Characteristics of inertia-gravity waves (IGWs) at high latitude in Antarctica are investigated using radiosondes launched daily at Jang Bogo Station (74°37 0 S, 164°13 0 E), a new Antarctic station that has been operating since 2014, in the troposphere (z = 2-7 km) and lower stratosphere (z = 15-22 km) for 25 months (December 2014 to December 2016). The vertical propagation of IGWs exhibits strong seasonal variations in the stratosphere, with an enhancement (reduction) in downward (upward)-propagating IGWs from May to mid-October. In the troposphere, both upward-and downward-propagating IGWs have similar occurrence rates without seasonal variations. The intrinsic phase velocity of IGWs mostly direct to the west (isotropic), while the ground-relative phase and group velocities are dominant in the east and southeast (northeast), respectively, in the stratosphere (troposphere). The intrinsic frequency, vertical wavelength, and horizontal wavelength of IGWs averaged in the troposphere (stratosphere) are 3.57f (1.93f; where f is the Coriolis parameter), 1.48 (1.48) km, and 63.06 (221.81) km, respectively. The wave energy in the stratosphere has clear seasonal variations with large values in autumn and spring, while that in the troposphere is smaller without obvious seasonal variations. Zonal and meridional momentum fluxes averaged in the stratosphere (troposphere) are À0.008 (À0.0018) and À0.0005 (0.001) m 2 /s 2 , respectively. The momentum flux of downward-propagating IGWs in the stratosphere is mostly positive in both zonal and meridional directions, whereas the directional preference is not obvious in the troposphere. In Part 2, sources of the observed IGWs in the troposphere and stratosphere will be examined.

Reconstruction of the long-term surface temperature history in Antarctica is important for a better understanding of human-induced climate changes, especially since the Industrial Revolution. We present here a surface temperature history spanning the last century at Styx Glacier, located on the eastern coast of northern Victoria Land, which is reconstructed using borehole logging data. Our results indicate that surface temperatures in the 20th century were 1.7 ± 0.4°C higher than the long term averages over 1600-1900 Common Era, indicating regional warming over the eastern coast of northern Victoria Land. However, we found no evidence for significant warming across the northern Victoria Land since the mid-20th century. A global reanalysis as well as the reconstruction of proxy records demonstrate that the climate in this region was more affected by changes in the Southern Hemisphere Annular Mode than in the Amundsen-Bellingshausen Sea Low.Plain Language Summary The western coast of the Ross Sea, northern Victoria Land, is one of several regions around the world where the temperature history is highly uncertain. Here we provide a temperature reconstruction using borehole logging data from Styx Glacier. The reconstructed temperature history indicates that the surface temperature at Styx Glacier in the 20th century is higher than in previous centuries, although there is no significant trend since~1950s. The lack of recent warming trend off the western Ross Sea is in contrast to the warming in the Antarctic Peninsula and West Antarctica.

We report on the first summer of high‐sensitivity radon measurements from a two‐filter detector at Jang Bogo Station (Terra Nova Bay) and contrast them with simultaneous observations at King Sejong Station (King George Island). King Sejong radon concentrations were characteristic of a marine baseline station (0.02–0.3 Bq m−3), whereas Jang Bogo values were highly variable (0.06–5.2 Bq m−3), mainly due to emissions from exposed coastal ground (estimated mean flux 0.09–0.11 atoms cm−2 s−1) and shallow atmospheric mixing depths. For wind speeds of ≤3.5 m s−1 the influence of local radon emissions became increasingly more prominent at both sites. A cluster analysis of back trajectories from King Sejong (62°S) revealed a fairly even distribution between air masses that had passed recently over South America, the Southern Ocean, and Antarctica, whereas at Jang Bogo (75°S) 80% of events had recently passed over the Ross Ice Shelf and West Antarctica, 12% were synoptically forced over Cape Adare, and 8% were associated with subsidence over the Antarctic interior and katabatic flow to the station. When cross‐checked against radon concentrations, only half of the back trajectories ending at Jang Bogo that had indicated distant contact with nonpolar southern hemisphere continents within the past 10 days showed actual signs of terrestrial influence. A simple‐to‐implement technique based on high‐pass filtered absolute humidity is developed to distinguish between predominantly katabatic, oceanic, and near‐coastal air masses for characterization of trace gas and aerosol measurements at coastal East Antarctic sites.

Investigating warming in West Antarctica is important to understand and predict mass balance changes of the ice sheet. However, clear understanding of the extent and rate of warming across West Antarctica has been limited by the lack of ground‐based meteorological measurements. An automatic weather station was set up at Lindsey Islands, the Amundsen Sea of West Antarctica, in 2008, and operated for about 7 years. The measured variables showed high interannual variability, particularly in winter seasons. The longitudinal shift of the center of the Amundsen Sea Low contributed to the large variability and resulted in much lower temperatures at the site, especially in winter seasons, through cold advection from the south. The measured data showed good agreement with ERA‐Interim and ERA5 reanalysis data, though there was a large negative bias in wind speed. The ERA‐Interim reanalysis data showed no significant trends in seasonal averaged temperature from 1980 to 2014, but significant trends were shown in pressure and wind speed in autumn (p < 0.05), even though the interpretation of the trend requires caution. The seasonal correlation coefficients of monthly averaged temperature (T) and pressure (P) between the study site and three neighboring automatic weather station sites in the coastal area were >0.8 for T and >0.92 for P and up to 0.76 for P and 0.72 for T at an inland site.