Rayleigh scattering

Young, A. T.

doi:10.1364/ao.20.000533

Cited by 194 publications

(103 citation statements)

References 16 publications

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“…The design and integration of the Doppler wind capability was performed in a way that the time series of observations was not interrupted. We have developed a single photon spectrometer analyzing the Doppler shift of the Cabannes line using iodine absorption spectroscopy at line 1109 (Young, 1981;She et al, 2007;Gerstenkorn and Luc, 1978). The Cabannes line and the iodine absorption spectrum are shown in Fig.…”

Section: Methods and Instrumental Setupmentioning

confidence: 99%

Doppler Rayleigh/Mie/Raman lidar for wind and temperature measurements in the middle atmosphere up to 80 km

Baumgarten

2010

Atmos. Meas. Tech.

129

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Abstract.A direct detection Doppler lidar for measuring wind speed in the middle atmosphere up to 80 km with 2 h resolution was implemented in the ALOMAR Rayleigh/Mie/Raman lidar (69 • N, 16 • E). The random error of the line of sight wind is about 0.6 m/s and 10 m/s at 49 km and 80 km, respectively. We use a Doppler Rayleigh Iodine Spectrometer (DoRIS) at the iodine line 1109 (∼532.260 nm). DoRIS uses two branches of intensity cascaded channels to cover the dynamic range from 10 to 100 km altitude. The wind detection system was designed to extend the existing multi-wavelength observations of aerosol and temperature performed at wavelengths of 355 nm, 532 nm and 1064 nm. The lidar uses two lasers with a mean power of 14 W at 532 nm each and two 1.8 m diameter tiltable telescopes. Below about 49 km altitude the accuracy and time resolution is limited by the maximum count rate of the detectors used and not by the number of photons available. We report about the first simultaneous Rayleigh temperature and wind measurements by lidar in the stratoand mesosphere on 17 and 23 January 2009.

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Section: Methods and Instrumental Setupmentioning

confidence: 99%

Doppler Rayleigh/Mie/Raman lidar for wind and temperature measurements in the middle atmosphere up to 80 km

Baumgarten

2010

Atmos. Meas. Tech.

129

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“…Assuming that a model distinguishes atmospheric gases such as nitrogen, oxygen, argon, and water vapor, the molecule scattering calculation can be performed for each individual gas type and molecule size using the Rayleigh theory (Young, 1981).…”

Section: Scattering By Moleculesmentioning

confidence: 99%

A Backscatter Lidar Forward Operator for Particle-Representing Atmospheric Chemistry Models

Geisinger

Behrendt

Wulfmeyer

et al. 2016

Preprint

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Abstract.State-of-the-art atmospheric chemistry models are capable of simulating the transport and evolution of particles and trace gases but there is a lack of reliable methods for model validation and data assimilation. Networks of automated ceilometer lidar systems (ACLs) could be used to fill this gap. These are already used for the detection of clouds and aerosols, providing a 3D dataset of atmospheric backscatter profiles. However, as the aerosol number concentration cannot be obtained from the ACL 5 data alone, one needs a backscatter-lidar forward model to simulate lidar profiles from the model variables. Such an operator allows then for a qualitative and quantitative model validation based on ACL data. In this work, we present a new backscatterlidar operator which contains most of the microphysical properties of aerosol particles, discuss sensitivity studies and compare simulated with measured ACL profiles. A major challenge is the high sensitivity of the optical cross sections to the particle size and shape: A slightly different particle radius may lead to quite a large change of the scattering properties. As most particle 10 size distributions are continuous in reality, the optical cross sections are averaged over certain size-intervals which also reduces the problematic and unrealistic sensitivity significantly. To calculate the attenuated backscatter coefficient, the size-dependent particle number concentration and the scattering properties of each particle type and size have to be simulated. While the particle number concentration is a model output variable, the scattering properties have to be determined by extensive scattering calculations. As these scattering calculations require assumptions about the particle refractive indices and shapes, sensitivity 15 studies were performed to estimate the uncertainties related to the particle properties as represented by the model system.The strong sensitivity of the scattering characteristics to the particle radius was largely reduced by size-averaging algorithms.We focus on a case study of the eruption of the Islandic volcano Eyjafjallajökull from 20 March 2010 to 24 May 2010. The Consortium for Small-scale Modeling -Aerosols and Reactive Trace gases (COSMO-ART) model of DWD (Deutscher Wetterdienst) and KIT (Karlsruhe Institute of Technology) was used during this event for ash-dispersion simulation over Europe. 20For the forward model, the attenuated backscatter coefficient is used as lidar-independent variable, as it only relies on the laser wavelength. Finally, the forward modeled lidar profiles were compared to ACL measurements. Significant differences between ACL profiles and the output of the forward operator applied to the COSMO-ART data were found but also several identical features have been observed. Comparing the data quantitatively revealed that the model-predicted ash number concentration is slightly too high. We identified the following key issues which are mandatory for performing quantitative comparisons be-

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“…The summation over i for β sca includes Rayleigh scattering, and scattering of aerosols and clouds. The Rayleigh scattering consists of the central Cabannes line and rotational Raman scattering (Young, 1981). The absorption coefficient includes absorption by clouds, aerosols and various molecular species.…”

Section: Inclusion Of Rrs In the Libradtran Radiative Transfer Modelmentioning

confidence: 99%

Technical Note: A new discrete ordinate first-order rotational Raman scattering radiative transfer model – implementation and first results

2011

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Abstract. Rotational Raman scattering in the Earth's atmosphere explains the filling-in of Fraunhofer lines in the solar spectrum. A new model including first-order rotational Raman scattering has been developed, based on a reimplementation of the versatile discrete ordinate radiative transfer (DISORT) solver in the C computer language. The solver is fully integrated in the freely available libRadtran radiative transfer package. A detailed description is given of the model including the spectral resolution and a spectral interpolation scheme that considerably speeds up the calculations. The model is used to demonstrate the effect of clouds on top and bottom of the atmosphere filling-in factors and differential optical depths. Cloud effects on vertical profiles of the filling-in factor are also presented. The spectral behaviour of the model is compared against measurements under thunderstorm and aerosol loaded conditions.

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Rayleigh scattering

Cited by 194 publications

References 16 publications

Doppler Rayleigh/Mie/Raman lidar for wind and temperature measurements in the middle atmosphere up to 80 km

Doppler Rayleigh/Mie/Raman lidar for wind and temperature measurements in the middle atmosphere up to 80 km

A Backscatter Lidar Forward Operator for Particle-Representing Atmospheric Chemistry Models

Technical Note: A new discrete ordinate first-order rotational Raman scattering radiative transfer model – implementation and first results

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