Assessing the impact of large volcanic eruptions of the last millennium (850–1850 CE) on Australian rainfall regimes

Stephanie A. P. Blake, Sophie C. Lewis, Allegra N. LeGrande, Ron L. Miller
2018 Climate of the Past  
<p><strong>Abstract.</strong> Explosive volcanism is an important natural climate forcing, impacting global surface temperatures and regional precipitation. Although previous studies have investigated aspects of the impact of tropical volcanism on various ocean–atmosphere systems and regional climate regimes, volcanic eruptions remain a poorly understood climate forcing and climatic responses are not well constrained. In this study, volcanic eruptions are explored in particular reference to
more » ... ralian precipitation, and both the Indian Ocean Dipole (IOD) and El Niño–Southern Oscillation (ENSO). Using nine realisations of the last millennium (LM) (850–1850<span class="thinspace"></span>CE) with different time-evolving forcing combinations, from the NASA GISS ModelE2-R, the impact of the six largest tropical volcanic eruptions of this period are investigated. Overall, we find that volcanic aerosol forcing increased the likelihood of El Niño and positive IOD conditions for up to four years following an eruption, and resulted in positive precipitation anomalies over north-west (NW) and south-east (SE) Australia. Larger atmospheric sulfate loading during larger volcanic eruptions coincided with more persistent positive IOD and El Niño conditions, enhanced positive precipitation anomalies over NW Australia, and dampened precipitation anomalies over SE Australia.</p>
doi:10.5194/cp-14-811-2018 fatcat:rcpvskgrwnc55ideatl7dsrh4m