Sedimentary U37K′ ${\mathbf{U}}_{\mathbf{37}}^{\mathbf{K}\prime }$ in the South China Sea Reflects Mean Sea Surface Temperatures Despite Substantial Winter Monsoon‐Driven Alkenone Flux Variability

Chung, Chia‐YuChia‐YuChungHo, Sze LingSze LingHo2025-10-302025-10-302025-09-16https://www.scopus.com/pages/publications/105016383785?origin=resultslisthttps://scholars.lib.ntu.edu.tw/handle/123456789/733291The alkenone-based (Formula presented.) index is widely used to reconstruct sea surface temperature (SST), including past SST variability associated with the East Asian Winter Monsoon (EAWM). However, its ability to record and preserve seasonal signals remains uncertain. Here, we present alkenone flux and (Formula presented.) temperature data from two sediment traps in the oligotrophic northern South China Sea (SCS). The (Formula presented.) records show dampened seasonal variability and temporal lags compared to the weekly SST record, resembling time-averaged SST over 20–40 weeks, which indicates long residence times of alkenones. High (Formula presented.) temperatures during winter suggest that the winter flux contains material produced outside of winter and/or transported from adjacent continental shelf. Consequently, flux-weighted (Formula presented.) temperatures align closely with annual mean SSTs, despite elevated alkenone flux during the EAWM months. These findings suggest that (Formula presented.) -based reconstructions in the northern SCS likely reflect annual mean condition rather than EAWM variability.alkenoneEast Asian Winter MonsoonSouth China SeaU37K′Sedimentary U37K′ ${\mathbf{U}}_{\mathbf{37}}^{\mathbf{K}\prime }$ in the South China Sea Reflects Mean Sea Surface Temperatures Despite Substantial Winter Monsoon‐Driven Alkenone Flux Variabilityjournal article10.1029/2025gl117936