SINE APPROXIMATION OF THE ANNUAL COURSE OF DAILY MEAN AIR TEMPERATURE IN RUSSIA IN THE TWENTIETH CENTURY

S. M. Semenov and E. S. Gelver

In this paper, annual course of daily mean temperature is characterized for a given time period by three parameters, namely, T0, A, and t0, defining zero and first order terms of its Fourier series on the time interval of one calendar year, respectively. Here T0 is a long time average value, A is an amplitude of the sine function, and t0 is a day of a calendar year at which daily mean temperature reaches its maximum value. These three parameters have been estimated from daily observational data at each meteorological station of international exchange located within the ex USSR territory. The estimates were obtained for two time periods, namely, for 1936–1965 and 1966–1995. The schematic maps of changes of these parameters during 30 years have been drawn for the territory of Russia.