LONG-TERM CHANGES IN THE TEMPERATURE AND PRECIPITATION REGIME IN ST. PETERSBURG FROM EMPIRICAL DATA AND MODEL ESTIMATES OF REGIONAL CHANGES IN THE PAST AND FUTURE

G. S. Golitsyn, L. K. Efimova, I. I. Mokhov, V. A. Tikhonov, and V. Ch. Khon

Quantitative estimates of statistically significant temperature and precipitation trends in St. Petersburg including those for annual mean regimes and for different months are derived from observational data of the 18th—20th centuries. The most considerable temperature and precipitation increase has been found for the cold season. In addition to changes in average characteristics of temperature and precipitation, changes in characteristics of their interannual variability have also been found. In particular, the variance of summer and winter precipitation in St. Petersburg increased in the second half of the 20th century compared to the second half of the 19th century and the first half of the 20th century. Estimates of surface air temperature and precipitation variations in St. Petersburg in the 19th—21st centuries are obtained using numerical calculations with coupled atmosphere—ocean general circulation models when greenhouse gases increase in the atmosphere.