Analysis of Bifurcation Points Position in Time Series of Meteorological Values in the South of Russia

The work aims to determine the moment in time (bifurcation points) when the parameters of temporal trends (both in sign and in speed) change. These parameters describe changes in average annual temperatures and annual precipitation amounts. A linear mathematical model is used to determine the indicated points in time; with the help of such model, each time series of average annual temperatures or annual precipitation amounts (obtained at 11 meteorological stations for 1960–2020) is replaced by one or more segments, and the joining points of these segments indicate the moments when the parameters of the time trend change. The research revealed that if the general trend in the average annual temperature change is increase, the approach used revealed the moments when the dynamics changed both in sign and in speed. For instance, according to the data of Sochi meteorological station, there was a drop in the mean annual temperatures in 1960–1993, and a steady increase in 1994–2020. The nature of the temporal variability of annual precipitation amounts turned out to be more complex. Calculating the position of bifurcation points allows determining the onset of climatic changes in a particular region, and the updated values of the time trend parameters allow accessing the trend of changes in average annual temperatures and annual precipitation amounts in the short term.