ECCE Seminar - Impact of ENSO and trends on the distribution of North American wintertime daily temperature

Please use this Zoom link (Meeting ID: 652 577 1125, Password: Tippett) for online attendance.

Impact of ENSO and trends on the distribution of North American wintertime daily temperature

The effect of the El Niño/Southern Oscillation (ENSO) teleconnection and climate change trends on observed North American wintertime daily 2-m temperature is investigated for 1960–2022 with a quantile regression model, which represents the variability of the full distribution of daily temperature, including extremes and changes in spread. Climate change trends are included as a predictor in the regression model to avoid the potentially confounding effect on ENSO teleconnections. The ENSO response is taken to be piecewise linear with separate predictors for warm and cool ENSO conditions. The relationship between these predictors and shifts in median, interquartile range, skewness, and kurtosis of daily 2-m temperature are summarized through Legendre polynomials. Warm ENSO conditions result in significant warming shifts in the median and contraction of the interquartile range in central-northern North America, while no opposite effect is found for cool ENSO conditions in this region. In the southern U.S., cool ENSO conditions produce a warming shift in the median, while warm ENSO has little impact on the median, but contracts the interquartile range. Climate change trends are present as a near-uniform warming in the median and across quantiles and have no discernible impact on interquartile range or higher-order moments.