Tropospheric Response to Stratospheric Variability via Lagged Quantile Regression

Stratospheric variability may affect tropospheric weather on time scales between a few weeks and months, thus providing great potential for sub-seasonal to seasonal forecasts of extremes. Unlike standard linear regression, which is based the conditional mean response variable, lagged quantile regression used here, enables modeling variable's complete distribution. Using ERA5 reanalysis, we explore relation prominent teleconnection indices gridded fields stratosphere during boreal winter various quantiles lags. Significant differences in duration, strength, direction stratosphere-troposphere connection outer compared median are identified. In particular, extremes their polar vortex strength discussed, an outlook given.