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    Radiolarians (holoplanktonic Protozoa) found in marine sediments are commonly used in Southern Ocean as palaeoclimate proxies. Generating such reconstructions of past climate based on radiolarian abundances requires a spatially and environmentally comprehensive reference dataset of modern radiolarian census counts. The Southern Ocean RADiolarian (SO-RAD) dataset includes census counts for 237 radiolarian taxa from 228 surface sediment samples located in the Atlantic, Indian and South-west Pacific sectors of the Southern Ocean. This compilation is the largest radiolarian census dataset derived from surface sediment samples in the Southern Ocean. The SO-RAD dataset may be used as a reference dataset for palaeoceanographic reconstructions, or for studying modern radiolarian biogeography and species diversity. RELATED PUBLICATION: https://doi.org/10.5194/essd-13-5441-2021

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    Diatom census counts were used to quantitatively estimate summer sea-surface temperatures (SST) over the last 40,000 years in core MD11-3353, collected in 2011 on board the R.V. Marion Dusfresne west of Kerguelen Island, Southern Ocean. The transfer function used to reconstruct summer (January to March) SST is the Modern Analog Technique that here uses 249 surface sediment samples (modern analogs), the relative abundances of 32 diatom species and the chord distance to select the five most similar modern analogs (Crosta et al., 2020). This method yields a root mean square error of prediction of ~1 °C. The core chronology is detailed in Thöle et al. (2019). RELATED PUBLICATION: Civel-Mazens, Matthieu; Crosta, Xavier; Cortese, Giuseppe; Michel, Elisabeth; Mazaud, Alain; Ther, Olivier; Ikehara, Minoru; Itaki, Takuya (2021): Impact of the Agulhas Return Current on the oceanography of the Kerguelen Plateau region, Southern Ocean, over the last 40 kyrs. Quaternary Science Reviews, 251, 106711, https://doi.org/10.1016/j.quascirev.2020.106711

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    Here, we present new, transient, GCM-forced ice-sheet simulations validated against proxy reconstructions. This is the first time such an evaluation has been attempted. Our empirically constrained simulations indicate that the AIS contributed 4 m to global mean sea level by 126 ka BP, with ice lost primarily from the Amundsen, but not Ross or Weddell Sea, sectors. We resolve the conflict between previous work and show that the AIS thinned in the Wilkes Subglacial Basin but did not retreat. We also find that the West AIS may be predisposed to future collapse even in the absence of further environmental change, consistent with previous studies. There are two files, for Termination 1 ('T1') and Termination 2 ('T2'). They contain spatial fields for ice thickness, ice surface elevation, bedrock elevation, surface and basal velocity, and mask. The T1 outputs are every 500 years, whereas the T2 outputs are every 100 years. The spatial resolution of both is 20 km. Sea-level-equivalent mass loss can be calculated from these outputs, but is also provided here in a text file for convenience. RELATED PUBLICATION: Golledge, N.R., Clark, P.U., He, F., et al. (2021). Retreat of the Antarctic Ice Sheet During the Last Interglaciation and Implications for Future Change. Geophysical Research Letters, 48(17). https://doi.org/10.1029/2021GL094513 GET DATA: https://doi.org/10.17605/OSF.IO/GZB3H