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The pattern of atmospheric and climate changes recorded by coastal Antarctic ice core sites, and the processes they illustrate, highlight the importance of multiproxy studies on ice cores drilled from such peripheral areas, where regional to local-scale processes can be documented. Here, we present a 2000 year long record of aeolian mineral dust and diatoms windblown to the Roosevelt Island obtained from the RICE (Roosevelt Island Climate Evolution project) ice core. Mineral dust and diatoms are highly complementary at RICE since they are related to the large-scale South Pacific atmospheric circulation regime, carrying dust-rich air masses that travelled above the marine boundary layer, and local oceanic aerosol transport by low-level marine air masses, respectively. The 550–1470 CE period is characterized by enhanced mineral dust transport originating from the Southern Hemisphere continents, reduced sea-ice extent in the Eastern Ross and Amundsen Seas, and more frequent penetration of humid air masses responsible for the relative increase in snow accumulation. Around 1300 CE, in particular, in concomitance with marked El Niño-like conditions, the Ross Sea dipole reaches its maximum expression. After 1470 CE, relatively lower dust and snow deposition at RICE suggests an increase in pack ice. This period is characterized by episodes of unprecedented peaks of aeolian diatom deposition, indicating a rapid reorganization of atmospheric circulation linked to the eastward enlargement of the Ross Sea polynya, likely culminating with the opening of the proposed Roosevelt Island polynya, and to an increased influence of low-level marine air masses to the site during the Little Ice Age. [ABSTRACT FROM AUTHOR]

Abstract. High-resolution, well-dated climate archives provide anopportunity to investigate the dynamic interactions of climate patternsrelevant for future projections. Here, we present data from a new, annuallydated ice core record from the eastern Ross Sea, named the Roosevelt IslandClimate Evolution (RICE) ice core. Comparison of this record with climatereanalysis data for the 1979–2012 interval shows that RICE reliably capturestemperature and snow precipitation variability in the region. Trends over thepast 2700 years in RICE are shown to be distinct from those in WestAntarctica and the western Ross Sea captured by other ice cores. For most ofthis interval, the eastern Ross Sea was warming (or showing isotopicenrichment for other reasons), with increased snow accumulation and perhapsdecreased sea ice concentration. However, West Antarctica cooled and thewestern Ross Sea showed no significant isotope temperature trend. Thispattern here is referred to as the Ross Sea Dipole. Notably, during theLittle Ice Age, West Antarctica and the western Ross Sea experienced colderthan average temperatures, while the eastern Ross Sea underwent a period ofwarming or increased isotopic enrichment. From the 17th century onwards, thisdipole relationship changed. All three regions show current warming, withsnow accumulation declining in West Antarctica and the eastern Ross Sea butincreasing in the western Ross Sea. We interpret this pattern as reflectingan increase in sea ice in the eastern Ross Sea with perhaps the establishmentof a modern Roosevelt Island polynya as a local moisture source for RICE.

Abstract. High-resolution, well-dated climate archives provide an opportunity to investigate the dynamic interactions of climate patterns relevant for future projections. Here, we present data from a new, annually-dated ice core record from the eastern Ross Sea. Comparison of the Roosevelt Island Climate Evolution (RICE) ice core records with climate reanalysis data for the 1979–2012 calibration period shows that RICE records reliably capture temperature and snow precipitation variability of the region. RICE is compared with data from West Antarctica (West Antarctic Ice Sheet Divide Ice Core) and the western (Talos Dome) and eastern (Siple Dome) Ross Sea. For most of the past 2,700 years, the eastern Ross Sea was warming with perhaps increased snow accumulation and decreased sea ice extent. However, West Antarctica cooled whereas the western Ross Sea showed no significant temperature trend. From the 17th Century onwards, this relationship changes. All three regions now show signs of warming, with snow accumulation declining in West Antarctica and the eastern Ross Sea, but increasing in the western Ross Sea. Analysis of decadal to centennial-scale climate variability superimposed on the longer term trend reveal that periods characterised by opposing temperature trends between the Eastern and Western Ross Sea have occurred since the 3rd Century but are masked by longer-term trends. This pattern here is referred to as the Ross Sea Dipole, caused by a sensitive response of the region to dynamic interactions of the Southern Annual Mode and tropical forcings.

The article discusses the use of tritium (3 H) and cesium (137 Cs) as temporal markers in ice cores extracted from temperate glaciers. We present a complete tritium profile for a 46 m ice core drilled from the Adamello Glacier, a temperate glacier in the Italian Alps, and compare it to the 137 Cs profile from the same ice core. Our analysis reveals tritium contamination between 19 and 32 m of depth, which can be attributed to the global radioactive fallout caused by atmospheric nuclear-bomb testing that took place in the 1950s and 1960s. Results show that the radioactive peak associated with 1963 does not occur at the same depth for both 3 H and 137 Cs; instead, the tritium peak is 1.5 m above the cesium one. Our hypothesis is that this misalignment is caused by meltwater-induced post-depositional processes that affect 137 Cs, which is more sensitive to percolation than 3 H. The total inventory of 137 Cs in this ice core is also among the lowest ever reported, providing additional evidence that the presence of meltwater has affected the distribution of this radionuclide within the ice. In contrast, the total tritium inventory is comparable to what is reported in the literature, making it a more reliable temporal marker for temperate glaciers. [ABSTRACT FROM AUTHOR]

The article discusses the use of ³H and 137Cs as temporal markers in ice cores extracted from temperate glaciers. We present a complete tritium (³H) profile for a 46 m ice core drilled from Adamello glacier, a temperate glacier in the Italian Alps, and compare it to 137Cs profile from the same ice core. Our analysis reveals contamination of tritium between 19 and 32m of depth, which can be attributed to the worldwide radioactive contamination caused by atmospheric nuclear bomb testing in the 1950s and 1960s. Results show that the radioactive peak associated with 1963 is not coincident for ³H and 137Cs, but the ³H peak occurs 1.5m above the 137Cs one. This misalignment is caused by meltwater-induced postdepositional processes that affect 137Cs, which is more sensitive to percolation than ³H. The total inventory of 137Cs in this ice core is also among the lowest ever reported, providing additional evidence that meltwater disturbed its distribution into the ice. On the contrary, the total tritium inventory is comparable to what is reported in literature, making it a more reliable temporal marker for temperate glaciers. [ABSTRACT FROM AUTHOR]

As part of the "East Antarctic International Ice Sheet Traverse" (EAIIST) project, surface snow and snow pit samples were collected along a traverse from Dome C toward the geographic South Pole during the 2019–2020 Antarctic campaign. Results on spatial distribution of major ions are here reported to understand deposition and post deposition processes in sites with very low snow accumulation rate in the East Antarctic Plateau where megadune and wind crust areas are present. The volcanic signature of Pinatubo eruption (occurred in 1991) was clearly visible in the non-sea salt SO42− stratigraphy from two snow pits (AGO-5 and PALEO) allowing the determination of annual accumulation rates that revealed to be 25.7 and 22.6 mm of water equivalent/year, respectively at the two sites. Moreover, a decreasing trend in accumulation rate as the distance from the Indian Ocean increases was detected. Mineral dust concentration and size show presence of a criptotephra layer in AGO5 and PALEO stratigraphies which is stratigraphically compatible with the deposition of volcanic ash related to the Puyehue-Cordón Caulle explosive eruption occurred in June 2011. The ssNa+ fraction, accounting for the 92.5 % of the total Na+, is preserved stably in the snow layers and was chosen as marker of sea spray deposition. Despite the very low accumulation rate in this area, the main deposition process of sea spray aerosol is the wet deposition. Conversely, both biogenic and crustal nssSO42− are dry deposited, the total flux of nssSO42− resulted to be constant in the Antarctic plateau, but the biogenic to crustal ratio increases as distance from Dome C increases. The presence and quantification (by nssCa2+) of a dry deposited crustal source, as the biogenic one, sheds light on the interpretation of nssSO42− biogenic stratigraphy during glacial and interglacial time in Antarctic ice cores. NssCl− represent the fraction of Cl− deposited as HCl and arises from the exchange reactions between chloride in the sea salt aerosol and acidic species such as H2SO4 and HNO3 that occurs both into the atmosphere (in this case HCl is deposited by wet deposition) and into the snow (at the expenses of NaCl or MgCl2 deposited as sea salt aerosol). The latter process could be particularly efficient in sites affected by wind crust formation, probably because of a longer exposure time of the snow layers to the atmosphere favouring the HCl volatilization. Another important marker in ice core is HNO3, that in the considered sites is found at very high concentration in the most superficial 3 cm of snow due to the uptake by superficial snow and possibly concentration effects from the layers beneath, but it is reversibly deposited. The depth of the active layer for HNO3 reemission was calculated and it spans from 22 cm to 12 cm; in addition, the concentration preserved in the snow decreases as the accumulation rate decreases, but wind scouring increases the efficiency of re-emission processes in the active layer. The knowledge and quantification of all the above reported processes will allow the interpretation of the ice core stratigraphies in low accumulation site likely hopefully recording, at selected sites, the climate history of more than one million years ago. [ABSTRACT FROM AUTHOR]