174th meeting of the seminar
«Mathematical modeling of geophysical processes: direct and inverse problems»
The seminar is devoted to the consideration of various aspects of mathematical modeling of physical processes in the atmosphere, hydrosphere and active layer of land, associated with solving problems arising in the study of the problems of climate change and the natural environment.
Seminar Organizing Committee
| Leaders: |
Doctor of Physics and Mathematics A.V. Glazunov (Marchuk Institute of Numerical Mathematics of RAS) Doctor of Physics and Mathematics I.A. Repina (A.M. Obukhov Institute of Atmospheric Physics of RA) Doctor of Physics and Mathematics V.M. Stepanenko (RCC MSU, Geographical Faculty of Moscow State University) |
| Secretary: |
Yu.I. Yarynich (RCC MSU, A.M. Obukhov Institute of Atmospheric Physics of RAS). |
PROGRAM
17:15
| Е.A. Malinovskaya | IAP RAS |
| O.G. Chhetiani | IAP RAS |
| G.V. Azizyan | IAP RAS |
Turbulence in convective near-surface air layer.
In natural conditions of daily heating of the surface of arid and subarid territories, horizontal and vertical temperature gradients occur. The inhomogeneity of the temperature field affects convective movements, air rise with the removal of submicron aerosol. The density distribution of convective elements is associated with temperature pulsations, which affects the variation of dust aerosol concentration with altitude. Triangular sawtooth-shaped bursts, called “ramps”, are found in both temperature and velocity measurement data, defining the convective heat flux structure.
In complex expeditionary studies of the A.M. Obukhov IFA RAS conducted in the Chernozemelsky district of the Republic of Kalmykia, temperature and velocity pulsations at a height of up to 1 m from the surface were determined. The fixing frequency of 1000 Hz allowed us to identify, based on the analysis of spectral functions, characteristic scales of structures from 0.2 to 2 m and from 0.02 to 0.1 m for the upper and lower vicinities of kinks near the inertial interval “-5/3”. At frequencies above the inertial interval, degrees close to “-1” are determined, which are characteristic of the hot time of day after surface warming. The degree “-1” is associated with the presence of thermal inhomogeneities and a significant temperature gradient. The degree “-4/3” is caused by the condition of preservation of thermal inhomogeneities generating turbulent pulsations.
Visual analysis of the relative changes in the pulsation components of temperature reveals the presence of triangular asymmetric structures (“ramps”). Their size depends on the averaging interval and varies from 300 ms to 10 s; the comparison reveals cases of self-similarity of the structures.
The authors thank L.O. Maksimenkov, E.A. Shishov, B.A. Khartskhaev (Kalmykia) for their help in organizing and carrying out field measurements. We express our gratitude to G.S. Golitsyn and E.B. Gledzer for attention to the work and constructive comments.
Funding source: the research was supported by the Russian Science Foundation (project 25-17-00346)
The seminar also will be held in the form of a webinar on the Zoom platform.
Topic: семинар "Математическое моделирование геофизических процессов: прямые и обратные задачи".
Time: Apr 17, 2025 05:15 PM Moscow (GMT+3)
Meeting ID: 863 4629 0196
Passcode: 242832
Video recordings of the seminar are available on our youtube channel.
For communication on all issues related to the work of the seminar, please contact the academic secretary Yuliya Yarynich at julia.yarinich@srcc.msu.ru