The Construction of the Linear Discriminant Analysis Function and Its Evaluation to Determine Extreme Meteorological Phenomena (Ice Deposits) in Ukraine

Abstract

o predict the possibility of ice deposits on the territory of Ukraine in the winter season, an analogous approach is proposed using the construction of the equations of the linear discriminant function. For this, the correlation coefficients between 13 meteorological values (per day) at the start dates of ice deposits at all stations of Ukraine were calculated. Significant correlation coefficients were determined between individual meteorological variables, such as average air temperature, maximum, minimum average air humidity, average wind speed, and atmospheric pressure at sea level. It is these quantities that were used to construct the equations of the linear discriminant function and for the dates of the actual formation of ice deposits and the further forecast of its formation from a three-day lead time. As a result of the calculations for the winter season of 2001-2013 an equation of the linear discriminant function was obtained for the dates of the actual formation of ice deposits and a sufficiently high justification was obtained. Also, to predict the possible formation of ice deposits with a three-day lead time, a prognostic function of linear discriminant analysis was obtained to determine possible such deposits for the winter season of 2001-2010. On the example of the regional centers, a satisfactory assessment of the justification on an independent material for the winter season of 2011-2016 was obtained. Thus, in constructing linear discriminant functions to determine the possibility of such an adverse event as ice deposition, a number of conclusions were obtained: – The sufficiently high validity of the discriminant functions of extreme meteorological phenomena (ice deposits) for the winter season 2001-2013 was obtained. It ranges from 91 % (for the data set at selected dates with ice deposits) up to 90% (for an array of data at the date of extreme cold ). – A sufficiently high estimate of the validity of the independent material for the winter season 2014-2016 was obtained. It is up to 78 % (for an array of data on extreme cold dates and from 90 % ( for an array of data on selected dates with ice deposits) . – The prognostic function of linear discriminant analysis was obtained to determine possible (with 3-day timeliness) extreme meteorological phenomena (ice) during the winter season 2001-2010, using only meteorological values with statistically significant correlation, namely, the maximum air temperature; average humidity; and average wind speed. – Sufficiently significant and satisfactory validity of the prognostic functions of possible (with 3-day timeliness) extreme meteorological phenomena (ice deposits) for the winter season 2001-2010 was obtained.