Trends in south pole particle concentrations imply holocene westerly wind strengthening

Abstract

The Southern Hemisphere Westerly Winds (SHWW) play an important role in global climate and Antarctic ice sheet dynamics; however, high-resolution proxy reconstructions are sparse. Conflicting evidence suggests SHWW latitudinal change, weakening and/or strengthening, throughout the Holocene. Dust microparticle characteristics preserved in Antarctic ice cores (i.e., changes in concentration and size) provide a useful physical proxy reflecting wind dynamics. We present South Pole Ice Core (SPC14) dust records spanning the Holocene. Dust concentrations (1.1–5.1 µm) decrease through the Holocene, while the coarse particle percentage (CPP) increase due to a relatively larger decrease in finer (1.1–3.2 µm) dust, highlighting an opposing trend. The South Pole dust trends, consistent with CMIP6-PMIP4 model trends, southern mid-latitude insolation, and mid- to high latitude Southern Hemisphere proxy records, reflect SHWW southward migration and strengthening of wind speed south of 51° S during the mid-Holocene (∼ 7000–3000 years ago). Our findings suggest orbitally-driven warming throughout the Holocene led to strengthening and southward migration of the SHWW beginning ∼ 7000 years BP.