Antarctic snow samples collected from the Wilkins Runway, c. 50 km inland from the Windmill Islands, East Antarctica, contain aeolian-derived diatoms. The diatom assemblage preserved is exclusively of marine origin. As diatoms are excellent indicators of source conditions, we are able to confirm that an unusual weather event, with anomalous north-westerly winds blowing at around 10 m s-1, resulted in the deposition of coastal marine species at the Wilkins Runway. The composition of the floral assemblage collected indicate that the parent water mass was from a coastal marine region undergoing typical Antarctic summer conditions with periods of both consolidated sea ice and open water. On inspection of available satellite imagery, these conditions were found upwind of the deposition site. This study provides a methodology for diatoms found within ice cores to be identified and the source region to be determined. It also provides evidence for a large-scale aeolian deposition of marine diatoms to an ice sheet, which may have implications for the interpretation of controversial marine diatoms found in sediments that have been used as evidence for the retreat of the East Antarctic Ice Sheet.

During the 2007–08 Spanish Antarctic campaign, two moorings of bottom pressure sensors were carried out over a ten week period. This paper presents the results of the tidal analysis from sea level records obtained at Deception and Livingston islands (South Shetland Islands, Antarctica). The main objective of this paper is to present a detailed study of the tidal characteristics at these two islands, for which statistical and harmonic analysis techniques are applied to the tidal records. A geodetic network was used to reference the pressure sensors. Geometric levelling, with an accuracy of 1 mm, allowed us to link the tidal marks with geodetic vertices located on Livingston and Deception islands. The amplitudes and phase lags obtained by harmonic analysis are compared to the harmonic constants of several coastal stations and co-tidal and co-range charts. Results show an evident influence of tides in the sea level signal, with a clear mixed semi-diurnal behaviour and a daily inequality between high and low waters. Measurements of salinity and temperature were made using electronic sensors. Results from this study showed that salinity and temperature were strongly influenced by tides. Seawater temperature varied in a manner that was consistent with the time series of residual bottom pressure.

Blue ice extent and its geographical distribution during the three years from December 1999–January 2003 have been mapped together with rock exposure areas for the entire Lambert-Amery glacial basin at an unprecedented level of spatial detail using Landsat ETM+ images. Various geometric and shape attributes for each blue ice patch have been derived. The total area of blue ice is estimated to be 20 422 km2, accounting for 1.48% of the glacial basin. We also found that the image texture information is helpful for distinguishing different types of blue ice: rough blue ice, smooth blue ice, and level blue ice. Rough blue ice areas are mostly associated with glacial dynamics and located in relatively low elevation regions, smooth blue ice areas are often related to nunataks and mountains, steep slopes and wind blows, and level blue ice areas are formed by melt-induced lakes in the margin of the ice shelf and melt-induced ponds on the ice shelf in low elevations. The elevation and surface slope properties of different types of blue ice area are characterized through regional topographical analysis with ICESat laser altimetry data. The effect of mountain height on the blue ice extent is also examined with local topographic profile analysis based on the ASTER global digital elevation model. The wide variation of the ratio of blue ice area length to mountain height indicates that the factors controlling the formation and extent of blue ice are more complicated than we previously thought.

It is well established that the reaction of HO2 with NO plays a central role in atmospheric chemistry, by way of OH/HO2 recycling and reduction of ozone depletion by HOx cycles in the stratosphere and through ozone production in the troposphere. Utilizing a photochemical box model, we investigate the impact of the recently observed HNO3 production channel (HO2+NO → HNO3) on NOx (NO + NO2), HOx (OH + HO2), HNO3, and O3 concentrations in the boundary layer at the South Pole, Antarctica. Our simulations exemplify decreases in peak O3, NO, NO2, and OH and an increase in HNO3. Also, mean OH is in better agreement with observations, while worsening the agreement with O3, HO2, and HNO3 concentrations observed at the South Pole. The reduced concentrations of NOx are consistent with expected decreases in atmospheric NOx lifetime as a result of increased sequestration of NOx into HNO3. Although we show that the inclusion of the novel HNO3 production channel brings better agreement of OH with field measurements, the modelled ozone and HNO3 are worsened, and the changes in NOx lifetime imply that snowpack NOx emissions and snowpack nitrate recycling must be re-evaluated.

A four-year set of vertical profiles of pressure, temperature and relative humidity derived from 1113 radiosoundings performed at Dome C (Antarctica) at 12h00 UT of each day, from late March 2005 to the end of March 2009, was examined by following a complex procedure for removing the most important lag errors and dry biases from the temperature and moisture data. The analysis provides evidence of annual cycles over the four years, characterizing the pressure and temperature conditions at the surface and at the various troposphere and low stratosphere levels, with maxima in summer and wide minima in winter for both parameters. Specific studies of the thermal parameters characterizing the ground layer and the tropopause region are also presented to describe their annual average variations. The analysis of moisture parameters indicates that absolute humidity varies regularly with season within the low troposphere, presenting well marked peaks in the summer months. Consequently, precipitable water was found to vary regularly during the year, from values of 0.2–0.4 mm in the winter to more than 0.6 mm in summer. The main year-to-year variations characterizing the monthly mean vertical profiles of pressure, temperature and moisture parameters are also described.

Tephra in glacial ice provide a method to obtain a depth vs chronology correlation within an ice core. Currently, core sections containing particulate must be sacrificially analysed to determine the nature of the particulate (e.g. aerosol, micrometeor, volcanic ash), and, in the case of volcanic ash, the event tied to the particle. Characterization through melting and chemical analysis precludes, de facto, its use for other purposes. A non-destructive technique to characterize particulates in ice cores prior to sectioning the samples, e.g. optical interrogation, would be useful, especially if chemical information specific to particular volcanic eruptions could be gleaned from such an analysis. We investigated the use of micro-Raman spectroscopy for this purpose. Spectra were obtained on samples of Antarctic blue ice tephra from different sources along with a reference ash sample of New Mexico Bandelier Tuff. Vitreous and crystalline particles in the samples were characterized. For vitreous material, a detailed analysis of the Raman-active vibrational bands of the glass structure was found to have the potential of being a unique identifier of the source of the glass, however, additional library development is needed for implementation.

We performed an artificial pool experiment in the Antarctic multi-year land-fast ice to examine and simulate the effect of sea ice melting on physical and biogeochemical components of the sea ice field. The input of snow and ice meltwater resulted in warmer, low salinity water at the surface of the pool and probably stratification of the less dense water. Current speed measurements also pointed to water stratification within the pool. Rapid phytoplankton growth in the pool resulted in drastic decreases in concentrations of dissolved inorganic carbon and nutrients (NO3- and Si(OH)4) in the surface waters of the pool, particularly depleted for NO3-. There was high correlation between variations of dissolved inorganic carbon and nutrient concentrations, but the apparent uptake ratios of these components deviated from that generally applied to marine phytoplankton. The sequence of changes in the physical and biogeochemical components of the pool water suggests that the onset of rapid phytoplankton growth was closely related to the water stratification, which provided stable conditions for phytoplankton bloom even though the supply of nutrients from under-ice water would have declined.

Antarctic subglacial lakes are studied for three main scientific reasons. First, they form an important component of the basal hydrological system which is known to affect the dynamics of the ice sheet. Second, they are amongst the most extreme viable habitats on Earth and third, if sediments exist on their floors, they may contain high-resolution records of ice sheet history. Here we present a new inventory of locations, dimensions and data sources for 379 subglacial lakes. Several major advances are responsible for the rise in the total number of lakes from the 145 known at the time of the last inventory in 2005. New radar datasets have been collected in previously unexplored regions of the ice sheet while digital data collection and processing techniques have allowed improvements to lake identification methods. Satellite measurements of ice surface elevation change caused by the movement of subglacial water have also been found to be widespread in Antarctica, often in places where radar data are absent. These advances have changed our appreciation of the Antarctic subglacial environment and have expanded our understanding of the behaviour of subglacial lakes.