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Using data from three automatic weather stations (LGB69, Eagle and Dome A) from distinctly different climatological zones along the CHINARE (Chinese National Antarctic Research Expedition) traverse route from Zhongshan Station to Dome A, we investigated the characteristics of meteorological conditions and subsurface heat conduction. Spatial analysis indicated decreasing trends in air temperature, relative humidity and wind speed from the coastal katabatic wind zone to the inland plateau region, and air temperatures clearly showed a strong daily variability in winter, suggesting the effect from the fluctuation in the Antarctic atmospheric system. We also analyzed the optimal response time of the 1 and 3 m depth snow temperatures to the 0.1 m depth snow temperature for each site under clear/overcast and day/night situations. This showed an important enhancement to the heat transfer from shortwave radiation penetration. Using an iterative optimization method, we estimated the subsurface heat conduction variations along the transect. This was ~3–5 W m–2. Multiple maxima in daily mean subsurface fluxes were found in winter, with a typical value above 2 W m–2, while a single minimum value under –2 W m–2 was found in summer. On an annual scale, a larger mean loss of subsurface heat conduction was observed in the inland plateau compared to in the coastal katabatic area. Finally, we discussed the possible influences of turbulent and radiant transport on the vertical heat response and confirmed the wind enhancement on the growth of thermal conductivity. This preliminary study provides a brief perspective and an important reference for studying subsurface heat conduction in inland areas of Antarctica. [ABSTRACT FROM AUTHOR]

During the second half of the twentieth century, the West Antarctic Ice Sheet (WAIS) has undergone significant warming at more than twice the global mean and thus is regarded as one of the most rapidly warming regions on Earth. However, a reversal of this trend was observed in the 1990s, resulting in regional cooling. In particular, during 1999–2018, the observed annual average surface air temperature had decreased at a statistically significant rate, with the strongest cooling in austral spring. The spring cooling correlates significantly with the second leading modes (EOF2) derived from empirical orthogonal function (EOF) analysis on the sea level pressure over Antarctica during 1999–2018, associated with the negative phase of the interdecadal Pacific oscillation with an average of cooling of central and eastern tropical Pacific surface sea temperature (SST) anomalies. The EOF2 results in the enhanced cold southerly winds on the continental WAIS through the cyclonic conditions over the Amundsen Sea region and a blocking high in the Drake Passage and northern Antarctic Peninsula, causing the WAIS cooling trend. [ABSTRACT FROM AUTHOR]

Landfast ice (LFI) plays a crucial role for both the climate and the ecosystem of the Antarctic coastal regions. We investigate the snow and LFI mass balance in Prydz Bay using observations from 11 sea ice mass balance buoys (IMBs). The buoys were deployed offshore from the Chinese Zhongshan Station (ZS) and Australian Davis Station (DS), with the measurements covering the ice seasons of 2009–2010, 2013–2016, and 2018. The observed annual maximum ice thickness and snow depth were 1.59 ± 0.17 and 0.11–0.76 m off ZS and 1.64 ± 0.08 and 0.11–0.38 m off DS, respectively. Early in the ice growth season (May–September), the LFI basal growth rate near DS (0.6 ± 0.2 cmd-1) was larger than that around ZS (0.5 ± 0.2 cmd-1). This is attributed to cooler air temperature (AT) and lower oceanic heat flux at that time in the DS region. Air temperature anomalies were more important in regulating the LFI growth rate at that time because of thinner sea ice having a weaker thermal inertia relative to thick ice in later seasons. Interannual and local spatial variabilities for the seasonality of LFI mass balance identified at ZS are larger than at DS due to local differences in topography and katabatic wind regime. Snow ice contributed up to 27 % of the LFI total ice thickness at the offshore site close to ground icebergs off ZS because of the substantial snow accumulation. Offshore from ZS, the supercooled water was observed at the sites close to the Dålk Glacier from July to October, which reduced the oceanic heat flux and promoted the LFI growth. During late austral spring and summer, the increased oceanic heat flux led to a reduction of LFI growth at all investigated sites. The variability of LFI properties across the study domain prevailed at interannual timescales, over any trend during the recent decades. Based on the results derived from this study, we argue that an increased understanding of snow (on LFI) processes, local atmospheric and oceanic conditions, as well as coastal morphology and bathymetry, are required to improve the Antarctic LFI modeling. [ABSTRACT FROM AUTHOR]

Landfast ice (LFI) plays an important role in the climate and ecosystem of the Antarctic coastal regions. We investigate the LFI snow and ice mass balance in Prydz Bay using data collected by 11 sea ice mass balance buoys (IMBs). The observations were distributed offshore from the Chinese Zhongshan Station (ZS) and Australian Davis Station (DS), and covered 2009-2010, 2013-2016 and 2018 ice seasons. The observed LFI annual maximum ice thickness and snow depth were 1.59±0.17 and 0.11-0.76 m off ZS and 1.64±0.08 and 0.11-0.38 m off DS, respectively. Early in the ice growth season, the LFI basal growth rate near DS (0.6±0.2 cm d-1) exceeds that around ZS (0.5±0.2 cm d-1). This is attributed to cooler air temperature and lower oceanic heat flux at that time in the DS region. Snow ice contributes up to 27% of the LFI total ice thickness at the offshore site close to ground icebergs off ZS because of the substantial snow accumulation. Larger interannual and local spatial variabilities for the seasonality of LFI mass balance identified at ZS than at DS are due to local differences in topography and katabatic wind regime. Air temperature anomalies are more important in regulating the LFI growth rate in the early ice growth season because of thinner sea ice relative to later seasons due to the weak thermal inertia of thin ice. Offshore from ZS, the year-round supercooled water from the nearby Dålk Glacier reduces the oceanic heat flux, promoting the LFI growth at the associated sites throughout the entire ice growth season. During late austral spring and summer, we found the increased oceanic heat flux leading to a reduction of LFI growth at all investigated sites. At interannual timescale, we found that variability of LFI properties across the study domain prevailed, over any trend during the recent decades. We argue that an increased understanding of local atmospheric and oceanic conditions, as well as surface morphology and coastal bathymetry, are required to improve the Antarctic LFI modelling at local and regional scale. [ABSTRACT FROM AUTHOR]

The ice-ocean boundary layer parameters are one of the main drivers of sea ice mass balance in the Polar Regions. To investigate the oceanic contribution to the landfast ice evolution, an integrated ocean observation system, including Acoustic Doppler Velocimeter, COMPACT-CTD, and Sea Ice Mass Balance Array, was deployed near Zhongshan Station in Prydz Bay, East Antarctica. The minute-resolution of ocean temperature, salinity, density, current, and heat flux from 16 to 23 April, 2021 were obtained and analysed. The results showed that ocean temperature experienced a jump increase, from - 1.59±0.03°C during 16-19 April to -1.47±0.07°C during 20-23 April, which may relate to the tide transform from semi-diurnal to diurnal. Ocean salinity and density showed a gradual trend increasing by 0.013 psu day-1 and 0.009 kg m-3 day-1, respectively, related to the salt rejection of ice bottom freezing. The mean ocean velocity was 3.13±1.63 cm s-1 and 34% of the current directions accounted to the northwest. Oceanic heat flux was estimated by the bulk parameterization method and residual energy method, which were 32.26±18.07 W m-2 and 34.95±17.52 W m-2, averaged for the study period respectively. Oceanic heat flux showed a large increase during 20-23 April, which shut down ice growth and resulted in 2 cm melting at the ice bottom. The high frequency of ocean observations allows us to deeply investigate diurnal changes of oceanic regimes and understand their influences on sea ice evolution. [ABSTRACT FROM AUTHOR]

This paper introduces a unique multiyear dataset and the monitoring capability of the PANDA automatic weather station network which includes eleven automatic weather stations (AWS) across Prydz Bay-Amery Ice Shelf-dome area from the coast to the summit of the East Antarctica ice sheet. The ~1460 km transect from Zhongshan to Panda S station follows roughly along ~77° E longitude and covers all geographic and climatic units of East Antarctica. Initial inland observation, near the coast, started in the 1996/1997 austral summer. All AWSs in this network measure air temperature, relative humidity, air pressure, wind speed and wind direction at 1-hour intervals, and some of them can also measure firn temperature and shortwave/longwave radiation. Data are relayed in near real-time via the ARGOS system. Data quality is generally very reliable and the data have been used widely. In this paper, we firstly present a detailed overview of the AWSs, including the sensor characteristics, installation procedure, data quality control protocol, and the basic analysis of each variable. We then give an example of a short-term atmospheric event that shows the monitoring capacity of the network. This dataset, which is publicly available, is planned to be updated on a near-real time and should be valuable for climate change estimation, extreme weather events diagnosis, data assimilation, weather forecasting, etc. The dataset is available at https://doi.org/10.11888/Atmos.tpdc.272721 (Ding et al., 2022). [ABSTRACT FROM AUTHOR]