Please use this identifier to cite or link to this item: https://oa.tib.eu/renate/handle/123456789/802
Files in This Item:
File SizeFormat 
amt-6-1041-2013.pdf1,94 MBAdobe PDFView/Open
Title: Application of linear polarized light for the discrimination of frozen and liquid droplets in ice nucleation experiments
Authors: Clauss, T.Kiselev, A.Hartmann, S.Augustin, S.Pfeifer, S.Niedermeier, D.Wex, H.Stratmann, F.
Publishers version: https://doi.org/10.5194/amt-6-1041-2013
URI: https://doi.org/10.34657/803
https://oa.tib.eu/renate/handle/123456789/802
Issue Date: 2013
Published in: Atmospheric Measurement Techniques, Volume 6, Issue 4, Page 1041-1052
Publisher: München : European Geopyhsical Union
Abstract: We report on the development and test results of the new optical particle counter TOPS-Ice (Thermo-stabilized Optical Particle Spectrometer for the detection of Ice). The instrument uses measurements of the cross-polarized scattered light by single particles into the near-forward direction (42.5° ± 12.7°) to distinguish between spherical and non-spherical particles. This approach allows the differentiation between liquid water droplets (spherical) and ice particles (non-spherical) having similar volume-equivalent sizes and therefore can be used to determine the fraction of frozen droplets in a typical immersion freezing experiment. We show that the numerical simulation of the light scattered on non-spherical particles (spheroids in random orientation) considering the actual scattering geometry used in the instrument supports the validity of the approach, even though the cross-polarized component of the light scattered by spherical droplets does not vanish in this scattering angle. For the separation of the ice particle mode from the liquid droplet mode, we use the width of the pulse detected in the depolarization channel instead of the pulse height. Exploiting the intrinsic relationship between pulse height and pulse width for Gaussian pulses allows us to calculate the fraction of frozen droplets even if the liquid droplet mode dominates the particle ensemble. We present test results obtained with TOPS-Ice in the immersion freezing experiments at the laminar diffusion chamber LACIS (Leipzig Aerosol Cloud Interaction Simulator) and demonstrate the excellent agreement with the data obtained in similar experiments with a different optical instrument. Finally, the advantages of using the cross-polarized light measurements for the differentiation of liquid and frozen droplets in the realistic immersion freezing experiments are discussed.
Keywords: data set; discriminant analysis; droplet; experimental study; freezing; instrumentation; light effect; light scattering; linearity; nucleation; polarization
Type: article; Text
Publishing status: publishedVersion
DDC: 550
License: CC BY 3.0 Unported
Link to license: https://creativecommons.org/licenses/by/3.0/
Appears in Collections:Geowissenschaften

Show full item record
Clauss, T., A. Kiselev, S. Hartmann, S. Augustin, S. Pfeifer, D. Niedermeier, H. Wex and F. Stratmann, 2013. Application of linear polarized light for the discrimination of frozen and liquid droplets in ice nucleation experiments. 2013. München : European Geopyhsical Union
Clauss, T., Kiselev, A., Hartmann, S., Augustin, S., Pfeifer, S., Niedermeier, D., Wex, H. and Stratmann, F. (2013) “Application of linear polarized light for the discrimination of frozen and liquid droplets in ice nucleation experiments.” München : European Geopyhsical Union. doi: https://doi.org/10.5194/amt-6-1041-2013.
Clauss T, Kiselev A, Hartmann S, Augustin S, Pfeifer S, Niedermeier D, Wex H, Stratmann F. Application of linear polarized light for the discrimination of frozen and liquid droplets in ice nucleation experiments. München : European Geopyhsical Union; 2013.
Clauss, T., Kiselev, A., Hartmann, S., Augustin, S., Pfeifer, S., Niedermeier, D., Wex, H., & Stratmann, F. (2013). Application of linear polarized light for the discrimination of frozen and liquid droplets in ice nucleation experiments (Version publishedVersion). Version publishedVersion. München : European Geopyhsical Union. https://doi.org/https://doi.org/10.5194/amt-6-1041-2013
Clauss T, Kiselev A, Hartmann S, Augustin S, Pfeifer S, Niedermeier D, Wex H, Stratmann F. Application of linear polarized light for the discrimination of frozen and liquid droplets in ice nucleation experiments. Published online 2013. doi:https://doi.org/10.5194/amt-6-1041-2013


This item is licensed under a Creative Commons License Creative Commons