Ratios of record high to record low temperatures in Europe exhibit sharp increases since 2000 despite a slowdown in the rise of mean temperatures

Abstract

A study has been undertaken to analyze the behavior of record high and low values of temperature since the early 1950s for 30 locations spread across Europe. When establishing the ratios of the number of record Tmax to record Tmin values in each year, it is seen that there is a sharp increase in these ratios in the most recent decade. This seems to be an apparent paradox in view of the slow-down in atmospheric temperatures that has been observed since the early 2000s at both the hemispheric and European scales, but closer analysis suggests that the relationship between the record high:low ratios and mean annual temperatures is not linear but rather a square relationship. It is suggested that the record high to record low ratios in both the Mediterranean region and beyond 60° latitude north, observed in the most recent decade, may be related to an amplification of low-level atmospheric temperatures resulting from shorter snow seasons in the north and enhanced summer dryness in the south.