Spatial and temporal distribution of environmental markers from coastal to plateau areas in Antarctica by firn core chemical analysis

The chemical analysis of shallow firn cores sampled in coastal and plateau areas in Northern Victoria Land and along a transect from Talos Dome to Dome C (East Antarctica, Pacific Ocean sector) allowed a global view of spatial and temporal changes in chemical composition of snow depositions over the last 100 years. Variations in concentration of primary (sea spray) and secondary (biogenic emission, atmospheric inputs) source markers were observed and discussed as a function of distance from the sea and altitude. In the stations characterized by relatively high snow accumulation rates, the sub-sampling resolution was sufficient to obtain a stratigraphic dating by using the periodical variations of seasonal markers. In these stations, a subdivision in "summer" and "winter" samples was carried out in order to study the seasonal changes of the contributions of the measured compounds to the snow composition as elevation and distance from the sea increase. Some evidence of post-depositional effects which are able to change the original deposition of chloride and nitrate, was observed at stations with low accumulation rates. The reliability of the depth/concentration profile of these substances for reconstructing past deposition was also discussed

Chemical and isotopic snow variability in East Antarctica along the 2001/02 ITASE traverse

As part of the International Trans-Antarctic Scientific Expedition (ITASE) project, a traverse was carried out from November 2001 to January 2002 through Terre Adelie, George V Land, Oates Land and northern Victoria Land, for a total length of about 1875 km. The research goal is to determine the latitudinal and longitudinal variability of physical, chemical and isotopic parameters along three transects: one west\u2013east transect (WE), following the 2150m contour line (about 400km inland of the Adelie, George V and Oates coasts), and two north\u2013south transects (inland Terre Adelie and Oates Coast\u2013Talos Dome\u2013Victoria Land). The intersection between the WE and Oates Coast\u2013Victoria Land transects is in the Talos Dome area. Along the traverse, eight 2m deep snow pits were dug and sampled with a 2.5cm depth resolution. For spatial variability, 1m deep integrated samples were collected every 5 km (363 sampling sites). In the snow-pit stratigraphy, pronounced annual cycles, with summer maxima, were observed for nssSO42\u2013, MSA, NO3\u2013 and H2O2. The seasonality of these chemical trace species was used in combination with stable-isotope stratigraphy to derive reliable and temporally representative snow-accumulation rates. The study of chemical, isotopic and accumulation-rate variability allowed the identification of a distribution pattern which is controlled not only by altitude and distance from the sea, but also by the complex circulation of air masses in the study area. In particular, although the Talos Dome area is almost equidistant from the Southern Ocean and the Ross Sea, local atmospheric circulation is such that the area is strongly affected only by the Ross Sea. Moreover, we observed a decrease in concentration of aerosol components in the central portion of the WE transect and in the southern portion of the Talos Dome transect; this decrease was linked to the higher stability of atmospheric pressure due to the channelling of katabatic winds

Chemical and isotopic snow variability in East Antarctica along the 2001/02 ITASE traverse

As part of the International Trans-Antarctic Scientific Expedition (ITASE) project, a traverse was carried out from November 2001 to January 2002 through Terre Adélie, George V Land, Oates Land and northern Victoria Land, for a total length of about 1875 km. The research goal is to determine the latitudinal and longitudinal variability of physical, chemical and isotopic parameters along three transects: one west-east transect (WE), following the 2150 m contour line (about 400 km inland of the Adélie, George V and Oates coasts), and two north-south transects (inland Terre Adélie and Oates Coast-Talos Dome-Victoria Land). The intersection between the WE and Oates Coast-Victoria Land transects is in the Talos Dome area. Along the traverse, eight 2 m deep snow pits were dug and sampled with a 2.5 cm depth resolution. For spatial variability, 1 m deep integrated samples were collected every 5 km (363 sampling sites). In the snow-pit stratigraphy, pronounced annual cycles, with summer maxima, were observed for nssSO 42-, MSA, NO 3- and H 2O 2. The seasonality of these chemical trace species was used in combination with stable-isotope stratigraphy to derive reliable and temporally representative snow-accumulation rates. The study of chemical, isotopic and accumulation-rate variability allowed the identification of a distribution pattern which is controlled not only by altitude and distance from the sea, but also by the complex circulation of air masses in the study area. In particular, although the Talos Dome area is almost equidistant from the Southern Ocean and the Ross Sea, local atmospheric circulation is such that the area is strongly affected only by the Ross Sea. Moreover, we observed a decrease in concentration of aerosol components in the central portion of the WE transect and in the southern portion of the Talos Dome transect; this decrease was linked to the higher stability of atmospheric pressure due to the channelling of katabatic winds