Regional features of intraseasonal temperature variability in the regions of Northern Eurasia with global climate change

Abstract

Abstract Polymodal (bimodal) features of the probability density functions (PDFs) for long term series of surface air temperature anomalies in transitional (fall, spring) seasons are studied based on daily data from meteorological observations in various North Eurasian regions using a stochastic energy balance model. The observed PDFs are characterized by bimodality with the minimums laying near 0° C. Changes of weather regimes since the middle of 20th century until recent years are analyzed. The increase in probability of negative temperatures for both transitional seasons in the 21st century compared to the 20th century can be linked to global changes in atmosphere circulation patterns and, particularly, to intensification of cold air outbreaks occurrence in spring seasons. “Indian summer” (the effect of recurrent warming in fall seasons) phenomenon is stronger in the 20th century PDF, while the bimodality of PDF around 0° C can signify the nonlinear dependence of albedo on SAT.