READER (REference Antarctic Data for Environmental Research) is a project of the Scientific Committee on Antarctic Research (SCAR http://www.scar.org/) and has the goal of creating a high quality, long term dataset of mean surface and upper air meteorological measurements from in-situ Antarctic observing systems. These data will be of value in climate research and climate change investigations. The primary sources of data are the Antarctic research stations and automatic weather stations. Data from mobile platforms, such as ships and drifting buoys are not being collected since our goal is to derive time series of data at fixed locations. Surface and upper air data are being collected and the principal statistics derived are monthly and annual means. Daily data will not be provided in order to keep the data set to a manageable size. With the resources available to the project, it is clearly not possible to collect all the information that could be required by the whole range of investigations into change in the Antarctic. Instead a key set of meteorological variables (surface temperature, mean sea level pressure and surface wind speed, and upper air temperature, geopotential height and wind speed at standard levels) are being assembled and a definitive set of measurements presented for use by researchers. A lot of stations have been operated in the Antarctic over the years; many for quite short periods. However, our goal here is to provide information on the long time series that can provide insight into change in the Antarctic. So to be included, the record from a station must extend for 25 years, although not necessarily in a continuous period, or be currently in operation and have operated for the last 10 years. In READER we have chosen to use only data from year-round stations.

Instrumentation was deployed in the Antarctic Peninsula region to monitor conditions occurring in the region of near-space surrounding the Earth. The opportunity was taken to link into a NASA satellite mission occurring at the same time and with similar goals - to study the dynamics of the Earth-Sun system at a location where the two systems are finely balanced. The experiments have been used to interpret the changes in plasma composition at the same point in space due to solar weather events. A refurbished VLF Doppler receiver was installed at Rothera to measure plasmaspheric electron concentration. The electron number density was determined from analysis of the 15 minute integration providing group delay times, Doppler shift and arrival bearing of whistler-mode signals, of man-made transmissions, from MSK format transmitters from north east America. If you would like more information about the VLF Doppler receiver data that is still being routinely collected at Rothera please contact the UK Polar Data Centre at the British Antarctic Survey.

Ground truth measurements in the form of snow/ice cores were obtained from three sites in 2006: Rothschild Island, Latady Island and Smyley Island. The sites selected corresponded to the position of Automatic Weather Stations (AWS) deployed during the previous season. At both the Rothschild Island and Smyley Island sites the AWS - due to an unprecedented amount of snowfall - had been buried. Therefore, two cores, 8m and 12m in length, were obtained from the approximate position of the AWS, in addition to the sampling of a snow pit. At the Latady Island site, the top 60cm of the 5m AWS was protruding above the surface - again, due to an unprecedented amount of snowfall. A diagonally descending trench was dug to recover the AWS and two cores were collected at this site. This work was carried out as part of a project to understand how air mass origin and meteorology affect the mass accumulation of snow in areas of the Antarctic Peninsula, and how the atmosphere's properties are preserved in the snow, Photographs of the expedition showing the ground layout, the situation of the cores and what was done when they were gathered are available and stored with the data.

The Skiymet meteor radar was deployed at Rothera (68S, 68W) in Feb 2005. The radar measures the winds, waves and tides of the mesosphere and lower thermosphere (MLT) regions of the atmosphere. The radar routinely makes three types of measurement: 1. horizontal winds at heights of ~ 75 - 105 km from the drifting of meteors as they are carried by the winds of the MLT; 2. atmospheric temperature from the decay rate of meteor echoes; 3. meteor fluxes, derived from several thousand meteors per day. The radar has been used with an existing, identical, radar in the Arctic at the conjugate latitude of 68N, 21E (Esrange) to produce accurate climatologies of winds, waves and tides - and to quantify the differences between the Antarctic and Arctic MLT (using identical radars eliminates otherwise problematic measurement biases). Other studies will carefully examine meteor/MF-radar instrument biases and apply a developing technique to continually measure temperature using the decay rate of meteor echoes. The radar complements the existing OH temperature spectrometer and imaging airglow camera at Rothera.

Three micro-power Automatic Weather Stations (AWS) with two sonic ranging sensors were deployed at field-sites situated at Rothschild Island, Latady Island and Smyley Island in January 2005. The AWS instruments included a wind vane and two humicaps on the mast and two sonic ranging sensors mounted on separate horizontal scaffold poles. The AWS data collected contributed to a project concerned with understanding how air mass origin and meteorology affect the mass accumulation of snow in areas of the Antarctic Peninsula, and how the atmosphere's properties are preserved in the snow.

The data set comprises high-time resolution meteor wind velocity data from the southern hemisphere Falkland Islands radar (FIR), part of the Super Dual Auroral Radar Network (SuperDARN). The velocities are line-of-sight velocities aligned in the geographic meridional direction (from FIR beam 6, range gate 4). The data cover the interval from 2010 to 2011 inclusive. Funding was provided by BAS national capability funding. NERC grant NE/R016038/1 - National Capability - Polar Expertise Supporting UK Research.

High-resolution simulations of extreme warm temperature events over South Georgia Islands using the UK Met Office Unified Model (MetUM) were conducted at the British Antarctic Survey. The simulations are conducted for the period 1 to 17 January 1991, which included an event in which the temperature at Signy station peaked at 17.4 degrees Celsius on 13 January 1991, as well as a series of consecutive warm events preceding this. The dataset consists of 1) 10 m zonal wind, 10 m meridional wind, 1.5 m temperature, 1.5 m dew point temperature, 1.5 m relative humidity, and mean sea level pressure at a temporal resolution of every 1 hr for the period 1 to 17 January, 2) zonal wind, meridional wind, vertical wind, and potential temperature on model levels at 00UTC 13 January, and 3) rainfall rate at 00 UTC 13 January (averaged over a 3-hr period). The MetUM is run over a domain that includes South Orkney Islands and the surrounding ocean, which comprises 120 x 120 grid points at a grid spacing of 1 km. The model output is used to investigate the detailed influence of South Orkney Islands orography on temperature, precipitation, and winds, and in particular the importance of foehn events in producing extreme warm temperatures at Signy station. Funding: 1) Core funding from the Natural Environment Research Council (NERC) to the Atmosphere, Ice and Climate Programme of British Antarctic Survey (BAS). 2) NERC National Capability International grant SURface FluxEs In AnTarctica (NE/X009319/1). 3) European Union's Horizon 2020 research and innovation framework programme under Grant agreement no. 101003590 (PolarRES).

The data consists of a CSV file of mean sea level pressure (MSLP, in hPa), 1.25 m temperature (in celsius), 10 m wind speed (in knots), 10 m wind direction (in degrees), and relative humidity (in percent) measured at Signy Station (Latitude 60 degress 43'0"S, Longitude 45 degrees 36'0"W) for the period of 1947 - 1994. These data were used by Lu et al. (2023) to study extreme high temperature events in the South Orkney Islands (SOIs). Funding was provided by the Natural Environment Research Council (NERC) to the Atmosphere, Ice and Climate Programme of British Antarctic Survey (BAS), NERC National Capability International grant SURface FluxEs In AnTarctica (NE/X009319/1) and the European Union's Horizon 2020 research and innovation framework programme under Grant agreement no. 101003590 (PolarRES).

The dataset is the output of a statistical model which downscales ERA5 monthly precipitation data using gauge measurements from the Upper Beas and Sutlej Basins in the Western Himalayas. Multi-Fidelity Gaussian Processes (MFGPs) are used to generate more accurate precipitation values between 1980 and 2012, including over ungauged areas of the basins. MFGPs are a probabilistic machine learning method that provides principled uncertainty estimates via the prediction of probability distributions. These predictions can therefore be used to estimate the likelihood of extreme precipitation events which have led to droughts, floods, and landslides. Funding from UK Engineering and Physical Sciences Research Council [grant number: 2270379].

Drift-averaged pitch angle diffusion coefficients, and derived pitch angle distributions and loss timescales for electrons with energies from 100 keV to 4 MeV, L* in the range 2 to 7 and geomagnetic activity determined by the Kp index. The pitch angle distributions and loss timescales, for use in radiation belt models, are calculated from the diffusion coefficients assuming pure pitch angle diffusion and steady decay of the distribution. Funding was provided by NERC grant NE/V00249X/1 (Sat-Risk)