South Pacific Convergence Zone (SPCZ) Solomon Islands and Vanuatu sediment core age models

Data from South Pacific Convergence Zone sediment cores collected from five freshwater lakes on Tetepare and Rendova Islands in Solomon Islands, and Thion Island in Vanuatu, record 500 to 1000 years of pre-instrumental precipitation variability. The records are based on the hydrogen isotope composition of the dinoflagellate biomarker dinosterol, which is inversely correlated with mean annual precipitation rates, and provides quantitative records of rainfall rates from the western portion of the SPCZ. Data sets from Harai Lake #1, Barora Pond, Lake Tavara, Red Lake, and White Lake include sediment core age model dates (6 cores: Rendova_SHAR1UC2, Tetepare_SBARUC2, Tetepare_SBARUC3, Tetepare_STAVUC4, Thion_VTRUC3, Thion_VTRUC2), magnetic susceptibility (2 cores: Tetepare_SBARUC2, Tetepare_SBARUC3), d2Hdinosterol and calculated precipitation rates (5 cores: Rendova_SHAR1UC2, Tetepare_SBARUC2, Tetepare_STAVUC4, Thion_VTRUC3, Thion_VTRWUC2), as well as d2Hleaf wax (1 core: Thion_VTWUC2). Our regionally distributed reconstructions indicate that precipitation rates in the western SPCZ were 1 – 2 mm d-1 lower during the Little Ice Age (1450 – 1850 CE) compared to the past 150 years, consistent with a thermodynamic response to global temperatures. These results contrast with the expected drying associated with initial global temperature increases in many climate models. Further anthropogenic climate change and warming seas in the southwest Pacific will likely promote more intense SPCZ precipitation in the future.