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994 Секция 5
The model of short-term hydrodynamic-statistical forecast of heavy summer precipitation over the territories of Ural and West and Middle Siberia, their operative technology
E. V. Perekhodtseva
Russia technological university of electronics and automatics Hydrometeorological center of Russia Email: perekhod@mecom.ru DOI: 10.24411/9999-017A-2020-10158
The hydrodynamic-statistical forecast model have based on the using of output prognostic fields of the region hydrodynamic short-term forecast model at the statistical model of the recognition of situations, involved summer half-days precipitation with the quantity Q > 15 mm/12 h. The rules of the recognition of these events and of the dangerous events with the quantity Q > 40 mm/12 h were calculated on the objective analysis data.
The values of discriminant functions Ft(X) and F2(X) and probabilities Px(X) and P2(X), dependent from discriminant functions and hydrodynamic prognostic values of meteorological elements are calculate in the nodes of the greed for the territories of Ural and Siberia at the operative base. The thresholds of the probabilities are given for the extract of the prognostic area for these events corresponding. The forecast technology schema was developed three years ago. Nowadays the maps of the prognostic areas are submitted on the site of HMS two times a day.
The independent verification of this hydrodynamic-statistical forecast of the half-day precipitation with Q > 15 mm/h throughout the all stations on these territories were realized during two years 2017-2018. The successes of our automatic hydrodynamic-statistical forecast was better than the successes of hydrodynamic forecasts of the different models including the mesoscale model of Hydrometcenter of Russia. The warning-scale of heavy precipitation of these hydrodynamic models forecast with the earliness 12-24 h is less than 30 %. (our value more than 60-75 %). The value of Pirsy - Obuchov criterion of our forecast is also higher than this value for the forecasts of different models. We are going to submit many examples of hydrodynamic-statistical forecast of heavy and dangerous precipitation including the forecast of these events to the date of 25.06. 2019 at Irkutsk area and other. We will also submit the assessments of independent verification made by operative synoptic at corresponding Meteorological Departments.
News solutions of stationary quasi 2D turbulence with global reaction
V. E. Petrov
Kutateladze institute of thermophysics SB RAS
Email: petrov@itp.nsc.ru
DOI: 10.24411/9999-017A-2020-10159
The news numerical and experimental studies led to the partial revision of conceptions about the physical mechanism of the inverse energy cascade in quasi 2D turbulence [1-2]. Two models for quasi 2D turbulence with global reaction are used: 1 model of decaying turbulence [3]; 2 model of forced turbulence [4]. The paper presents the results of the second model with random external force assuming that random external force is a) small-scale, b) short correlated in time and c) statistically homogeneous in space [5-8]. New element introduced in the paper is random external force that allows obtaining solution corresponding to statistically stationary turbulence with global reaction. The model of inverse cascade with the large-scale dissipation mechanism (modification of Kraichnan - Leith - Batchelor model [9]) is used. The properties of turbulence driven by random external force in the modificated Kraichnan - Leith - Batchelor model with global reaction are investigated. It is assumed that turbulence is weak as compared to the mean flow and the Navier - Stokes equation is linearized.
References
1. Chen S , Ecke R E., Eynk G. L., Rivera M., Wan M. and Xiao Z. Physical mechanism of the inverse energy cascade of two-dimensional turbulence // Physical review letters. 2006. V 96. P. (084502-1)-(84502-4).
2. Xiao Z., Wan M., Chen S., Eynk G. L. Physical mechanism of the inverse energy cascade of two-dimensional turbulence: a numerical investigation // J. Fluid Mech. 2009. V. 619. P. 1-44.
3. Jaberi F. A., James S. Effects of Chemical Reaction on Two-Dimensional Turbulence // J. of Scientific Computing. 1999. V. 14, N. 1. P. 31-71.
