https://doi.pangaea.de/10.1594/PANGAEA.993404Hess, Anya VAnya VHess0000-0001-9272-2534Woods Hole Oceanographic InstitutionGeorge Mason UniversityWang, ShouyiShouyiWang0000-0002-9046-6474Woods Hole Oceanographic InstitutionUniversity of Colorado, BoulderUmmenhofer, Caroline CCaroline CUmmenhoferWoods Hole Oceanographic InstitutionRosenthal, YairYairRosenthal0000-0002-7546-6011The State University of New JerseyOppo, Delia WDelia WOppo0000-0003-2946-5904Woods Hole Oceanographic InstitutionPANGAEA2026ForaminiferaIndonesian ThroughflowLittle Ice Agemedieval climate anomalyMg/CaMg/Ca planktonic foraminiferaPacific Water CirculationPulleniatina obliquiloculataThermoclinethermocline depththermocline water temperatureCampaignSiteCalendar age, medianSea surface temperatureThermocline water temperatureTemperature, differenceDataset10.1029/2002PA00084610.1002/2017PA00312210.5194/gchron-3-149-202110.1029/2006GL02723410.1038/nature0823310.1126/science.aac993710.1002/2014GL06145027852 data pointstext/tab-separated-valuesCreative Commons Attribution 4.0 InternationalData access is restricted (moratorium, sensitive data, license constraints)This data accompanies Hess et al. (2026, Science Advances). It consists of Last Millennium (750 CE to present) surface-thermocline temperature differences from the Indonesian Seas, calculated from Mg/Ca-derived sea-surface temperatures (Globigerinoides ruber; Oppo et al., 2009, Esswein, 2012) and thermocline temperatures (Pulleniatina obliquiloculata; Hess et al., 2026). Temperatures derived using the species-specific calibrations of Hollstein et al. (2017). Data from cores recovered in very close proximity to each other have been grouped (Makassar Strait sites BJ8-03 31MC, 32GGC, 34GGC; and Java Sea Sites BJ8-03 6MC, 7GGC) and spliced; multicorer (MC) data were used for the period over which it is available. Ages have been updated to Marine20 and generated, with age uncertainty, using geoChronR (McKay et al., 2021).National Science Foundationhttps://doi.org/10.13039/100000001OCE-2303513