A study on the asymmetric information transfer between tropical central-eastern Pacific and low-latitude atmosphere during ENSO

In this article, information transfer over the tropical eastern Pacific is discussed in different ENSO phases based on Transfer Entropy (TE). Information transferred from ocean to the atmosphere is the main feature in both El Niño and La Nia phases and also in neutral phase. Compared to that in neutral phase, the intensity of information transfer is stronger in both El Niño and La Nia phases, while it is slightly stronger in La Nia phase than in El Niño phase. Using rearrangement of slide random samples (RSRS), the relationship between sea surface temperature anomalies (SSTA) over the tropical eastern Pacific and the intensity of information transfer is analyzed with a focus on the asymmetry of information transfer. Three stages are identified from the relationship: Liked La Nia, liked Neutral, and liked El Niño. As the negative SST anomalies weaken, information transfer weakens in the liked La Nia stage; as the negative SST anomalies gradually change to positive anomalies, information transfer does not exist significant changing trends in liked Neutral stage; as the positive SST anomalies intensify, information transfer enhances in liked El Niño stage. The asymmetry exists in the air-sea interaction. When information transferred from ocean to the atmosphere is stronger, information transferred from atmosphere to ocean is stronger, too.