapor field in the atmospheric boundary layer observed with scanning differential absorption lidar

et al. 2016

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Abstract. High-resolution three-dimensional (3-D) water vapor data of the atmospheric boundary layer (ABL) are required to improve our understanding of land-atmosphere exchange processes. For this purpose, the scanning differential absorption lidar (DIAL) of the University of Hohenheim (UHOH) was developed as well as new analysis tools and visualization methods. The instrument determines 3-D fields of the atmospheric water vapor number density with a temporal resolution of a few seconds and a spatial resolution of up to a few tens of meters. We present three case studies from two field campaigns. In spring 2013, the UHOH DIAL was operated within the scope of the HD(CP) 2 Observational Prototype Experiment (HOPE) in western Germany. HD(CP) 2 stands for High Definition of Clouds and Precipitation for advancing Climate Prediction and is a German research initiative. Range-height indicator (RHI) scans of the UHOH DIAL show the water vapor heterogeneity within a range of a few kilometers up to an altitude of 2 km and its impact on the formation of clouds at the top of the ABL. The uncertainty of the measured data was assessed for the first time by extending a technique to scanning data, which was formerly applied to vertical time series. Typically, the accuracy of the DIAL measurements is between 0.5 and 0.8 g m −3 (or < 6 %) within the ABL even during daytime. This allows for performing a RHI scan from the surface to an elevation angle of 90 • within 10 min. In summer 2014, the UHOH DIAL participated in the Surface Atmosphere Boundary Layer Exchange (SABLE) campaign in southwestern Germany. Conical volume scans were made which reveal multiple water vapor layers in three dimensions. Differences in their heights in different directions can be attributed to different surface elevation. With low-elevation scans in the surface layer, the humidity profiles and gradients can be related to different land cover such as maize, grassland, and forest as well as different surface layer stabilities.

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Section: Dial Methodologymentioning

confidence: 99%

3-D water vapor field in the atmospheric boundary layer observed with scanning differential absorption lidar

et al. 2016

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“…This technique has been used in numerous studies to estimate second-and higher-order moments of water vapour from Raman lidars and differential absorption lidars (DIALs) (e.g. Machol et al, 2004;Wulfmeyer et al, 2010;Turner et al, 2014a, b), temperature from Raman lidar (e.g. Behrendt et al, 2015), ozone from a DIAL (e.g.…”

Section: Llnl Windcube V2mentioning

confidence: 99%

Improvement of vertical velocity statistics measured by a Doppler lidar through comparison with sonic anemometer observations

et al. 2016

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Abstract. Since turbulence measurements from Doppler lidars are being increasingly used within wind energy and boundary-layer meteorology, it is important to assess and improve the accuracy of these observations. While turbulent quantities are measured by Doppler lidars in several different ways, the simplest and most frequently used statistic is vertical velocity variance (w 2 ) from zenith stares. However, the competing effects of signal noise and resolution volume limitations, which respectively increase and decrease w 2 , reduce the accuracy of these measurements. Herein, an established method that utilises the autocovariance of the signal to remove noise is evaluated and its skill in correcting for volume-averaging effects in the calculation of w 2 is also assessed. Additionally, this autocovariance technique is further refined by defining the amount of lag time to use for the most accurate estimates of w 2 . Through comparison of observations from two Doppler lidars and sonic anemometers on a 300 m tower, the autocovariance technique is shown to generally improve estimates of w 2 . After the autocovariance technique is applied, values of w 2 from the Doppler lidars are generally in close agreement (R 2 ≈ 0.95 − 0.98) with those calculated from sonic anemometer measurements.

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“…The first demonstration of a diode-laser-based WV-DIAL was in 2004 by Machol et al which was capable of nighttime operation [9]. From 2009 to 2012 Nehrir et al significantly advanced the field, particularly with respect to transmitter design [10,11], and subsequently demonstrated the first diode-laser-based WV-DIAL capable of daytime measurements [12].…”

Section: Introductionmentioning

confidence: 99%

Advances in Diode-Laser-Based Water Vapor Differential Absorption Lidar

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Morley

et al. 2016

EPJ Web of Conferences

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An advanced diode-laser-based water vapor differential absorption lidar (WV-DIAL) has been developed. The next generation design was built on the success of previous diode-laser-based prototypes and enables accurate measurement of water vapor closer to the ground surface, in rapidly changing atmospheric conditions, and in daytime cloudy conditions up to cloud base. The lidar provides up to 1 min resolution, 150 m range resolved measurements of water vapor in a broad range of atmospheric conditions. A description of the instrument and results from its initial field test in 2014 are discussed.

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Preliminary measurements with an automated compact differential absorption lidar for the profiling of water vapor

Cited by 55 publications

References 24 publications

3-D water vapor field in the atmospheric boundary layer observed with scanning differential absorption lidar

3-D water vapor field in the atmospheric boundary layer observed with scanning differential absorption lidar

Improvement of vertical velocity statistics measured by a Doppler lidar through comparison with sonic anemometer observations

Advances in Diode-Laser-Based Water Vapor Differential Absorption Lidar

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