Enhanced joint effects of ENSO and IOD on Southeast China winter precipitation after 1980s

Based on the NCEP/NCAR reanalysis data, COBE sea surface temperature (SST) and GPCC precipitation, influences of El Niño-South Oscillation (ENSO) variability winter rainfall anomalies in Southeast China is analyzed under synergistic effect Indian Ocean Dipole (IOD). Winter precipitation atmospheric circulation years IOD concurring with ENSO are compared single or ENSO, to reveal mechanism effects China. The results show that correlation between IOD/ENSO has increased since 1980s. These correlations were significant co-occurrence only, which mainly due lagged thermal dynamic responses an forcing synergy ENSO. positive (PIOD) events can trigger modify anticyclone east India, transports moisture from tropical In addition, Niño strengthen abnormal over Philippines winter, conducive maintain water vapor channel western Pacific Information flow analysis shows causalities enhanced after 1980s, causing increase frequency concurrence. Furthermore, higher PIOD (compared negative La Niña) attained a ratio 2:1 enhancing associated generation interdecadal variability. This study helpful understand mechanisms changes China, improve forecast accuracy extreme events.