Influences on the Changes of PDO and AMO from Volcanic Eruptions in Distinct Latitudes with Different Magnitudes

Abstract:

Influences on the Changes of PDO and AMO from Volcanic Eruptions in Distinct Latitudes with Different Magnitudes

Kefan CHEN¹⁺, Liang NING^2#, Zhengyu LIU³, Jian LIU¹, Mi YAN¹, Weiyi SUN^1
1Nanjing Normal University, China, ²NANJING NORMAL UNIVERSITY, China, ³The Ohio State University, United States

In this study, the influences on the variations of the Pacific Decadal Oscillation (PDO) and Atlantic Multi-Decadal Oscillation (AMO) from volcanic eruptions in different latitudes (i.e., northern, southern and tropical volcanic eruptions) with different magnitudes (i.e., less than 25Tg, 25-50Tg, 50-100Tg, and more than 100Tg) were investigated through the Community Earth System Model-Last Millennium Ensemble (CESM-LME) achieve as well as four groups of volcanic sensitivity experiments based on the Community Earth System Model (CESM). The results showed that, volcanic eruptions in the past millennium can trigger negative PDO and AMO phases when the magnitudes of the eruptions are larger than 50Tg. Both the length and persistence of the negative PDO and AMO phases depend linearly on the intensity of the eruptions. These findings are correlated with the results in the four groups of volcanic sensitivity experiments in which volcanic eruptions of 25Tg, 50Tg, 100Tg and 200Tg was implemented, respectively. On account of this, volcanic eruptions in different latitudes have distinct impacts on PDO and AMO either. Southern volcanic eruptions usually have relative stronger impacts on the occurrence of negative PDO phases, while northern and equator volcanic eruptions less than 50Tg are more likely to induce positive PDO phases. Furthermore, northern and equator volcanic eruptions are more likely to trigger negative AMO phases compared with the southern volcanic eruptions.