Description: High temporal resolution (three hours) records of temperature, wind speed and sea level pressure recorded at Antarctic research station Neumayer (708S, 88W) during 1982–2011 are analysed to identify oscillations from daily to intraseasonal timescales. The diurnal cycle dominates the three-hourly time series of temperature during the Antarctic summer and is almost absent during winter. In contrast, the three-hourly time series of wind speed and sea level pressure show a weak diurnal cycle. The dominant pattern of the intraseasonal variability of these quantities, which captures the out-of-phase variation of temperature and wind speed with sea level pressure, shows enhanced variability at timescales of , 40 days and , 80 days, respectively. Correlation and composite analysis reveal that these oscillations may be related to tropical intraseasonal oscillations via large-scale eastward propagating atmospheric circulation wave-trains. The second pattern of intraseasonal variability, which captures in-phase variations of temperature, wind and sea level pressure, shows enhanced variability at timescales of , 35, , 60 and , 120 days. These oscillations are attributed to the Southern Annular Mode/Antarctic Oscillation (SAM/AAO) which shows enhanced variability at these timescales. We argue that intraseasonal oscillations of tropical climate and SAM/AAO are related to distinct patterns of climate variables measured at Neumayer.

Description: Emperor penguins (Aptenodytes forsteri Gray) are the only vertebrate species that breed during the Antarctic winter. From the beginning of the breeding season in April until fledging of the chicks in January, emperor penguins rely on the stability of sea (fast) ice. The International Union for Conservation of Nature (IUCN) has recently listed the species as ‘near threatened’ because the habitat of emperor penguins may deteriorate significantly over the coming years with the anticipated changes in sea ice conditions due to climate change. Since 2009, four emperor penguin colonies have been observed on ice shelves, as opposed to sea ice, during the breeding season (Fretwell et al. 2014). This striking change in their breeding behaviour was interpreted as an adaptation of emperor penguins to poor sea ice conditions. Here we report that a large part of the emperor penguin colony at Atka Bay (Dronning Maud Land, Antarctica) moved onto the ice shelf during the 2013 breeding season. This colony has been regularly observed since 1981 but has never before been seen breeding, incubating their eggs, brooding or crèching on the ice shelf. Our observations concur with a recent report, which documented that altered breeding behaviour in emperor penguins has occurred almost simultaneously across Antarctica (Fretwell et al. 2014). Interestingly, the sea ice at Atka Bay has been stable for three consecutive seasons and thus cannot have triggered this change in behaviour. Rather, we present evidence of increased snow accumulation that has greatly improved the accessibility of the ice shelves around Atka Bay, and we discuss additional meteorological factors and local topographical conditions that may have contributed to the shift in breeding location from sea ice onto an ice shelf.