Hydroclimate Responses over Global Monsoon Regions Following Volcanic Eruptions at Different Latitudes

Abstract

Understanding the influence of volcanic eruptions on the hydroclimate over global monsoon regions is of great scientific and social importance. However, the link between the latitude of volcanic eruptions and related hydroclimate changes over global monsoon regions in the last millennium remains inconclusive. Here we show divergent hydroclimate responses after different volcanic eruptions based on large sets of reconstructions, observations, and climate model simulation. Both the proxy and observations show that Northern Hemispheric (Southern Hemispheric) monsoon precipitation is weakened by northern (southern) and tropical eruptions but is enhanced by the southern (northern) eruptions. A similar relationship is found in coupled model simulations driven by volcanic forcing. The model evidence indicates that the dynamic processes related to changes in atmospheric circulation play a dominant role in precipitation responses. The dry conditions over the Northern Hemisphere (Southern Hemisphere) and global monsoon regions following northern (southern) and tropical eruptions are induced through weakened monsoon circulation. The wet conditions over Northern Hemispheric (Southern Hemispheric) monsoon regions after southern (northern) eruptions are caused by the enhanced cross-equator flow. We extend our model simulation analysis from mean state precipitation to extreme precipitation and find that the response of the extreme precipitation is consistent with that of the mean precipitation but is more sensitive over monsoon regions. The response of surface runoff and net primary production is stronger than that of precipitation over some submonsoon regions. Our results imply that it is imperative to consider the potential volcanic eruptions at different hemispheres in the design of near-term decadal climate prediction experiments.

Wetter Global Arid Regions Driven by Volcanic Eruptions

“…As in Zuo et al (2019), we used the "superposed epoch analysis (SEA)" method, which average the precipitation response to multiple volcanic eruptions to reduce internal variability (Adams et al, 2003;Anchukaitis et al, 2010;Haurwitz & Brier, 1981). We focus on the hydroclimate response in the first local summer after volcanic eruptions; the anomalies are calculated with respect to 5-year preeruption mean (Fischer et al, 2007;Iles et al, 2013).…”

“…For proxy and instrumental datasets which cover different time periods, we use a lower threshold of 5Tg (trillion gram) and 3Tg, respectively, to include more volcanic events. This criterion is the same as that in Zuo et al (2019). The selected volcanic eruptions in model simulations and observations are shown in Table S1 and S2, respectively.…”

Elevation‐dependent cooling caused by volcanic eruptions during the last millennium

“…Previous studies on the influence of volcanic eruptions have mainly focused on surface temperatures at the global or continent scale (e.g., Wang et al ., ; Zanchettin et al ., ; Zuo et al ., ). Little attention has been paid to the differential response of high‐elevation regions to severe volcanic eruptions.…”

Variabilidade paleoclimática do sistema de Monção Sul-Americano no Centro-Leste do Brasil durante os anos de 1255-2016 (CE) a partir de registros em estalagmites e troncos de árvores

“…Os aerossóis de sulfato maiores que 1μm atuam na dispersão da radiação solar incidente que resulta no aquecimento da estratosfera e consequente resfriamento acentuado na troposfera do hemisfério onde ocorreua erupção vulcânica (Robock, 1995;Stenchikov et al, 1998). Este resfriamento anômalo afeta o ciclo hidrológico das monções regionais do globo ao causar diferença no balanço de energia inter-hemisférico, que por sua vez, acarreta no ano hidrológico seguinte: i) o deslocamento da ZCIT para o hemisfério oposto ao resfriamento (Colose et al, 2016a), ii) mudança no gradiente termal entre continente-oceano em ambos os hemisférios (Swingedouw et al, 2017) e iii) intensificação ou enfraquecimento da célula de Walker (Zuo et al, 2019). Assim, um ano após as erupções vulcânicas no Hemisfério Norte (HN) ocorrem estações menos úmida e/ou seca no período das monções do HN e monções intensificadas no Hemisfério Sul (HS), enquanto erupções no HS influenciam na intensificação das monções no HN e enfraquecimento das monções no HS.…”

“…Análises de modelos ainda mostram que erupções vulcânicas podem causar eventos extremos de precipitação em monções regionais e provocar inundações (Zuo et al, 2019). Brönnimann et al (2019) mostraram por simulações de modelo acoplado a multiregistros que a última fase do LIA 1808-1835 (CE) foi marcada por cinco grandes erupções vulcânicas que causaram após 2 a 3 anos resfriamento global ~ -0.5°C na temperatura de verão.…”