There is clear evidence that the West Antarctic Ice Sheet is contributing to sea-level rise. In contrast, West Antarctic temperature changes in recent decades remain uncertain. West Antarctica has probably warmed since the 1950s, but there is disagreement regarding the magnitude, seasonality and spatial extent of this warming. This is primarily because long-term near-surface temperature observations are restricted to Byrd Station in central West Antarctica, a data set with substantial gaps. Here, we present a complete temperature record for Byrd Station, in which observations have been corrected, and gaps have been filled using global reanalysis data and spatial interpolation. The record reveals a linear increase in annual temperature between 1958 and 2010 by 2.4±1.2 • C, establishing central West Antarctica as one of the fastest-warming regions globally. We confirm previous reports of West Antarctic warming, in annual average and in austral spring and winter, but find substantially larger temperature increases. In contrast to previous studies, we report statistically significant warming during austral summer, particularly in December-January, the peak of the melting season. A continued rise in summer temperatures could lead to more frequent and extensive episodes of surface melting of the West Antarctic Ice Sheet. These results argue for a robust long-term meteorological observation network in the region.

Antarctica boasts one of the world's harshest environments. Since the earliest expeditions, a major challenge has been to characterize the surface meteorology around the continent. In 1980, the University of Wisconsin—Madison (UW-Madison) took over the U.S. Antarctic Program (USAP) Automatic Weather Station (AWS) program. Since then, the UW-Madison AWS network has aided in the understanding of unique Antarctic weather and climate. This paper summarizes the development of the UW-Madison AWS network, issues related to instrumentation and data quality, and some of the ways these observations have and continue to benefit scientific investigations and operational meteorology.

Measuring snowfall in the polar regions is an issue met with many complications. Across the Antarctic, ground-based precipitation measurements are only available from a sparse network of manned stations or field studies. Measurements from satellites promise to fill in gaps in time and space but are still in the early stages of development and require surface measurements for proper validation. Currently, measurements of accumulation from automated reporting stations are the only available means of tracking snow depth change over a broad area of the continent. The challenge remains in determining the cause of depth change by partitioning the impacts of blowing snow and precipitation. While a methodology for separating these two factors has yet to be developed, by comparing accumulation measurements with meteorological measurements, an assessment of whether these terms were a factor in snow depth change during an event can be made. This paper describes a field study undertaken between January 2005 and October 2006 designed to identify the influences of precipitation and horizontal snow transport on surface accumulation. Seven acoustic depth gauges were deployed at automatic weather stations (AWS) across the Ross Ice Shelf and Ross Sea regions of Antarctica to measure net accumulation changes. From these measurements, episodic events were identified and were compared with data from the AWS to determine the primary cause of depth change—precipitation or horizontal snow transport. Information regarding the local impacts of these two terms, as well as climatological information regarding snow depth change across this region, is also provided.

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In our Article presenting a reconstruction of the near-surface temperature record at Byrd Station, a calculation error led to an overestimation of the magnitude and statistical significance of the temperature trends in December-January shown in Fig. 3a,b and Supplementary Table S1. For 1958For -2010, the 'DJ' trend should have been 0.34 ± 0.24 °C per decade, instead of 0.45 ± 0.29 °C per decade, although the significance remained unchanged at the 99% level (P<0.01). For 1980-2010, the trend should have been 0.29 ± 0.53 °C per decade, instead of 0.76 ± 0.66 °C per decade, and thus was not statistically significant. As a result, the last sentence of the section entitled "Temperature trends at Byrd Station", referring to the significance of the trends during 1980-2010, should not include "except for December-January". This calculation error had no bearing on the other trends discussed in the paper.Furthermore, the reconstruction was done, in part, by merging temperature observations from the staffed Byrd Station established in 1957 and occupied year-round until the early 1970s, with temperatures recorded by the automatic weather station in operation since 1980. These observations were based on monthly mean temperatures compiled by the Antarctic READER Project 1 . Whenever possible, READER uses six-hourly data to compute the monthly means in an effort to produce consistent meteorological time series for Antarctica. Because six-hourly data were not found for Byrd for the years 1957 to 1975, the monthly means reported by READER for this period were taken from a previous compilation of Antarctic temperatures 2 based on monthly reports published in the Monthly Climatic Data for the World or the World Weather Records. One concern about these reports was the lack of information regarding the methodology used to derive the monthly means.In early 2013, we discovered previously unused sub-daily meteorological observations from Byrd Station for the period 1957-75 on the website of the National Climatic Data Center. This data set had been available for a few years but was overlooked during our reconstruction efforts. Using this data, we have recalculated the monthly mean temperatures from 1957 to 1975 in a manner consistent with the more recent portion of the Byrd record. For the period running from October to March, the recalculation yields higher temperatures (by 0.3 °C on average) than those previously published by READER, with virtually no effect (<0.1 °C) during the rest of the year. These discrepancies are likely to stem from the use of daily minima and maxima for the monthly reports published in the 1950s to 1970s, in conjunction with the effects of the diurnal cycle of air temperature during the sunlit part of the year. Both our temperature reconstruction (http://polarmet.osu.edu/Byrd_recon/) and the READER database have since been updated to incorporate these changes.This update reduces the magnitude of the long-term warming trend at Byrd (Fig. 3a). The 1958-2010 annual trend is lowered by around 10% (from 0.47 ± 0....

Two years of automatic weather station observations describing the linkage between the inland confluence zone and the intense coastal katabatic wind regime at Terra Nova Bay, Antarctica, are analyzed. A highly stable wind regime is described by the data with the air over the plateau converging into the head of Reeves Glacier, descending dry adiabatically to the Nansen Ice Sheet, and apparently accelerating horizontally down the local pressure gradient to Inexpressible Island, which is situated along the western shore of Terra Nova Bay. This low-level jet of cold air is laterally confined and is only slightly responsive to synoptic forcing. The internal dynamics of the airstream is the dominant factor determining its behavior. Lateral fluctuations in the katabatic wind are primarily controlled by buoyancy variations.