The modulation effect of the Victoria mode on the uncertainty connection between ENSO and winter European surface air temperature

Abstract

While El Niño-Southern Oscillation (ENSO) has widespread impacts on the climate around the Pacific and North America, the relationship between ENSO and winter surface air temperature (SAT) in Europe is less well established. This study investigates the modulation effects of the spring Victoria mode (VM) on the weak ENSO–SAT connection in the following winter based on reanalysis data and numerical experiments. It is shown that the connection between ENSO and the winter SAT in central Europe has a significant and positive (negative) correlation during the positive (negative) VM phase. Further analysis shows that the sea surface temperature (SST) anomalies associated with ENSO play an important role in the VM modulation. For the positive VM phase, ENSO combined with the SST warming mode in the western North Pacific induces the East Atlantic teleconnection pattern, which strengthens the anomalous warm advection and leads to the positive SAT anomalies in central Europe. In contrast, for the negative VM phase, ENSO could trigger a negative North Atlantic Oscillation pattern through intermediate SST anomalies in the tropical North Pacific, favoring the formation of the negative central European SAT anomalies. The remarkable modulation effect of the VM on the connection between ENSO and winter central European SAT is further verified through forced experiments using an atmospheric model. This could provide hope that ENSO can make predictions for the winter SAT in central Europe, considering the phase of the preceding spring VM.