Attenuating the Absorption Contribution on $${C_{n^{2}}}$$ Estimates with a Large-Aperture Scintillometer

Solignac, Pierre; Brut, Aurore; Selves, Jean-Louis; Béteille, Jean-Pierre; Gastellu-Etchegorry, Jean-Philippe

doi:10.1007/s10546-011-9692-3

Cited by 10 publications

(6 citation statements)

References 23 publications

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“…Similarly, C 2 M can be obtained from the imaginary part of the AERISP (C 2 n, Im ). Although the LAS was widely used to measure the sensible heat flux along the propagation path, only the high-frequency part of the light intensity fluctuation could be provided, and the low-frequency light intensity was often discarded (Solignac et al, 2012). Thus, a specially designed LAS (see details in Sect.…”

Section: R M Yuan Et Al: a New Methods For Estimating Aerosol Mass mentioning

confidence: 99%

A new method for estimating aerosol mass flux in the urban surface layer using LAS technology

et al. 2016

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Abstract. Atmospheric aerosol greatly influences human health and the natural environment, as well as the weather and climate system. Therefore, atmospheric aerosol has attracted significant attention from society. Despite consistent research efforts, there are still uncertainties in understanding its effects due to poor knowledge about aerosol vertical transport caused by the limited measurement capabilities of aerosol mass vertical transport flux. In this paper, a new method for measuring atmospheric aerosol vertical transport flux is developed based on the similarity theory of surface layer, the theory of light propagation in a turbulent atmosphere, and the observations and studies of the atmospheric equivalent refractive index (AERI). The results show that aerosol mass flux can be linked to the real and imaginary parts of the atmospheric equivalent refractive index structure parameter (AERISP) and the ratio of aerosol mass concentration to the imaginary part of the AERI. The real and imaginary parts of the AERISP can be measured based on the lightpropagation theory. The ratio of the aerosol mass concentration to the imaginary part of the AERI can be measured based on the measurements of aerosol mass concentration and visibility. The observational results show that aerosol vertical transport flux varies diurnally and is related to the aerosol spatial distribution. The maximum aerosol flux during the experimental period in Hefei City was 0.017 mg m −2 s −1 , and the mean value was 0.004 mg m −2 s −1 . The new method offers an effective way to study aerosol vertical transport in complex environments.

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Section: R M Yuan Et Al: a New Methods For Estimating Aerosol Mass mentioning

confidence: 99%

A new method for estimating aerosol mass flux in the urban surface layer using LAS technology

et al. 2016

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“…Therefore, the light intensity variances induced by the real and imaginary parts can be detected separately at high frequencies and low frequencies from the sLAS measurements. The real part of AERISP be detected, and the low-frequency light intensity is often discarded (Solignac et al, 2012). Thus, a specially designed sLAS ( sea details in Section 3) is needed (Yuan et al, 2015).…”

Section: Measurement Methods 15mentioning

confidence: 99%

A new method for estimating aerosol mass flux in the urban surface layer by LAS

Yuan¹,

Luo²,

Sun³

et al. 2016

Preprint

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Abstract. Atmospheric aerosol has a great influence on human health and the natural environment as well as the weather and climate system. Therefore, atmospheric aerosol has attracted significant attention from the society as a whole. Despite consistent research efforts, there are still uncertainties in our understanding of its effects due to poor knowledge of aerosol vertical transport caused by our limited measurement capability of aerosol mass vertical transport flux. In this paper, a new method for measuring atmospheric aerosol vertical transport flux is developed based on the similarity theory of surface layer. The theoretical results show that aerosol mass flux can be linked to the real and imaginary parts of the atmospheric equivalent refractive index structure parameter (AERISP), and the ratio of aerosol mass concentration to the imaginary part of the atmospheric equivalent refractive index (AERI). The real and imaginary parts of AERISP can be measured based on the light propagation theory. The ratio of aerosol mass concentration to the imaginary part of AERI can be measured based on the measurements of aerosol mass concentration and visibility. The observational results show that aerosol vertical transport flux varies diurnally and is related to the aerosol spatial distribution. The maximum aerosol flux during the experimental period in Hefei City was 0.017 mgm−2s−1, and the mean value was 0.004 mgm−2s−1. The new method offers an effective way to study aerosol vertical transport over complex environments.

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“…Besides these applications, knowledge of the crosswind may be important for the quality of scintillometer data itself. Use of a dynamic bandpass filter has been suggested to account for the shift in frequency spectrum with crosswind (Solignac et al, 2012;Van Kesteren et al, 2015), as an inappropriate bandpass can artificially reduce Cn 2 . Whether related to the footprint, atmospheric conditions or basic principles of scintillometer measurement, it has been suggested that low and/or high crosswind speed has an impact on the accuracy of structure parameters and fluxes, particularly for two-wavelength systems (Evans, 2009;Ward et al, 2015b).…”

Section: Variable Wind Fieldmentioning

confidence: 99%

Scintillometry in urban and complex environments: a review

Ward

2017

Meas. Sci. Technol.

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Knowledge of turbulent exchange in complex environments is relevant to a wide range of hydrometeorological applications. Observations are required to improve understanding and inform model parameterisations but the very nature of complex environments presents challenges for measurements. Scintillometry offers several advantages as a technique for providing spatiallyintegrated turbulence data (structure parameters and fluxes), particularly in areas that would be impracticable to monitor using eddy covariance, such as across a valley, above a city or over heterogeneous landscapes. Despite much of scintillometry theory assuming flat, homogeneous surfaces and ideal conditions, over the last 20 years scintillometers have been deployed in increasingly complex locations, including urban and mountainous areas. This review draws together fundamental and applied research in complex environments, to assess what has been learnt, summarise the stateof-the-art and identify key areas for future research. Particular attention is given to evidence, or relative lack thereof, of the impact of complex environments on scintillometer data. Practical and theoretical considerations to account for the effects of complexity are discussed, with the aim of developing measurement capability towards more reliable and accurate observations in future. The usefulness of structure parameter measurements (in addition to fluxes, which must be derived using similarity theory) should not be overlooked, particularly when comparing or combining scintillometry with other measurement techniques and model simulations.

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Attenuating the Absorption Contribution on $${C_{n^{2}}}$$ Estimates with a Large-Aperture Scintillometer

Cited by 10 publications

References 23 publications

A new method for estimating aerosol mass flux in the urban surface layer using LAS technology

A new method for estimating aerosol mass flux in the urban surface layer using LAS technology

A new method for estimating aerosol mass flux in the urban surface layer by LAS

Scintillometry in urban and complex environments: a review

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