Statistical Aspects of Quantitative Estimation of Polar Amplification. Part 1: The Ratio of Trends.

Statistical aspects of the quantitative estimation of the climate change polar amplification (PA) are considered. A theoretical study is provided of the distribution density for the PA sample coefficient defined as the ratio of the linear trend coefficients of spatially averaged surface air temperature. It is shown that heavy tails of the distribution lead to instability of the PA sample estimates. A statistically valid quantification of the PA can be obtained from the results of the ensemble modeling of climate change based on the Fieller's method. The applicability of the method in the case of a non-stationary climate system response to external forcing is considered. [ABSTRACT FROM AUTHOR]