Aeolian dust and diatoms at Roosevelt Island (Ross Sea, Antarctica) over the last two millennia reveal the local expression of climate changes and the history of the Ross Sea polynya
Serena Lagorio, Barbara Delmonte, Dieter Tetzner, Elisa Malinverno, Giovanni Baccolo, Barbara Stenni, Massimo Frezzotti, Valter Maggi, Nancy Bertler
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引用次数: 0
Abstract
Abstract. 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.
期刊介绍:
Climate of the Past (CP) is a not-for-profit international scientific journal dedicated to the publication and discussion of research articles, short communications, and review papers on the climate history of the Earth. CP covers all temporal scales of climate change and variability, from geological time through to multidecadal studies of the last century. Studies focusing mainly on present and future climate are not within scope.
The main subject areas are the following:
reconstructions of past climate based on instrumental and historical data as well as proxy data from marine and terrestrial (including ice) archives;
development and validation of new proxies, improvements of the precision and accuracy of proxy data;
theoretical and empirical studies of processes in and feedback mechanisms between all climate system components in relation to past climate change on all space scales and timescales;
simulation of past climate and model-based interpretation of palaeoclimate data for a better understanding of present and future climate variability and climate change.