Statistical estimation of the ergodicity of the series of the average monthly runoff of the Desna River and its correlation characteristics
S. O. Moskalenko, Liudmyla Malytska · 15th International Conference Monitoring of Geological Processes and Ecological Condition of the Environment · 2021
Summary The work’s aim is to study the average monthly water discharge of the Desna River as an ergodic periodically correlated random process. Due that, the methods of the theory of random functions are applied. The assessment of the statistical characteristics (periodic functions of mathematical expectation, dispersion and correlation functions) was carried out according to the data of hydrological observations on the Desna River (Chernigov) for 1920–2015. The formed time series with a discreteness step of one month consists of 1152 indicators of average monthly water flow rates. According to estimates of mathematical expectation and dispersion with a correlation period of twelve months, we obtained a model of ergodic random process. According to the correlation matrix of the average monthly water discharge, the ordinates of the function for each month of the year are obtained. It is concluded that in the water regime of the Desna River the highest runoff occurs in April-May - the passage of spring floods. For all other months - low water. Water flow variability is highest in March-May. In addition, for April and May, unlike the low-flow months, there is no relationship between the water runoff of these months and the other months of the year.