学术讲座公告-基于次声探测的对流层中间层低热层风场研究

  • 发布时间:[2017-05-12] 来源:[学院] 点击量:[4311]

报告时间:2017年5月18日(周四)上午9:00
报告地点:学院320会议室

报告题目:
Study of the wind velocity layered structure in the stratosphere, mesosphere and lower thermosphere by using infrasound probing of the atmosphere

报告人:
Prof. Igor Chunchuzov

报告主题简介:
The wind velocity structure in the upper stratosphere, mesosphere and lower thermosphere (MLT) is studied with the recently developed method of infrasound probing of the atmosphere. The method is based on the effect of infrasound scattering from highly anisotropic wind velocity and temperature inhomogeneities in the middle and upper atmosphere. The scattered infrasound field propagates in the acoustic shadow zones, where it is detected by microbarometers. The vertical profiles of the wind velocity fluctuations in the upper stratosphere (30-52 km) and MLT (90- 140 km) are retrieved from the wave forms and travel times of the infrasound signals generated by explosive sources such as volcanoes and surface explosions. The fine-scale wind layered structure in these layers was poorly observed until present time by other remote sensing methods, including radars and satellites.  It is found that the MLT atmospheric layer (90-102 km) can contain extremely high vertical gradients of the wind velocity, up to 10 m/s per 100 m. The effect of a fine-scale wind velocity structure on the wave forms of infrasound signals is studied. The vertical wavenumber spectra of the retrieved wind velocity fluctuations are obtained for the upper stratosphere. Despite the difference in the locations of the explosive sources all the obtained spectra show the existence of high vertical wavenumber spectral tail with a -3 power law decay. The obtained spectral characteristics of the wind fluctuations are necessary for improvement of gravity wave drag parametrizations for numerical weather forecast.

报告人简介:
Dr. Igor Chunchuzov received the PhD degree and degree of Doctor of Physical and Mathematical Sciences from Lomonosov Moscow State University in 1980 and 1992, respectively. In 1985 he received a gold medal of Russian Academy of Sciences for the best scientific work among young scientists. Since 1992 he is a Leading Researcher at the Obukhov Institute of Atmospheric Physics in Moscow. His main research areas are atmospheric and oceanic acoustics, internal gravity wave dynamics and mesoscale turbulence, nonlinear acoustics, remote sensing of the atmosphere. In 1994 he was a Visiting Professor at Physical Department of Bergen University in Norway, where he developed a 3-D model of internal gravity wave spectrum in the atmosphere. In 1996-2001 he was working with Canadian Centre for Remote Sensing, Ottawa in Canada as a Visiting Senior Scientist. In March-July of 2010 he was invited to the National Centre of Physical Acoustics (NCPA, University of Mississippi, USA) to develop a model of infrasound propagation through the atmosphere with a fine-scale layered structure. Since 2012 he has a continuous collaboration with the Institute of Acoustics CAS and Institute of Atmospheric Physics CAS in Beijing in various fields of acoustics, atmospheric dynamics and infrasound remote sensing of the atmosphere. He published more than 110 papers. He is a member of Russian and American Acoustical Societies.

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