Correlating strong volcano eruptions and ENSO events 1525—2000

Strong volcanic eruptions (VEI(volcanicexplosivityindex)≥4) from 1525—2000 were extracted from dataset provided by Smithsonian Institution Global Volcanic Programme. Volcanice ruptions were divided into 2 types: eruptions with IVE =4), and eruptions with IVE ≥5. ENSO chronology reconstructed by Gergis was used to divide ENSO into 2 types: El Nino and LaNina. Ten year cumulative numbers of large volcanic eruption and ENSO events were analyzed. Then strong volcanic eruptions were matched with ENSO from 1525 to 2000. A total of 193 strong volcanic eruptions from 1525 — 2000 were identified: 153 eruptions with IVE of 4, and 42 eruptions with IVE≥5. A total of 399 ENSO events were found: 188 ElNino events and 211 LaNina events. The number of ENSO events within 2 years after strong volcanic eruptions was significantly more than ENSO events without strong volcanic eruptions within 2 years earlier. After strong volcanice ruptions, ElNino and La Nina had about equivalent numbers: 137 ElNino events and 136 La Nina events. However, the number of La Nina without large volcanic eruptions within the 2 years earlier was significantly more than ElNino. The number of ElNino events and LaNina events were almost identical after volcano eruptions of IVE=4 and IVE≥5.