A Novel Lidar Ceilometer

Hey, Joshua Vande; Hey,

doi:10.1007/978-3-319-12613-5

Cited by 8 publications

(2 citation statements)

References 26 publications

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“…There exists a large variety of ways to define a cloud in terms of a remote sensing signal (Vande Hey, 2015). In this study the attenuated backscatter coefficient profile from the ceilometer at Flyger's Hut at Station Nord is used to determine the cloud cover quantities.…”

Section: Postprocessingmentioning

confidence: 99%

Observed and modelled cloud cover up to 6 km height at Station Nord in the high Arctic

Gryning

Batchvarova

Floors

et al. 2020

Intl Journal of Climatology

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We present results from an analyses of cloud cover based on profiles of the attenuated backscatter coefficient from an 8-year-long data series (July 2011-April 2019). The observations are carried out in the high Arctic by a ceilometer with a maximum range setting of 7.7 km from the Villum Research Station at Station Nord, Greenland. Results show that the hourly cloud cover turned out to follow a U-shaped rather than Gaussian-like distribution. Annual and seasonal cloud cover variation is illustrated. The cloud cover is larger during the autumn and winter as compared to summer and spring. The cloud cover exhibits a substantial variation from year to year without a clear trend. The cloud cover during spring is low and decreasing between 2012 and 2017. The cloud cover during the autumn of 2016 is lowest compared to the other years. The observed cloud cover is compared to the cloud cover provided in the ERA5 reanalysis dataset. The cloud cover for low clouds and medium clouds are combined to represent a total height of 6 km. Both the observed and modelled cloud cover is larger during winter as compared to summertime cloud cover. The measured reduction in the cloud cover for the autumn of 2016 is present in the reanalysis data as well but the measured low cloud cover during spring is not apparent in the reanalysis data. Because the cloud cover distribution is U-shaped rather than of a Gaussian nature, standard metrics are not applicable. We apply a generalized skill score that is developed for contingency tables or joint histograms. Three skill scores were calculated. It was found that for all three methods, skills for the predictability of the cloud cover by the ERA5 modelling is better for winter than summer and is poor during the spring.

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Section: Postprocessingmentioning

confidence: 99%

Observed and modelled cloud cover up to 6 km height at Station Nord in the high Arctic

Gryning

Batchvarova

Floors

et al. 2020

Intl Journal of Climatology

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“…Having obtained these parameters, and using theoretical data to obtain the profile of molecular extinction, we can couple them with our experimental lidar data to calculate the total backscatter coefficient profile through the backwards-integrating Fernald-Klett inversion [28], which is then used to obtain the total extinction coefficient profile, and the optical depth [29]:…”

Section: Astronomy Parameters Extinction and Backscatter Coefficientsmentioning

confidence: 99%

A Turbulence-Oriented Approach to Retrieve Various Atmospheric Parameters Using Advanced Lidar Data Processing Techniques

et al. 2019

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The article is aimed at presenting a semi-empirical model coded and computed in the programming language Python, which utilizes data gathered with a standard biaxial elastic lidar platform in order to calculate the altitude profiles of the structure coefficients of the atmospheric refraction index C N 2 ( z ) and other associated turbulence parameters. Additionally, the model can be used to calculate the PBL (Planetary Boundary Layer) height, and other parameters typically employed in the field of astronomy. Solving the Fernard–Klett inversion by correlating sun-photometer data obtained through our AERONET site with lidar data, it can yield the atmospheric extinction and backscatter profiles α ( z ) and β ( z ) , and thus obtain the atmospheric optical depth. Finally, several theoretical notions of interest that utilize the solved parameters are presented, such as approximated relations between C N 2 ( z ) and the atmospheric temperature profile T ( z ) , and between the scintillation of backscattered lidar signal and the average wind speed profile U ( z ) . These obtained profiles and parameters also have several environmental applications that are connected directly and indirectly to human health and well-being, ranging from understanding the transport of aerosols in the atmosphere and minimizing the errors in measuring it, to predicting extreme, and potentially-damaging, meteorological events.

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Design and fabrication by selective laser melting of a LIDAR reflective unit using metal matrix composite material

Boschetto

Bottini

Macera

2023

Int J Adv Manuf Technol

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The selective laser melting is an additive manufacturing technology able to directly fabricate full dense metal part from a virtual model. The geometrical complexity degree of freedom allows the implementation to several industrial applications such as the laser imaging detection and ranging systems. A key component of this system is the reflective unit produced with traditional technology (surface with ribs) with optimized geometry for lightweight, which must be further lightened while continuing to meet functional requirements. Aim of this work is to reach these goals by using an integrated product/process methodology which considers all the fabrication steps. A complete redesign allowed to exploit the additive manufacturing advantages of a metal matrix composite based on AA 2000 series combined with a high content of ceramic. The increased mechanical properties, such as the tensile strength of 484 MPa and Young modulus of 96GPa, combined with a lattice structure empowered the SLM capability. The component was validated via finite element method simulation focused on the most critical polishing operation. Results on static and dynamic analysis showed the 25% lightened mirror satisfies the requirements. The testing on the physical prototype confirmed the enhanced mechanical properties and the interferometric measurement proved the mirror functionality with a surface front error less than the required wavelength of 1550 nm. The work evidenced that polishing and the assembly configurations must be selected with particular care; otherwise, the final outcome is compromised for this SLMed component.

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A Novel Lidar Ceilometer

Cited by 8 publications

References 26 publications

Observed and modelled cloud cover up to 6 km height at Station Nord in the high Arctic

Observed and modelled cloud cover up to 6 km height at Station Nord in the high Arctic

A Turbulence-Oriented Approach to Retrieve Various Atmospheric Parameters Using Advanced Lidar Data Processing Techniques

Design and fabrication by selective laser melting of a LIDAR reflective unit using metal matrix composite material

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