EGU2020-21073
https://doi.org/10.5194/egusphere-egu2020-21073
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Ground-based measurements of turbulence in electrified clouds

Evgeny Mareev, Vladimir Klimenko, Lev Lubyako, Mariya Shatalina, Svetlana Dementyeva, and Nikolay Ilin
Evgeny Mareev et al.
  • Institute of Applied Physics, Geophysical Research Department, Nizhny Novgorod, Russian Federation (evgeny.mareev@gmail.com)

A problem of the electric field dynamics in turbulent electro-active clouds (Cumulus, Stratus, Cumulonimbus) is one of the most relevant and complex problems of dynamical meteorology and atmospheric electricity. This problem is important for the study of intense large-scale electric field and its fluctuations that may lead to high-energy particle flows and lightning discharges, for electric current parameterization. Direct field measurements in convective clouds with a developed electrical structure are very difficult; so one of urgent tasks is the development of remote sensing methods for turbulence characteristics in electro-active clouds.

The growth of a large-scale electric field in a turbulent atmosphere is caused by the generation of an electric charge on colliding particles (hydrometeors and dust). Meanwhile, observations (including preliminary observations of the authors) and theoretical studies (Mareev and Dementyeva, 2017) show that intensification of thunderstorm activity can be associated with increased turbulence in the cloud. This paper presents new ideas and results of experimental and theoretical studies of the role of turbulence in electro-active clouds.

The main attention is paid to complex remote observations of different types of clouds with an experimental set-up including the microwave radiometers of 3 cm and 8 mm wavelengths (with a time resolution of order of one second), the network of electrostatic fluxmeters spaced by several kilometers each from another, and the meteorological radar. The data of recent several years were used for analysis. Note that recently space-borne passive microwave radiometry of intense convective clouds (see, for example, Peterson et al., 2017) attracted more attention compared to ground-based microwave observations. A principal idea of our approach is to use the wave-length channels allowing us to reveal both optically thick and optically transparent cloud events from the data on fluctuations in the brightness temperature of the atmosphere.

A special attention was paid to comparative analysis of the turbulence characteristics in thunderclouds and in clouds that do not have a developed electrical structure. The spectral characteristics of electric field and brightness fluctuations were found to be associated with atmospheric air turbulence and mostly are quantitatively described by Kolmogorov-type spectra. Compared with ordinary Cumulus and Stratus clouds, a limited band near a frequency of ~ 0.01 Hz with a higher level of fluctuations is distinguished in the spectral density of fluctuations in the brightness temperature of thunderclouds. The spectra of fluctuations of the electric field caused by thunderclouds, as well as turbulence interior thundercloud, are significantly different from the spectra caused by ordinary Cumulus and layered clouds.

The work was supported by the Russian Foundation for Basic Research (projects no. 19-05-00975 and 18-45-520010).

References

Mareev E.A., Dementyeva S.O. (2017), The role of turbulence in thunderstorm, snowstorm, and dust storm electrification. Journal of Geophysical Research: Atmospheres, V. 122, No. 13, P. 6976-6988. doi: 10.1002/2016JD026150.

Peterson M., Liu C., Mach D., Deierling W., Kalb C. (2015), A method of estimating electric fields above electrifi_ed clouds from passive microwave observations. J. Atmos. Ocean. Tech., V.32 (8), P.1429-1446. doi: 10.1175/ JTECH-D-14-00119.1.

How to cite: Mareev, E., Klimenko, V., Lubyako, L., Shatalina, M., Dementyeva, S., and Ilin, N.: Ground-based measurements of turbulence in electrified clouds, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-21073, https://doi.org/10.5194/egusphere-egu2020-21073, 2020

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Presentation version 1 – uploaded on 05 May 2020
  • CC1: Comment on EGU2020-21073, Olaf Scholten, 05 May 2020

    Dear Evgeny,

    The work you discuss is very interesting and I was not aware of this. Using a completely different method we have also investigaded the electric field in clouds, not necessarily thunderclouds, and you can find it (copied as bibtex reference) at

    @article{Trinh:2020,
    author = {Trinh, T. N. G. and Scholten, O. and Buitink, S. and Ebert, U. and Hare, B. M. and Krehbiel, P. R. and Leijnse, H. and Bonardi, A. and Corstanje, A. and Falcke, H. and Huege, T. and H\"{o}randel, J. R. and Krampah, G. K. and Mitra, P. and Mulrey, K. and Nelles, A. and Pandya, H. and Rachen, J. P. and Rossetto, L. and Rutjes, C. and ter Veen, S. and Winchen, T.},
    title = {Determining Electric Fields in Thunderclouds With the Radiotelescope LOFAR},
    journal = {Journal of Geophysical Research: Atmospheres},
    volume = {125},
    number = {8},
    pages = {e2019JD031433},
    doi = {10.1029/2019JD031433},
    url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019JD031433},
    eprint = {https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2019JD031433},
    note = {e2019JD031433 10.1029/2019JD031433},
    abstract = {Abstract An analysis is presented of electric fields in thunderclouds using a recently proposed method based on measuring radio emission from extensive air shower events during thunderstorm conditions. This method can be regarded as a tomography of thunderclouds using cosmic rays as probes. The data cover the period from December 2011 till August 2014. We have developed an improved fitting procedure to be able to analyze the data. Our measurements show evidence for the main negative-charge layer near the -10° isotherm. This we have seen for a winter as well as for a summer cloud where multiple events pass through the same cloud and also the vertical component of the electric field could be reconstructed. On the day of measurement of some cosmic-ray events showing evidence for strong fields, no lightning activity was detected within 100 km distance. For the winter events, the top heights were between 5 and 6 km, while in the summer, typical top heights of 9 km were seen. Large horizontal components in excess of 70 kV/m of the electric fields are observed in the middle and top layers.},
    year = {2020}
    }

    Regards,  Olaf Scholten

     
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    • AC1: Reply to CC1, Evgeny Mareev, 05 May 2020

      Thank you very much, Olaf. I will look at your work and will answer to you in more detail.

      Sincerely Evgeny