Major explosive volcanic eruptions may significantly alter the global atmosphere for about 2–3 years. During that period, volcanic products (mainly H2SO4) with high residence time, stored in the stratosphere or, for shorter times, in the troposphere are gradually deposited onto polar ice caps. Antarctic snow may thus record acidic signals providing a history of past volcanic events. The high resolution sulphate concentration profile along a 197 m long ice core drilled at GV7 (Northern Victoria land) was obtained by Ion Chromatography on around 3500 discrete samples. The relatively high accumulation rate (241 ± 13 mm we yr −1) and the 5-cm sampling resolution allowed a preliminary counted age scale. The obtained stratigraphy covers roughly the last millennium and 24 major volcanic eruptions were identified, dated, and tentatively ascribed to a source volcano. The deposition flux of volcanic sulphate was calculated for each signature and the results were compared with data from other Antarctic ice cores at regional and continental scale. Our results show that the regional variability is of the same order of magnitude as the continental one.

While more and more studies are being conducted on carbonaceous fractions—organic carbon (OC) and elemental carbon (EC)—in urban areas, there are still too few studies about these species and their effects in polar areas due to their very low concentrations; further, studies in the literature report only data from intensive campaigns, limited in time. We present here for the first time EC–OC concentration long-time data records from the sea-level sampling site of Ny-Ålesund, in the High Arctic (5 years), and from Dome C, in the East Antarctic Plateau (1 year). Regarding the Arctic, the median (and the interquartile range (IQR)) mass concentrations for the years 2011–2015 are 352 (IQR 283–475) ng/m3 for OC and 4.8 (IQR: 4.6–17.4) ng/m3 for EC, which is responsible for only 3% of total carbon (TC). From both the concentration data sets and the variation of the average monthly concentrations, the influence of the Arctic haze on EC and OC concentrations is evident. Summer may be interesting owing to high concentration episodes mainly due to long-range transport (e.g., from wide wildfires in the Northern Hemisphere, as happened in 2015). The average ratio of EC/OC for the summer period is 0.05, ranging from 0.02 to 0.10, and indicates a clean environment with prevailing biogenic (or biomass burning) sources, as well as aged, highly oxidized aerosol from long-range transport. Contribution from ship emission is not evident, but this result may be due to the sampling time resolution. In Antarctica, a 1 year-around data set from December 2016 to February 2018 is shown, which does not present a clear seasonal trend. The OC median (and IQR) value is 78 (64–106) ng/m3; for EC, it is 0.9 (0.6–2.4) ng/m3, weighing for 3% on TC values. The EC/OC ratio mean value is 0.20, with a range of 0.06–0.35. Due to the low EC and OC concentrations in polar areas, correction for the blank is far more important than in campaigns carried out in other regions, largely affecting uncertainties in measured concentrations. Through the years, we have thus developed a new sampling strategy that is presented here for the first time: samplers were modified in order to collect a larger amount of particulates on a small surface, enhancing the capability of the analytical method since the thermo-optical analyzer is sensitive to carbonaceous aerosol areal density. Further, we have recently coupled such modified samplers with a sampling strategy that makes a more reliable blank correction of every single sample possible.

Abstract. Ice core dating is the first step for a correct interpretation of climatic and environmental changes. In this work, we release the dating of the uppermost 197 m of the 250 m deep GV7(B) ice core (drill site, 70∘41′ S, 158∘52′ E; 1950 m a.s.l. in Oates Land, East Antarctica) with a sub-annual resolution. Chemical records of NO3-, MSA (methanesulfonic acid), non-sea-salt SO42- (nssSO42-), sea-salt ions and water stable isotopes (δ18O) were studied as candidates for dating due to their seasonal pattern. Different procedures were tested but the nssSO42- record proved to be the most reliable on the short- and long-term scales, so it was chosen for annual layer counting along the whole ice core. The dating was constrained by using volcanic signatures from historically known events as tie points, thus providing an accurate age–depth relationship for the period 1179–2009 CE. The achievement of the complete age scale allowed us to calculate the annual mean accumulation rate throughout the analyzed 197 m of the core, yielding an annually resolved history of the snow accumulation on site in the last millennium. A small yet consistent rise in accumulation rate (Tr = 1.6, p<0.001) was found for the last 830 years starting around mid-18th century.

&lt;p&gt;Explosive volcanic eruptions are able to affect significantly the atmosphere for 2&amp;#8208;3 years. During this time, volcanic products (mainly H2SO4) with high residence &amp;#8232;time are stored in the stratosphere/troposphere, and eventually deposited onto polar ice caps; snow layers may thus record signals providing a history of past &amp;#8232;volcanic events. A high resolution sulphate concentration profile along a 197 m long ice core drilled at GV7 (Northern Victoria Land) was obtained by Ion Chromatography. The relatively high accumulation rate (241&amp;#177;13 mm we yr&lt;sup&gt;-1&lt;/sup&gt;) and the 5&amp;#8208;cm resolution allowed a preliminary counted age scale. The obtained stratigraphy covers roughly the last millennium and 24 major volcanic eruptions were identified, dated and &amp;#8232;ascribed to a source volcano. The deposition flux of volcanic sulfate was calculated and the results were compared with data from other Antarctic ice cores at regional and continental scale. Our results show that the regional variability is of the same order of magnitude &amp;#8232;of the continental scale.&lt;/p&gt;

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