Variation Of Pacific-Japan Teleconnection Pattern And Its Relationship With SSTA Over The Tropical Pacific

Based on ERA-40,NCEP/NCAR reanalysis dataset,Hadley SST,the precipitation dataset from753stations in China and the CMIP5dataset, we analysis the interdecadal and interannual variation characteristics of the summer Pacific-Japan (P-J) teleconnection and their causes. Our results are summatized as follows:1. On the interdecadal scale, results indicate that the summer P-J teleconnection pattern has experienced a marked interdacadal variation around the late1970s, with its major teleconnection centers shifting southwestwards. This study also shows that the P-J pattern interdacadal variation is closely related to interdecadal variations in sea surface temperature (SST) over the tropical Pacific and Indian Oceans. Prior to the late1970s, no high correlation coefficients are found between the summer P-J teleconnection pattern and its previous winter SST. However, after that, the P-J teleconnection pattern is found to be highly correlated to the SST over the tropical Pacific and Indian Oceans both in previous winter and spring. This interdecadal change in relationship between P-J teleconnection pattern and SSTs over the tropical Pacific and Indian Ocean is probably due to the fact that the SST interannual variability over the tropical central and eastern Pacific has remarkably increased since the late1970s.2. On the interannual scale, results indicate that the location of the summer P-J teleconnection pattern changes during differert ENSO events. The major teleconnection centers of P-J shift southwestwards (northeastwards) during the summer following El Nino (La Nina). It is also showed that this teleconnection can exist without ENSO. In nature, however, ENSO can modulate this teleconnection, giving rise to the temporal persistence and spatial coherence of northwest Pacific (NWP) climate anonalies.3. Most CMIP5models can well simulate the P-J teleconnection pattern and its relationship with SSTA over the tropical Pacific, i.e., the major teleconnection centers of P-J shift southwestwards (northeastwards) during the summer following El Niflo (La Nina).4. P-J teleconnection pattern has a high correlation with precipitation over the middle and lower reaches of Yangtze River region. It is found that there is a good relationship between the three types of summer rain-band in China and the teleconnection pattern. High (low) P-J index years correspond the3rd (1st) type of rain-band, normal index years correspond the2nd type of rain-band. Studies also point out that there exist obvious interdecadal variation between the rain-band distribution and the P-J teleconnection index.