Imprints of Sea Ice, Wind Patterns, and Atmospheric Systems on Summer Water Isotope Signatures at Hercules Névé, East Antarctica

Abstract. This study investigated the interactions between atmospheric and oceanic conditions during the austral summer based on an analysis of water isotopes (δ¹⁸O, δ²H, and deuterium excess[dexc]) in a Hercules Névé ice core from Antarctica. The primary objective was to evaluate the complex influence of temperature, precipitation, wind patterns (v- and u-winds), ocean environmental (sea ice concentration [SIC] and sea surface temperature [SST]), and atmospheric systems (Amundsen Sea Low [ASL] and Zonal Wave-3 [ZW3]) on the variability of these water isotopes using high-resolution ERA5 reanalysis data from the austral summer months between 1979 and 2015. The results indicated that higher temperatures and precipitation increased δ¹⁸O levels, while wind patterns contributed in a complex manner to variation in the isotopes. Specifically, southerly winds (positive u-wind anomalies) increased δ¹⁸O values, whereas westerly winds (positive v-wind anomalies) tended to decrease them as a result of reflecting moisture characteristics. Additionally, the dexc showed positive correlations with SIC and negative correlations with SST, providing valuable insights into moisture source processes in the study region during austral summer. The ASL and ZW3 were thus found to play significant roles in atmospheric circulation, affecting the transport of heat and moisture and leading to isotopic variation.