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Despite a variety of efforts made to measure snow accumulation at the South Pole (SP), snow accumulation changes and their mechanism have not yet been fully explained. Here, SP stake farm measurements, global sea surface temperature observations, and atmospheric circulation data from European Centre for Medium‐Range Weather Forecasts Reanalysis version 5 were used to investigate the annual and seasonal snow accumulation changes at the SP during 1983–2020, and their association with central tropical Pacific Sea surface temperature variations. SP annual snow accumulation decreased significantly for the 1983–2007 period at a rate of −39.7 ± 1.4 mm decade⁻¹, but switched to a dramatically positive trend during 2008–2020 (108.7 ± 2.7 mm decade⁻¹), with the strongest increase in the austral autumn. The switch to a dramatically upward trend can largely be attributed to a cyclonic anomaly over the South Atlantic and an anticyclonic anomaly over the Drake Passage, causing the enhanced advection of warm and wet air into the SP. These circulation patterns were generated by an atmospheric Rossby wave train forced by rapid warming in the central tropical Pacific during 2008–2020.

 

Abstract. A new meteorological dataset derived from records of Antarctic automatic weather stations (here called the AntAWS dataset) at 3 h, daily and monthly resolutions including quality control information is presented here. This dataset integrates the measurements ofair temperature, air pressure, relative humidity, and wind speed anddirection from 267 Antarctic AWSs obtained from 1980 to 2021. The AWS spatial distribution remains heterogeneous, with the majority of instrumentslocated in near-coastal areas and only a few inland on the East Antarctic Plateau. Among these 267 AWSs, 63 have been operating for more than 20 years and 27 of them in excess of more than 30 years. Of the fivemeteorological parameters, the measurements of air temperature have the bestcontinuity and the highest data integrity. The overarching aim of thiscomprehensive compilation of AWS observations is to make these data easilyand widely accessible for efficient use in local, regional and continentalstudies; it may be accessed at https://doi.org/10.48567/key7-ch19 (Wang et al., 2022). This dataset isinvaluable for improved characterization of the surface climatology acrossthe Antarctic continent, to improve our understanding of Antarctic surfacesnow–atmosphere interactions including precipitation events associated with atmospheric rivers and to evaluate regional climate models ormeteorological reanalysis products. 

Abstract From 5 July to 11 September 2012, the Amundsen–Scott South Pole station experienced an unprecedented 78 days in a row with a maximum temperature at or below −50°C. Aircraft and ground-based activity cannot function without risk below this temperature. Lengthy periods of extreme cold temperatures are characterized by a drop in pressure of around 15 hPa over 4 days, accompanied by winds from grid east. Periodic influxes of warm air from the Weddell Sea raise the temperature as the wind shifts to grid north. The end of the event occurs when the temperature increase is enough to move past the −50°C threshold. This study also examines the length of extreme cold periods. The number of days below −50°C in early winter has been decreasing since 1999, and this trend is statistically significant at the 5% level. Late winter shows an increase in the number of days below −50°C for the same period, but this trend is not statistically significant. Changes in the southern annular mode, El Niño–Southern Oscillation, and the interdecadal Pacific oscillation/tripole index are investigated in relation to the initiation of extreme cold events. None of the correlations are statistically significant. A positive southern annular mode and a La Niña event or a central Pacific El Niño–Southern Oscillation pattern would position the upper-level circulation to favor a strong, symmetrical polar vortex with strong westerlies over the Southern Ocean, leading to a cold pattern over the South Pole. Significance Statement The Amundsen–Scott South Pole station is the coldest Antarctic station staffed year-round by U.S. personnel. Access to the station is primarily by airplane, especially during the winter months. Ambient temperature limits air access as planes cannot operate at minimum temperatures below −50°C. The station gets supplies during the winter months if needed, and medical emergencies can happen requiring evacuations. Knowing when planes would be able to fly is crucial, especially for life-saving efforts. During 2012, a record 78 continuous days of temperatures below −50°C occurred. A positive southern annular mode denoting strong westerly winds over the Pacific Ocean and a strong polar vortex over the South Pole contribute to the maintenance of long periods of extremely cold temperatures. 

The interior of Dronning Maud Land (DML) in East Antarctica is one of the most data-sparse regions of Antarctica for studying climate change. A monthly mean near-surface temperature dataset for the last 30 years has been compiled from the historical records from automatic weather stations (AWSs) at three sites in the region (Mizuho, Relay Station, and Dome Fuji). Multiple AWSs have been installed along the route to Dome Fuji since the 1990s, and observations have continued to the present day. The use of passive-ventilated radiation shields for the temperature sensors at the AWSs may have caused a warm bias in the temperature measurements, however, due to insufficient ventilation in the summer, when solar radiation is high and winds are low. In this study, these warm biases are quantified by comparison with temperature measurements with an aspirated shield and subsequently removed using a regression model. Systematic error resulting from changes in the sensor height due to accumulating snow was insignificant in our study area. Several other systematic errors occurring in the early days of the AWS systems were identified and corrected. After the corrections, multiple AWS records were integrated to create a time series for each station. The percentage of missing data over the three decades was 21% for Relay Station and 28% for Dome Fuji. The missing rate at Mizuho was 49%, more than double that at Relay Station. These new records allow for the study of temperature variability and change in DML, where climate change has so far been largely unexplored.

Antarctic climate change has been studied using temperature data at staffed stations. The staffed stations, however, are mainly located on the Antarctic Peninsula and in the coastal regions. Climate change is largely unknown in the Antarctic plateau, particularly in the western sector of the East Antarctic Plateau in areas such as the interior of Dronning Maud Land (DML). To fill the data gap, this study presents a new dataset of monthly mean near-surface climate data using historical observations from three automatic weather stations (AWSs). This dataset allows us to study temperature variability and change over a data-sparse region where climate change has been largely unexplored.