Doppler Lidar Estimation of Mixing Height Using Turbulence, Shear, and Aerosol Profiles

Tucker, S. C.; Senff, Christoph J.; Weickmann, A. M.; Brewer, W. Alan; Banta, Robert M.; Sandberg, Scott P.; Law, D. C.; Hardesty, R. Michael

doi:10.1175/2008jtecha1157.1

Cited by 192 publications

(181 citation statements)

References 44 publications

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“…Muppa et al, 2016;Van Weverberg et al, 2016); it has also been used to remove random noise from routine measurements of variance, including within the stable boundary layer (e.g. Tucker et al, 2009;Pal et al, 2013;Schween et al, 2014;Bonin et al, 2015). While this methodology has been used within many studies, to the authors' knowledge there are no in-depth evaluations of corrected and uncorrected turbulence statistics, using the (Lenschow et al, 2000) technique, of any quantity measured by a lidar against in situ observations.…”

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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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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“…As measurements of vertical velocity variance are a direct measurement of the turbulent mixing process, they are the most useful data for the estimation of mixing height during convective conditions (Tucker et al, 2009). This estimation of mixing height also agrees closely with that derived from aerosol backscatter, which may be considered an indicator of the vertical extent of mixing.…”

Section: Model Description and Parametrisationmentioning

confidence: 99%

Simulating atmospheric composition over a South-East Asian tropical rainforest: performance of a chemistry box model

et al. 2010

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Abstract. Atmospheric composition and chemistry above tropical rainforests is currently not well established, particularly for south-east Asia. In order to examine our understanding of chemical processes in this region, the performance of a box model of atmospheric boundary layer chemistry is tested against measurements made at the top of the rainforest canopy near Danum Valley, Malaysian Borneo. Multivariate optimisation against ambient concentration measurements was used to estimate average canopy-scale emissions for isoprene, total monoterpenes and nitric oxide. The excellent agreement between estimated values and measured fluxes of isoprene and total monoterpenes provides confidence in the overall modelling strategy, and suggests that this method may be applied where measured fluxes are not available, assuming that the local chemistry and mixing are adequately understood. The largest contributors to the optimisation cost function at the point of best-fit are OH (29%), NO (22%) and total peroxy radicals (27%). Several factors affect the modelled VOC chemistry. In particular concentrations of methacrolein (MACR) and methyl-vinyl ketone (MVK) are substantially overestimated, and the hydroxyl radical (OH)Correspondence to: T. A. M. Pugh (t.pugh@lancs.ac.uk) concentration is substantially underestimated; as has been seen before in tropical rainforest studies. It is shown that inclusion of dry deposition of MACR and MVK and wet deposition of species with high Henry's Law values substantially improves the fit of these oxidised species, whilst also substantially decreasing the OH sink. Increasing OH production arbitrarily, through a simple OH recycling mechanism , adversely affects the model fit for volatile organic compounds (VOCs). Given the constraints on isoprene flux provided by measurements, a substantial decrease in the rate of reaction of VOCs with OH is the only remaining option to explain the measurement/model discrepancy for OH. A reduction in the isoprene+OH rate constant of 50%, in conjunction with increased deposition of intermediates and some modest OH recycling, is able to produce both isoprene and OH concentrations within error of those measured. Whilst we cannot rule out an important role for missing chemistry, particularly in areas of higher isoprene flux, this study demonstrates that the inadequacies apparent in box and global model studies of tropical VOC chemistry may be more strongly influenced by representation of detailed physical and micrometeorological effects than errors in the chemical scheme.

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“…At Hornisgrinde, z i and its standard deviation was additionally estimated from lidar observations, using the strong reduction of the aerosol backscatter signal for the detection of z i (e.g. Tucker et al, 2009). Note that the lidar cannot detect boundary-layer heights below 400 m above ground level (agl), because this level is the instrument's lowest measurement height.…”

Section: The Dependence Of Cbl Conditions On Surface Fluxes and Over mentioning

confidence: 99%

The dependence of convection‐related parameters on surface and boundary‐layer conditions over complex terrain

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Köhler

Barthlott

et al. 2010

Quart J Royal Meteoro Soc

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The field campaign 'Convective and Orographically-induced Precipitation Study' (COPS) was performed in south-western Germany and eastern France in summer 2007. Within the COPS context this study focused on the process chain of soil moisture, surface fluxes, conditions of the convective boundary layer (CBL), and convection-related parameters.The results were different for valley and mountain sites. Only in the Rhine valley did the ratios of sensible and latent heat to the net radiation at the surface, H 0 /Q 0 and E 0 /Q 0 respectively, reveal a weak dependence on soil moisture. H 0 /Q 0 was lower and E 0 /Q 0 was higher at higher soil moisture. The correlation of the diurnal increase of the equivalent potential temperature, e , with the energy supplied by H 0 and E 0 was found to be lower for higher surface inhomogeneity. Furthermore, only a weak dependence of the CBL depth on the sensible surface heat flux was found for valley sites and was non-existent for the mountain crest.The convective indices in the whole COPS domain were found to depend on e in the CBL. The absolute values of conditional and potential instability are not necessarily the decisive parameters for convection to occur, because highest instability was observed in the Rhine valley while convection was preferably initiated over the mountains. Convective inhibition (CIN) was positively correlated with the capping strength and negatively with the CBL height: the higher the CBL, the lower the upper threshold of CIN. The frequency of low CIN was higher in the Black Forest mountains than in the Rhine valley, which facilitates convection initiation over the mountain sites.

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Doppler Lidar Estimation of Mixing Height Using Turbulence, Shear, and Aerosol Profiles

Cited by 192 publications

References 44 publications

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

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

Simulating atmospheric composition over a South-East Asian tropical rainforest: performance of a chemistry box model

The dependence of convection‐related parameters on surface and boundary‐layer conditions over complex terrain

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