Submit to Geosciences Review for Geosciences Propose a Special Issue

Journal Menu

Journal Browser

► Journal Browser

Climate Variability in Antarctica and the Southern Hemisphere over the Last Millennia

Print Special Issue Flyer
Special Issue Editors
Special Issue Information
Keywords
Related Special Issues
Published Papers

A special issue of Geosciences (ISSN 2076-3263). This special issue belongs to the section "Geophysics".

Deadline for manuscript submissions: closed (31 December 2019) | Viewed by 50914

Share This Special Issue

Special Issue Editors

Dr. Elizabeth Thomas

E-Mail Website
Guest Editor

British Antarctic Survey, Cambridge CB3 0ET, UK
Interests: ice cores; paleoclimate; Southern Hemisphere climate variability; sea ice; surface mass balance
Special Issues, Collections and Topics in MDPI journals

Dr. Claire Allen

E-Mail Website
Guest Editor

British Antarctic Survey, Cambridge CB3 0ET, UK
Interests: antarctic environments and the southern ocean; paleoceanography; high latitude climate variability; ocean-climate interactions; sea-ice; polar marine diatoms
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

This Special Issue of Geosciences aims to gather high quality original research articles and reviews on climate variability in Antarctica and the Southern Hemisphere over the last millennia.

We would like to invite members of the paleoclimate community to submit articles addressing how large-scale modes of atmospheric and oceanic variability, such as: the Southern Annual Mode (SAM), the Interdecadal Pacific Oscillation (IPO) and El Niño-Southern Oscillation (ENSO); influence the climate in Antarctica and the Southern Hemisphere on both a regional and hemispheric scale. We aim to improve our current understanding of the dominant modes of atmospheric and oceanic variability through evaluation of paleoclimate archives and modelling studies covering the past millennia. We particularly encourage data-model inter comparison and multi-proxy studies.

We encourage submissions based on the following topics:

Paleoclimate reconstructions from ice cores
Paleoclimate reconstructions from marine sediments
Paleoclimate reconstructions from terrestrial records (peat, lake sediments, etc.)
Southern Hemisphere modes of climate variability (e.g., SAM and westerly winds)
Past surface mass balance and glacial dynamics
Past sea ice conditions
Past ocean conditions (circulation, meltwater, productivity, etc.)
Low-high latitude connections
Modelled climate variability
Data–model intercomparison

We encourage authors to submit a short abstract, outlining the proposed research article, to the editors prior to submitting a full manuscript to ensure its fit with the objectives of this Special Issue.

Dr. Elizabeth Thomas
Dr. Claire Allen
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Geosciences is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

Antarctic Climate variability
Ice cores
Marine records
Terrestrial records
Climate dynamics
Paleoclimate reconstructions
Modes of variability (SAM, ENSO, IPO)
Ocean/ice-climate interactions
Climate- data intercomparisson
Southern Hemisphere Westerly Winds

Related Special Issues

Reconstitutions of Paleoenvironments and Paleoclimates using Stable Isotope Geochemistry in Geosciences (4 articles)
Climate and Environmental Change of Africa in Geosciences (2 articles)
Paleoclimate: Changes and Adaptation in Geosciences

Published Papers (9 papers)

Download All Papers

Research

Jump to: Review

19 pages, 7082 KiB

Open AccessArticle

Preliminary Evidence for the Role Played by South Westerly Wind Strength on the Marine Diatom Content of an Antarctic Peninsula Ice Core (1980–2010)

by Claire S. Allen, Elizabeth R. Thomas, Hilary Blagbrough, Dieter R. Tetzner, Richard A. Warren, Emily C. Ludlow and Thomas J. Bracegirdle

Geosciences 2020, 10(3), 87; https://doi.org/10.3390/geosciences10030087 - 26 Feb 2020

Cited by 6 | Viewed by 3932

Abstract

Winds in the Southern Ocean drive exchanges of heat and carbon dioxide between the ocean and atmosphere. Wind dynamics also explain the dominant patterns of both basal and surface melting of glaciers and ice shelves in the Amundsen and Bellingshausen Seas. Long records of past wind strength and atmospheric circulation are needed to assess the significance of these recent changes. Here we present evidence for a novel proxy of past south westerly wind (SWW) strength over the Amundsen and Bellingshausen Seas, based on diatoms preserved in an Antarctic Peninsula ice core. Ecological affinities of the identified diatom taxa indicate an almost exclusively marine assemblage, dominated by open ocean taxa from the Northern Antarctic Zone (NAZ). Back-trajectory analysis shows the routes of air masses reaching the ice core site and reveals that many trajectories involve contact with surface waters in the NAZ of the Amundsen and Bellingshausen Seas. Correlation analyses between ice core diatom abundance and various wind vectors yield positive and robust coefficients for the 1980–2010 period, with average annual SWW speeds exhibiting the strongest match. Collectively, the data presented here provide new evidence that diatoms preserved in an Antarctic Peninsula ice core offer genuine potential as a new proxy for SWW strength. Full article

(This article belongs to the Special Issue Climate Variability in Antarctica and the Southern Hemisphere over the Last Millennia)

► Show Figures

Figure 1

15 pages, 2564 KiB

Open AccessArticle

Volcanic Fluxes Over the Last Millennium as Recorded in the Gv7 Ice Core (Northern Victoria Land, Antarctica)

by Raffaello Nardin, Alessandra Amore, Silvia Becagli, Laura Caiazzo, Massimo Frezzotti, Mirko Severi, Barbara Stenni and Rita Traversi

Geosciences 2020, 10(1), 38; https://doi.org/10.3390/geosciences10010038 - 20 Jan 2020

Cited by 10 | Viewed by 5018

Abstract

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. Full article

(This article belongs to the Special Issue Climate Variability in Antarctica and the Southern Hemisphere over the Last Millennia)

► Show Figures

Figure 1

19 pages, 5529 KiB

Open AccessArticle

Southern Hemisphere Pressure Relationships during the 20th Century—Implications for Climate Reconstructions and Model Evaluation

by Logan Clark and Ryan Fogt

Geosciences 2019, 9(10), 413; https://doi.org/10.3390/geosciences9100413 - 24 Sep 2019

Cited by 6 | Viewed by 2655

Abstract

The relationship between Southern Hemisphere middle and high-latitude regions has made it possible to generate observationally-based Antarctic pressure reconstructions throughout the 20th century, even though routinely collected observations for this continent only began around 1957. While nearly all reconstructions inherently assume stability in these relationships through time and in the absence of direct observations, this stationarity constraint can be fully tested in a model setting. Seasonal pressure reconstructions based on the principal component regression (PCR) method spanning 1905–2013 are done entirely within the framework of the Community Atmospheric version 5 (CAM5) model in this study in order to evaluate this assumption, test the robustness of the PCR procedure for Antarctic pressure reconstructions and to evaluate the CAM5 model. Notably, the CAM5 reconstructions outperformed the observationally-based reconstruction in every season except the austral summer. Other tests indicate that relationships between Antarctic pressure and pressure across the Southern Hemisphere remain stable throughout the 20th century in CAM5. In contrast, 20th century reanalyses all display marked changes in mid-to-high latitude pressure relationships in the early 20th century. Overall, comparisons indicate both the CAM5 model and the pressure reconstructions evaluated here are reliable estimates of Antarctic pressure throughout the 20th century, with the largest differences between the two resulting from differences in the underlying reconstruction predictor networks and not from changes in the model experiments. Full article

(This article belongs to the Special Issue Climate Variability in Antarctica and the Southern Hemisphere over the Last Millennia)

► Show Figures

Figure 1

17 pages, 1593 KiB

Open AccessArticle

Warm Deep Water Variability During the Last Millennium in the CESM–LME: Pre-Industrial Scenario versus Late 20th Century Changes

by Marcos Tonelli, Fernanda Marcello, Bruno Ferrero and Ilana Wainer

Geosciences 2019, 9(8), 346; https://doi.org/10.3390/geosciences9080346 - 08 Aug 2019

Cited by 4 | Viewed by 3582

Abstract

Water transformation around Antarctica is recognized to significantly impact the climate. It is where the linkage between the upper and lower limbs of the Meridional Overturning Circulation (MOC) takes place by means of dense water formation, which may be affected by rapid climate change. Simulation results from the Community Earth System Model Last Millennium Ensemble (CESM–LME) are used to investigate the Weddell Sea Warm Deep Water (WDW) evolution during the Last Millennium (LM). The WDW is the primary heat source for the Weddell Sea (WS) and accounts for 71% of the Weddell Sea Bottom Water (WSBW), which is the regional variety of the Antarctic Bottom Water (AABW)—one of the densest water masses in the ocean bearing directly on the cold deep limb of the MOC. Earth System Models (ESMs) are known to misrepresent the deep layers of the ocean (below 2000 m), hence we aim at the upper component of the deep meridional overturning cell, i.e., the WDW. Salinity and temperature results from the CESM–LME from a transect crossing the WS are evaluated with the Optimum Multiparameter Analysis (OMP) water masses decomposition scheme. It is shown that, after a long–term cooling over the LM, a warming trend takes place at the surface waters in the WS during the 20th century, which is coherent with a global expression. The subsurface layers and. mainly. the WDW domain are subject to the same long–term cooling trend, which is decelerated after 1850 (instead of becoming warmer like the surface waters), probably due interactions with sea ice–insulated ambient waters. The evolution of this anomalous temperature pattern for the WS is clear throughout the three major LM climatic episodes: the Medieval Climate Anomaly (MCA), Little Ice Age (LIA) and late 20th century warming. Along with the continuous decline of WDW core temperatures, heat content in the water mass also decreases by 18.86%. OMP results indicate shoaling and shrinking of the WDW during the LM, with a ~6% decrease in its cross–sectional area. Although the AABW cannot be directly assessed from CESM–LME results, changes in the WDW structure and WS dynamics have the potential to influence the deep/bottom water formation processes and the global MOC. Full article

(This article belongs to the Special Issue Climate Variability in Antarctica and the Southern Hemisphere over the Last Millennia)

► Show Figures

Figure 1

18 pages, 1884 KiB

Open AccessArticle

South Atlantic Surface Boundary Current System during the Last Millennium in the CESM-LME: The Medieval Climate Anomaly and Little Ice Age

by Fernanda Marcello, Ilana Wainer, Peter R. Gent, Bette L. Otto-Bliesner and Esther C. Brady

Geosciences 2019, 9(7), 299; https://doi.org/10.3390/geosciences9070299 - 09 Jul 2019

Cited by 5 | Viewed by 3346

Abstract

Interocean waters that are carried northward through South Atlantic surface boundary currents get meridionally split between two large-scale systems when meeting the South American coast at the western subtropical portion of the basin. This distribution of the zonal flow along the coast is investigated during the Last Millennium, when natural forcing was key to establish climate variability. Of particular interest are the changes between the contrasting periods of the Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA). The investigation is conducted with the simulation results from the Community Earth System Model Last Millennium Ensemble (CESM-LME). It is found that the subtropical South Atlantic circulation pattern differs substantially between these natural climatic extremes, especially at the northern boundary of the subtropical gyre, where the westward-flowing southern branch of the South Equatorial Current (sSEC) bifurcates off the South American coast, originating the equatorward-flowing North Brazil Undercurrent (NBUC) and the poleward Brazil Current (BC). It is shown that during the MCA, a weaker anti-cyclonic subtropical gyre circulation took place (inferred from decreased southern sSEC and BC transports), while the equatorward transport of the Meridional Overturning Circulation return flow was increased (intensified northern sSEC and NBUC). The opposite scenario occurs during the LIA: a more vigorous subtropical gyre circulation with decreased northward transport. Full article

(This article belongs to the Special Issue Climate Variability in Antarctica and the Southern Hemisphere over the Last Millennia)

► Show Figures

Figure 1

17 pages, 3033 KiB

Open AccessEditor’s ChoiceArticle

A Validation of ERA5 Reanalysis Data in the Southern Antarctic Peninsula—Ellsworth Land Region, and Its Implications for Ice Core Studies

by Dieter Tetzner, Elizabeth Thomas and Claire Allen

Geosciences 2019, 9(7), 289; https://doi.org/10.3390/geosciences9070289 - 29 Jun 2019

Cited by 117 | Viewed by 9907

Abstract

Climate reanalyses provide key information to calibrate proxy records in regions with scarce direct observations. The climate reanalysis used to perform a proxy calibration should accurately reproduce the local climate variability. Here we present a regional scale evaluation of meteorological parameters using ERA-Interim and ERA5 reanalyses compared to in-situ observations from 13 automatic weather stations (AWS), located in the southern Antarctic Peninsula and Ellsworth Land, Antarctica. Both reanalyses seem to perform better in the escarpment area (>1000 m a.s.l) than on the coast. A significant improvement is observed in the performance of ERA5 over ERA-Interim. ERA5 is highly accurate, representing the magnitude and variability of near-surface air temperature and wind regimes. The higher spatial and temporal resolution provided by ERA5 reduces significantly the cold coastal biases identified in ERA-Interim and increases the accuracy representing the wind direction and wind speed in the escarpment. The slight underestimation in the wind speed obtained from the reanalyses could be attributed to an interplay of topographic factors and the effect of local wind regimes. Three sites in this region are highlighted for their potential for ice core studies. These sites are likely to provide accurate proxy calibrations for future palaeoclimatic reconstructions. Full article

(This article belongs to the Special Issue Climate Variability in Antarctica and the Southern Hemisphere over the Last Millennia)

► Show Figures

Figure 1

14 pages, 8013 KiB

Open AccessArticle

Regional Climate Change Recorded in Moss Oxygen and Carbon Isotopes from a Late Holocene Peat Archive in the Western Antarctic Peninsula

by Jonathan M. Stelling and Zicheng Yu

Geosciences 2019, 9(7), 282; https://doi.org/10.3390/geosciences9070282 - 26 Jun 2019

Cited by 3 | Viewed by 3271

Abstract

The Antarctic Peninsula (AP) climate is characterized by a high degree of variability, which poses a problem when attempting to put modern change in the context of natural variation. Therefore, novel methods are required to disentangle sometimes conflicting climate records from the region. In recent years, the development of Antarctic moss-cellulose isotopes as a proxy for summer terrestrial growing conditions has become more widespread, with the isotopes Δ¹³C and δ¹⁸O reflecting moss productivity and peatbank moisture conditions, respectively. Here, we used a combined Δ¹³C and δ¹⁸O isotope analysis of moss Chorisodontium aciphyllum cellulose from a peatbank located on Litchfield Island in the western AP to document changes in climate over the last 1700 years. High Δ¹³C values (>15‰) indicate warm and productive conditions on Litchfield Island from 1600 to 1350 cal yr BP (350 to 600 AD) and over the last 100 years. The δ¹⁸O record shows two distinct intervals of dry conditions at 1350–1000 cal yr BP (600–950 AD) and at 500–0 cal yr BP (1450–1950 AD). Our record indicates that terrestrial ecosystems in the AP have responded to regional climate driven by atmospheric circulation, such as the southern annular mode (SAM) and, to a lesser extent, changes in ocean circulation. Full article

(This article belongs to the Special Issue Climate Variability in Antarctica and the Southern Hemisphere over the Last Millennia)

► Show Figures

Figure 1

Review

Jump to: Research

33 pages, 7576 KiB

Open AccessEditor’s ChoiceReview

Antarctic Sea Ice Proxies from Marine and Ice Core Archives Suitable for Reconstructing Sea Ice over the Past 2000 Years

by Elizabeth R. Thomas, Claire S. Allen, Johan Etourneau, Amy C. F. King, Mirko Severi, V. Holly L. Winton, Juliane Mueller, Xavier Crosta and Victoria L. Peck

Geosciences 2019, 9(12), 506; https://doi.org/10.3390/geosciences9120506 - 04 Dec 2019

Cited by 37 | Viewed by 10046

Abstract

Dramatic changes in sea ice have been observed in both poles in recent decades. However, the observational period for sea ice is short, and the climate models tasked with predicting future change in sea ice struggle to capture the current Antarctic trends. Paleoclimate archives, from marine sedimentary records and coastal Antarctic ice cores, provide a means of understanding sea ice variability and its drivers over decadal to centennial timescales. In this study, we collate published records of Antarctic sea ice over the past 2000 years (2 ka). We evaluate the current proxies and explore the potential of combining marine and ice core records to produce multi-archive reconstructions. Despite identifying 92 sea ice reconstructions, the spatial and temporal resolution is only sufficient to reconstruct circum-Antarctic sea ice during the 20th century, not the full 2 ka. Our synthesis reveals a 90 year trend of increasing sea ice in the Ross Sea and declining sea ice in the Bellingshausen, comparable with observed trends since 1979. Reconstructions in the Weddell Sea, the Western Pacific and the Indian Ocean reveal small negative trends in sea ice during the 20th century (1900–1990), in contrast to the observed sea ice expansion in these regions since 1979. Full article

(This article belongs to the Special Issue Climate Variability in Antarctica and the Southern Hemisphere over the Last Millennia)

► Show Figures

Figure 1

29 pages, 2559 KiB

Open AccessReview

Back to the Future: Using Long-Term Observational and Paleo-Proxy Reconstructions to Improve Model Projections of Antarctic Climate

by Thomas J. Bracegirdle, Florence Colleoni, Nerilie J. Abram, Nancy A. N. Bertler, Daniel A. Dixon, Mark England, Vincent Favier, Chris J. Fogwill, John C. Fyfe, Ian Goodwin, Hugues Goosse, Will Hobbs, Julie M. Jones, Elizabeth D. Keller, Alia L. Khan, Steven J. Phipps, Marilyn N. Raphael, Joellen Russell, Louise Sime, Elizabeth R. Thomas, Michiel R. van den Broeke and Ilana Wainer Show full author list Hide full author list

Geosciences 2019, 9(6), 255; https://doi.org/10.3390/geosciences9060255 - 07 Jun 2019

Cited by 26 | Viewed by 8090

Abstract

Quantitative estimates of future Antarctic climate change are derived from numerical global climate models. Evaluation of the reliability of climate model projections involves many lines of evidence on past performance combined with knowledge of the processes that need to be represented. Routine model evaluation is mainly based on the modern observational period, which started with the establishment of a network of Antarctic weather stations in 1957/58. This period is too short to evaluate many fundamental aspects of the Antarctic and Southern Ocean climate system, such as decadal-to-century time-scale climate variability and trends. To help address this gap, we present a new evaluation of potential ways in which long-term observational and paleo-proxy reconstructions may be used, with a particular focus on improving projections. A wide range of data sources and time periods is included, ranging from ship observations of the early 20^th century to ice core records spanning hundreds to hundreds of thousands of years to sediment records dating back 34 million years. We conclude that paleo-proxy records and long-term observational datasets are an underused resource in terms of strategies for improving Antarctic climate projections for the 21^st century and beyond. We identify priorities and suggest next steps to addressing this. Full article

(This article belongs to the Special Issue Climate Variability in Antarctica and the Southern Hemisphere over the Last Millennia)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Climate Variability in Antarctica and the Southern Hemisphere over the Last Millennia

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Related Special Issues

Published Papers (9 papers)

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI