Impact of Global Warming on Zero Degree Isotherm of Near Surface Temperature

Abstract

The evaluation of the modern global warming impact on the zero degree isotherm crossing dates of near-surface temperature is unequivocally determined by the length of the warm (cold) season in a given region. The study was conducted using perennial, near-surface temperature field data from ten observation points in a complex, highland region. The correlation changes of the dates of the crossing of the zero degree isotherm of temperature concerning the vertical and horizontal displacement is studied. The statistical structure of the multi-year change in the dates is established. It is accepted that the increase in the warm season caused by global warming mainly occurs in the first half of the year when the zero-degree isotherm crosses from negative to positive. There are also rare cases when the warm season, for a long time, experiences a decrease in the opposite.