This dataset documents the trends and variability in the latitude and strength of the belt of lower-atmosphere westerly winds over the Southern Ocean, referred to as the ''westerly jet''. Time series of annual mean and seasonal diagnostics are available for the period 1979-present, specifically time series of seasonal and annual mean jet latitude and strength. The diagnostics are derived from the European Centre for Medium Range Weather Forecasts (ECMWF) ERA-Interim reanalysis (for more information see www.ecmwf.int and Dee et al. (2011)), which is an observationally-constrained reconstruction of atmospheric conditions. The broad characterisation of the westerly winds into these simple diagnostics has been found to be useful for understanding long-term climate change due to contrasting drivers of change and impacts on other aspects of the climate system. This is an index of winds around the full circumference of all longitudes at Southern Hemisphere middle latitudes. The exact latitude depends on the position of the jet at any given time, but on average the jet (the core of the westerlies) is located at approximately 52 deg S.

This dataset presents the relative diatom abundances of 55 species/groups from the 132-120 ka interval in marine sediment core TPC288 (-59.14 degN, -37.96 degE). This age interval corresponds to the peak of Marine Isotope Stage 5e (130- 116 ka). Microscope slides were prepared using a method adapted from Scherer (1994) and 300+ diatom valves were counted for each depth sample to produce the relative percentage abundance of each diatom species/group. This project was funded by the UK Natural Environment Research Council Grant NE/L002531/1

This dataset presents the relative diatom abundances of 56 species/groups from the 132-120 ka interval in marine sediment core U1361A (-64.41 oN, 143.89 oE). This age interval corresponds to the peak of Marine Isotope Stage 5e (130- 116 ka). Microscope slides were prepared using a method adapted from Scherer (1994) and 300+ diatom valves were counted for each depth sample to produce the relative percentage abundance of each diatom species/group. This project was funded by the UK Natural Environment Research Council Grant NE/L002531/1

This dataset presents the relative diatom abundances of 55 species/groups from the 132-120 ka interval in marine sediment core TPC290 (-55.55 degN, -45.02 degE). This age interval corresponds to the peak of Marine Isotope Stage 5e (130- 116 ka). Microscope slides were prepared using a method adapted from Scherer (1994) and 300+ diatom valves were counted for each depth sample to produce the relative percentage abundance of each diatom species/group. This project was funded by the UK Natural Environment Research Council Grant NE/L002531/1

This dataset presents the relative diatom abundances of 55 species/groups from the 132-120 ka interval in marine sediment core TPC287 (-60.31 degN, -36.65 degE). This age interval corresponds to the peak of Marine Isotope Stage 5e (130- 116 ka). Microscope slides were prepared using a method adapted from Scherer (1994) and 300+ diatom valves were counted for each depth sample to produce the relative percentage abundance of each diatom species/group. This project was funded by the UK Natural Environment Research Council Grant NE/L002531/1

This dataset presents the relative diatom abundances of 56 species/groups from the 132-120 ka interval in marine sediment core PC509 (-68.31 degN, -86.03 degE). This age interval corresponds to the peak of Marine Isotope Stage 5e (130- 116 ka). Microscope slides were prepared using a method adapted from Scherer (1994) and 300+ diatom valves were counted for each depth sample to produce the relative percentage abundance of each diatom species/group. This project was funded by the UK Natural Environment Research Council Grant NE/L002531/1

This dataset presents the relative diatom abundances of 55 species/groups from the 132-120 ka interval in marine sediment core NBP9802-04 (-64.20 degN, -170.08 degE). This age interval corresponds to the peak of Marine Isotope Stage 5e (130- 116 ka). Microscope slides were prepared using a method adapted from Scherer (1994) and 300+ diatom valves were counted for each depth sample to produce the relative percentage abundance of each diatom species/group. This project was funded by the UK Natural Environment Research Council Grant NE/L002531/1

This dataset presents the relative diatom abundances of 56 species/groups from the 132-120 ka interval in marine sediment core ANTA91-8 (-70.78 degN, 172.83 degE). This age interval corresponds to the peak of Marine Isotope Stage 5e. Microscope slides were prepared using a method adapted from Scherer (1994) and 300+ diatom valves were counted for each depth sample to produce the relative percentage abundance of each diatom species/group. The age model for this dataset has been updated, with new tiepoints between the sediment core magnetic susceptibility and the LR04 benthic delta-O-18 stack selected to improve the graphical alignment. This project was funded by the UK Natural Environment Research Council Grant NE/L002531/1.

Mesopelagic fish were sampled in the Scotia Sea using a 25 m2 opening and closing rectangular midwater trawl during five research cruises on RRS John Biscoe and RRS James Clark Ross. Nets sampled discrete layers, from the surface to 1000 m during austral spring, summer and autumn. The data include 17726 individual fish records from 66 taxa, the most abundant of which were myctophids of the genera Electrona, Gymnoscopelus, Krefftichthys and Protomyctophum and bathylagids (Bathylagus sp.). Length (standard length, total length or pre-anal fin length) was measured for the majority of specimens (16837), with sex and weight data also collected for many. The work was conducted as part of the BAS Ecosystems Programmes funded by the UK Natural Environment Research Council.

We present a new bathymetric compilation of the greater South Georgia region, here defined by a bounding box of ~900km (45W to 19W) by ~580km (63S to 50S) and covering an area of 530,000 km2. The region includes the South Georgia shelf, the Shag Rock shelf (to the west of South Georgia), the surrounding continental slopes and adjacent deep sea. This bathymetry grid was compiled from a variety of different data sources including multibeam swath bathymetry collected from scientific cruises undertaken by British Antarctic Survey (BAS), Alfred Wegener Institute (AWI) and the Institute of Geophysics, University of Texas. The grid has been constructed using a layered hierarchy dependent on accuracy of each dataset. The data is available as a 100m resolution GeoTIFF, ESRI ascii grid or KMZ file of elevation data along with a shapefile indicating the spatial coverage of all the contributing datasets. This work was supported by the National Environmental Research Council (grant number NE/L002531/1). For further information regarding the creation of this dataset please refer to doi:10.1038/srep33163.