| Summary: | This study gives an overview of the climate effects of explosive volcanic eruptions at the Central American Volcanic Arc (CAVA) for the last 200 ka, obtained during the third phase of the SFB574 project. Major volcanic eruptions in the tropics which directly inject high SO2 amounts into the stratosphere have a significant impact on the global climate. Within weeks the sulfur gases build volcanic sulfate aerosols, which remain in the stratosphere between 3 to 6 years according to the large scale meridional overturning circulation in the stratosphere, called the Brewer-Dobson circulation (BDC). Due to the different strengths of the BDC in the Northern Hemisphere and Southern Hemisphere, and to its seasonality, we find different climate effects between the two hemispheres. To address the role of the seasonality, and eruption strength, we perform a set of model simulations with stratospheric SO2 injections of different magnitudes varying between weak and extremely strong eruptions during different seasons. We particularly address the effects from the stratosphere down to the surface, showing the dominant atmospheric modes during winter: the Northern and Southern Annular Modes (NAM and SAM). We explore the mechanisms for the annular mode volcano response, highlighting atmospheric and oceanic circulation changes and possible implications for ice core proxies.
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