Monthly averaged total ozone values measured at Halley station, Antarctica. All measurements are in Dobson Units. These monthly averages are a flat average of any daily average values that exist for each given month; the daily averages are a flat average of the measurements obtained during a particular 24-hour period (UTC). The number of observations may vary from day to day. The Dobson ozone observing season at Halley begins at the end of August and ends in mid April; however, very early and late season observations are made with the Sun at low elevation, and are less accurate than those made during the main observing period of September 6 to April 6. The values for 1956/57 (MacDowall, J., 1962) and 1957-1973 (Farman, J. C. and Hamilton, R. A., 1975) have been approximately corrected from the original using the WMO recommended guidance (Komhyr, W. D., Mateer C. L. and Hudson, R. D., 1993) for the Bass-Paur ozone absorption coefficients. Ozone values from 1973 onwards have been calculated using the Bass-Paur coefficients. The approximation of a US standard atmosphere, which will differ from the Antarctic atmosphere, has been used and the assumed temperature used for the absorption coefficients may be inaccurate.

This dataset provides a 308 year (1703-2010) annual snow accumulation record from the Ferrigno 2010 (F10) ice core. The 136 m core was drilled on the Bryan Coast in Ellsworth Land, West Antarctica, during the austral summer 2010/11. The record was measured using the summer peak in nonsea-salt (nss) SO4, in approximately January to December. Snow accumulation is converted to meters of water equivalent (weq - m) based on measured density profile and correcting for thinning using the Nye model, assuming vertical strain rate. Samples were measured at 5 cm resolution, corresponding to approximately eight samples per year. Funding was provided by the NERC grant NE/J020710/1.

This dataset provides a 298 year (1712-2010) annual snow accumulation record from the Bryan Coast (BC11) ice core. The 140 m core was drilled on the Bryan Coast in Ellsworth Land, West Antarctica, during the austral summer 2010/11. The record was measured using the summer peak in non sea salt (nss) SO4, in approximately January to December. Snow accumulation is converted to meters of water equivalent (weq - m) based on measured density profile and correcting for thinning using the Nye model, assuming vertical strain rate. Samples were measured at 5 cm resolution, corresponding to approximately eight samples per year. Funding was provided by the NERC grant NE/J020710/1.

Seventy-nine Antarctic ice core snow accumulation records were gathered as part of a community led project coordinated by the PAGES Antarctica 2k working group. Individual ice core records (kg m2 yr-1) were normalised relative to a reference period (1960-1990). The normalised records were separated into seven geographical regions and averaged together to form the regional composites. The seven geographical regions are: East Antarctica; Wilkes Land Coast; Weddell Sea Coast; Antarctic Peninsula; West Antarctic Ice Sheet; Victoria Land; and Dronning Maud Land. Full data description and methods can be found in Thomas et al., 2017. This record also includes the original data, from which the composite records were produced. Due to erroneous data contained in the files, this dataset has been superseded by a corrected version. Please use that corrected dataset in preference to this one to avoid the problem. The DOI for the updated data is: 10.5285/cc1d42de-dfe6-40aa-a1a6-d45cb2fc8293

Measurements of water discharge, suspended sediment concentration and electrical conductivity during the melt seasons of 2009, 2010, 2011 and 2012 in the proglacial river draining from the tongue of Leverett Glacier, a land-terminating glacier in the south-west of the Greenland Ice Sheet. The measurements were made in a stable bedrock section approximately 2 km downstream from the glacier terminus. Data loggers recorded measurements every 15 minutes from approximately May to August each year. Water depth (stage) was converted to discharge (Q) using season-specific ratings curves derived from repeat dye-dilution injections undertaken across the stage values. Suspended sediment concentration (SSC) was obtained by calibrating turbidity sensor readings with sediment samples taken in-situ and then filtered, dried and weighed. Electrical conductivity (EC) was recorded using a water conductivity probe; the data were filtered for bad values and corrected for temperature, but no smoothing was applied. These version 2 files are presented as CSV lists, with some summary metadata included as comments at the start of each file; they essentially contain the same data as the previous version files.

Auroral oval boundary locations derived from IMAGE (Imager for Magnetopause-to-Aurora Global Exploration) satellite FUV (Far Ultra Violet imager) data covering the period from May 2000 until October 2002. Three sets of boundary data were derived separately from the WIC (Wideband Imaging Camera) and SI12/SI13 (Spectrographic Imager 121.8/135.6 nm) detectors. For each image, the position of each pixel in AACGM (Altitude Adjusted Corrected Geomagnetic) coordinates was established. Each image was then divided into 24 segments covering 1 hour of magnetic local time (MLT). For each MLT segment, an intensity profile was constructed by finding the average intensity across bins of 1 degree magnetic latitude in the range of 50 to 90 degrees (AACGM). Two functions were fit to each intensity profile: a function with one Gaussian component and a quadratic background, and a function with two Gaussian components and a quadratic background. The function with a single Gaussian component should provide a reasonable model when the auroral emission forms in a continuous oval. When the oval shows bifurcation, the function with two Gaussian components may provide a better model of the auroral emission. Of the two functions fit to each intensity profile, we determine the one with the lower reduced chi-square goodness-of-fit statistic to be the better model for that profile. For the version 1.1 boundary location data, the fitting process was performed over 200 iterations to achieve each fit. The auroral boundaries were then determined to be the position of the peak of the poleward Gaussian curve, plus its FWHM (full-width half-maximum) value of the Gaussian, to the peak of the equatorward Gaussian, minus its FWHM. In the case of the single Gaussian fit, the same curve is used for both boundaries. A number of criteria were applied to discard poorly located auroral boundaries arising from either poor fitting or incomplete data. A further correction can be applied to the data, to estimate the location of the Earth''s magnetic field''s OCB (open-close boundary). These corrections have been tabulated in a separate file; if this correction is required the adjustments should be made to the poleward boundary value.

This dataset provides a 308 year record of methansulphonic acid (MSA) from coastal West Antarctica, representing sea ice conditions in the Amundsen-Ross Sea. Annual average MSA has been calculated from the 136 m Ferrigno ice core (F10), drilled on the Bryan Coast in Ellsworth Land, West Antarctica during the austral summer 2010/11. The sea ice extent is based on geometric mean regression of MSA flux with satellite sea ice extent from 146 degrees west. The record was measured using a Dionex ICS2500 anion system at 5 cm resolution, corresponding to approximately 14 samples a year. Funding was provided by the NERC grant NE/J020710/1.

Seventy-nine Antarctic ice core snow accumulation records were gathered as part of a community led project coordinated by the PAGES Antarctica 2k working group. Individual ice core records (kg m2 yr-1) were normalised relative to a reference period (1960-1990). The normalised records were separated into seven geographical regions and averaged together to form the regional composites. The seven geographical regions are: East Antarctica; Wilkes Land Coast; Weddell Sea Coast; Antarctic Peninsula; West Antarctic Ice Sheet; Victoria Land; and Dronning Maud Land. Full data description and methods can be found in Thomas et al., 2017. This record also includes the original data, from which the composite records were produced. This dataset represents an updated version of another published dataset. The update was necessary due to erroneous data contained in the files. Please use this corrected dataset in preference to the other one.

The datasets are temperature time series from thermistor strings installed into two boreholes drilled to a depth of ~7 m in the northern sector of Larsen C Ice Shelf, Antarctica. Supporting borehole information is presented by Ashmore and others (2017). These data are part of the NERC-funded MIDAS (''Impact of surface melt and ponding on ice shelf dynamics and stability'') research project, with grant references NE/L006707/1 and NE/L005409/1. Associated (longer) borehole temperature records, OPTV logs and density records are also available, as are other MIDAS datasets.

This dataset provides an annual snow accumulation record from the Gomez (GZ07) ice core, dating back to the 1850s. The 136 m core was drilled on the South-western Antarctic Peninsula, during January 2007. The annual accumulation record was derived using two methods: a winter-winter value determined from the winter trough in H2O2 and nonsea-salt (nns) SO4 and a summer-summer value based on the summer peak in H2O2 and nssSO4. Snow accumulation is converted to meters of water equivalent (weq - m) based on measured density profile and correcting for thinning using the Nye model, assuming a linear vertical strain rate through the total depth of the core. The samples were analysed at very high resolution (approximately 10 mm, average 90 samples per year) using the Continuous Flow Analysis with Trace Elements-Dual (CFA-TED) method. The temporal length of the core is 152 years, encompassing 1855-2006 and the estimated uncertainty in the dating is plus/minus 1 year from 1855 to 1875 and less than 1 year from 1875 to 2006.