Discrete dynamic-stochastic model of long-term river runoff variations

2011 ◽  
Vol 38 (5) ◽  
pp. 583-592 ◽  
Author(s):  
A. V. Frolov
Keyword(s):  
Stochastic Model ◽  
River Runoff ◽  
Discrete Dynamic ◽  
Dynamic Stochastic

scholarly journals Comparative Evaluation of Algorithms for Spatial Interpolation of Atmospheric State Parameters Based on a Dynamic Stochastic Model Taking into Account the Vertical Variation of a Meteorological Field

Symmetry ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1207
Author(s):  
Popov ◽  
Lavrinenko ◽  
Krasnenko ◽  
Popova ◽  
Popova ◽  
...  
Keyword(s):  
Stochastic Model ◽  
Spatial Interpolation ◽  
Forecast Model ◽  
Wind Fields ◽  
Vertical Variation ◽  
Meteorological Field ◽  
Dynamic Stochastic ◽  
Atmospheric State ◽  
Observation Space

The paper presents a comparative analysis of two algorithms for the spatial interpolation of meteorological fields. Both algorithms are based on a four-dimensional low-order parametric dynamic stochastic model, taking into account the vertical variation of a meteorological field. The algorithms are characterized by different representations of the forecast model in state and observation space equations for the Kalman filter. The authors studied the accuracy of the spatial interpolation of temperature and wind fields for the developed algorithms. The results of the study are presented in this paper. Numerical simulation was conducted using long-term upper-air observations obtained for a typical mesometeorological range. The results of the study demonstrate that the accuracy of interpolation for the two considered algorithms is comparable.

scholarly journals A Stochastic Model for Virus Growth in a Cell Population

2014 ◽  
Vol 51 (3) ◽  
pp. 599-612 ◽  
Author(s):  
J. E. Björnberg ◽  
T. Britton ◽  
E. I. Broman ◽  
E. Natan
Keyword(s):  
Stochastic Model ◽  
Host Cell ◽  
Cell Population ◽  
Branching Process ◽  
Virus Population ◽  
Virus Growth ◽  
Optimal Balance ◽  
Large Numbers ◽  
A Cell

In this work we introduce a stochastic model for the spread of a virus in a cell population where the virus has two ways of spreading: either by allowing its host cell to live and duplicate, or by multiplying in large numbers within the host cell, causing the host cell to burst and thereby let the virus enter new uninfected cells. The model is a kind of interacting Markov branching process. We focus in particular on the probability that the virus population survives and how this depends on a certain parameter λ which quantifies the ‘aggressiveness’ of the virus. Our main goal is to determine the optimal balance between aggressive growth and long-term success. Our analysis shows that the optimal strategy of the virus (in terms of survival) is obtained when the virus has no effect on the host cell's life cycle, corresponding to λ = 0. This is in agreement with experimental data about real viruses.

ESTIMATION OF LONG-TERM CHANGES IN QUALITATIVE CHARACTERISTICS OF THE OKA RIVER RUNOFF

2021 ◽  
pp. 98-104
Author(s):  
G. KH. ISMAIYLOV ◽  
◽  
N. V. MURASCHENKOVA ◽  
I. G. ISMAIYLOVA
Keyword(s):  
River Runoff ◽  
Maximum Concentration ◽  
Temporal Dynamics ◽  
Ammonium Nitrogen ◽  
Oil Products ◽  
Copper Compounds ◽  
Long Term Changes ◽  
The City ◽  
Qualitative Characteristics

The results of the analysis and assessment of long-term changes in the qualitative characteristics of the Oka River runoff are presented. To analyze the temporal dynamics of the variability of the average annual and maximum concentrations of pollutants in the runoff of the Oka River, we used long-term observational data on typical pollutants for the period 1984-2019. The assessment of the state of the quality of surface waters of the Oka River was carried out according to the values of the concentrations of pollutants in the upper, middle and lower reaches of the river. The dynamics of the main pollutants of the following indicators is considered: ammonium nitrogen, oil products, copper and zinc compounds and easily oxidized organic substances. It was found that in the upper reaches of the river (according to observations of the Oka – Orel city) the main pollutants are ammonium nitrogen and copper compounds, the average annual concentrations of which respectively increased to 9 values. A similar situation was observed downstream of the river (the Oka River – Kaluga city). As a result of the analysis, it was revealed that more noticeable changes in the concentration of pollutants are observed in the section of the river from the city of Murom to the city of Dzerzhinsk. Near the city of Murom, the content of oil products in the water sharply increases. From the beginning of the study period (1984) and until 1995, the average annual concentration varied from 5 to 30 values, and the maximum concentration in the year in creased to 87 values. After 2000, the content of oil products in water dropped sharply and the average annual value did not exceed 3 values, and the maximum concentration was 4-6 values. The paper analyzes the frequency of cases of exceeding the maximum permissible concentrations of pollutants in the Oka River in the mouth of the river. There was a high repeatability of the content of copper compounds in water, which varied from 70 to 88%. The frequency of cases of excess of easily oxidized organic matter in the mouth of the Oka River varied from 64 to 74%. Relatively low, although stable, the repeatability of the content of oil products in water remained, which ranged from 23 to 42%.

The «rainfall-runoff» system and its long-term fluctuations in the Siverskyi Donets River Basin (Ukraine)

2021 ◽  
Author(s):  
Hanna Bolbot ◽  
Vasyl Grebin
Keyword(s):  
Climate Change ◽  
Water Resources ◽  
River Basin ◽  
Air Temperature ◽  
River Runoff ◽  
Annual Runoff ◽  
Annual Precipitation ◽  
Spring Flood ◽  
Current Period

<p>The current patterns estimation of the water regime under climate change is one of the most urgent tasks in Ukraine and the world. Such changes are determined by fluctuations in the main climatic characteristics - precipitation and air temperature, which are defined the value of evaporation. These parameters influence on the annual runoff distribution and long-term runoff fluctuations. In particular, the annual precipitation redistribution is reflected in the corresponding changes in the river runoff.<br>The assessment of the current state and nature of changes in precipitation and river runoff of the Siverskyi Donets River Basin was made by comparing the current period (1991-2018) with the period of the climatological normal (1961-1990).<br>In general, for this area, it was defined the close relationship between the amount of precipitation and the annual runoff. Against the background of insignificant (about 1%) increase of annual precipitation in recent decades, it was revealed their redistribution by seasons and separate months. There is a decrease in precipitation in the cold period (November-February). This causes (along with other factors) a decrease in the amount of snow and, accordingly, the spring flood runoff. There are frequent cases of unexpressed spring floods of the Siverskyi Donets River Basin. The runoff during March-April (the period of spring flood within the Ukrainian part of the basin) decreased by almost a third.<br>The increase of precipitation during May-June causes a corresponding (insignificant) increase in runoff in these months. The shift of the maximum monthly amount of precipitation from May (for the period 1961-1990) to June (in the current period) is observed.<br>There is a certain threat to water supply in the region due to the shift in the minimum monthly amount of precipitation in the warm period from October to August. Compared with October, there is a higher air temperature and, accordingly, higher evaporation in August, which reduces the runoff. Such a situation is solved by rational water resources management of the basin. The possibility of replenishing water resources in the basin through the transfer runoff from the Dnieper (Dnieper-Siverskyi Donets channel) and the annual runoff redistribution in the reservoir system causes some increase in the river runoff of summer months in recent decades. This is also contributed by the activities of the river basin management structures, which control the maintenance water users' of minimum ecological flow downstream the water intakes and hydraulic structures in the rivers of the basin.<br>Therefore, in the period of current climate change, the annual runoff distribution of the Siverskyi Donets River Basin has undergone significant changes, which is related to the annual precipitation redistribution and anthropogenic load on the basin.</p>

A stability analysis on a smoking model with stochastic perturbation

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Anwar Zeb ◽  
Sunil Kumar ◽  
Almaz Tesfay ◽  
Anil Kumar
Keyword(s):  
Stochastic Model ◽  
Stochastic System ◽  
Existence And Uniqueness ◽  
Deterministic Model ◽  
Sufficient Conditions ◽  
Reproductive Number ◽  
Content Type ◽  
Model Form ◽  
The World ◽  
Dynamic Stochastic

Purpose The purpose of this paper is to investigate the effects of irregular unsettling on the smoking model in form of the stochastic model as in the deterministic model these effects are neglected for simplicity. Design/methodology/approach In this research, the authors investigate a stochastic smoking system in which the contact rate is perturbed by Lévy noise to control the trend of smoking. First, present the formulation of the stochastic model and study the dynamics of the deterministic model. Then the global positive solution of the stochastic system is discussed. Further, extinction and the persistence of the proposed system are presented on the base of the reproductive number. Findings The authors discuss the dynamics of the deterministic smoking model form and further present the existence and uniqueness of non-negative global solutions for the stochastic system. Some previous study’s mentioned in the Introduction can be improved with the help of obtaining results, graphically present in this manuscript. In this regard, the authors present the sufficient conditions for the extinction of smoking for reproductive number is less than 1. Research limitations/implications In this work, the authors investigated the dynamic stochastic smoking model with non-Gaussian noise. The authors discussed the dynamics of the deterministic smoking model form and further showed for the stochastic system the existence and uniqueness of the non-negative global solution. Some previous study’s mentioned in the Introduction can be improved with the help of obtained results, clearly shown graphically in this manuscript. In this regard, the authors presented the sufficient conditions for the extinction of smoking, if <1, which can help in the control of smoking. Motivated from this research soon, the authors will extent the results to propose new mathematical models for the smoking epidemic in the form of fractional stochastic modeling. Especially, will investigate the effective strategies for control smoking throughout the world. Originality/value This study is helpful in the control of smoking throughout the world.

Modelling Monetary Policy

2021 ◽  
pp. 293-316
Author(s):  
Juan Antonio Morales ◽  
Paul Reding
Keyword(s):  
Monetary Policy ◽  
Policy Analysis ◽  
Policy Decision ◽  
Central Banks ◽  
Dynamic Stochastic General Equilibrium ◽  
Dsge Models ◽  
Dynamic Stochastic ◽  
Policy Decision Making

This last chapter deals with the toolbox that central banks use to design and implement their monetary policy strategy. Central banks develop various types of model, both for forecasting and for policy analysis. The chapter discusses the main characteristics of the models used, their strengths and limitations. It assesses how dynamic stochastic general equilibrium (DSGE) models are used for monetary policy analysis. Examples are provided on how they contribute to explore fundamental, long-term policy issues specific to LFDCs. The chapter also discusses the contribution of small semi-structural models which, though less strongly theory grounded than DSGE models, can be brought closer to the available data and are therefore possibly better suited to the context of LFDCs. Attention is also drawn to the key role of judgement as the indispensable complement, in monetary policy decision-making, to model-based policy analysis.

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