scholarly journals Dust and associated trace element fluxes in a firn core from the coastal East Antarctica and its linkages with the Southern Hemisphere climate variability over the last ~ 50 yr

2013 ◽  
Vol 9 (2) ◽  
pp. 1841-1867 ◽  
Author(s):  
C. M. Laluraj ◽  
M. Thamban ◽  
K. Satheesan
Keyword(s):  
Climate Variability ◽  
Trace Element ◽  
Southern Annular Mode ◽  
East Antarctica ◽  
Dust Deposition ◽  
Back Trajectories ◽  
North West ◽  
Element Fluxes ◽  
Dust Flux ◽  
Firn Core

Abstract. High-resolution records of dust and trace element fluxes were studied in a firn core from the coastal Dronning Maud Land (cDML) in East Antarctica to identify the influence of climate variability on accumulation of these components over the past ~ 50 yr. A doubling of dust deposition was observed since 1985, coinciding with a shift in the Southern Annular Mode (SAM) index to positive values and associated increase in the wind speed. Back-trajectories showed that an increase in dust deposition is associated with the air parcels originating from north-west of the site, possibly indicating its origin from the Patagonian region. Our results suggest that while multiple processes could have influenced the increased dust formation, shift in SAM had a dominant influence on its transport. It is observed that since the 1985s the strength of easterlies increased significantly over the cDML region, which could sink air and dust material to the region that were brought by the westerlies through mass compensation. The correlation between the dust flux and δ18O records further suggest that enhanced dust flux in the firn core occurred during periods of colder atmospheric temperature, which reduced the moisture content and increased dust fall. Interestingly, the timing and amplitude of the insoluble dust peaks matched remarkably well with the fluxes of Ba, Cr, Cu, and Zn confirming that dust was the main carrier/source of atmospheric trace elements to East Antarctica during the recent past.

Source composition and seasonal variation of particulate trace element fluxes in Prydz Bay, East Antarctica

Chemosphere ◽  
2016 ◽  
Vol 147 ◽  
pp. 318-327 ◽  
Author(s):  
Wei-Ping Sun ◽  
Zheng-Bing Han ◽  
Chuan-Yu Hu ◽  
Jian-Ming Pan
Keyword(s):  
Seasonal Variation ◽  
Trace Element ◽  
East Antarctica ◽  
Prydz Bay ◽  
Element Fluxes

First glaciological investigations at Ridge B, central East Antarctica

2021 ◽  
pp. 1-10
Author(s):  
Alexey A. Ekaykin ◽  
Alexey V. Bolshunov ◽  
Vladimir Ya. Lipenkov ◽  
Mirko Scheinert ◽  
Lutz Eberlein ◽  
...  
Keyword(s):  
East Antarctica ◽  
Snow Density ◽  
Deep Drilling ◽  
Surface Mass ◽  
Annual Variations ◽  
First Results ◽  
Vostok Station ◽  
Water Stable Isotope ◽  
Isotope Content ◽  
Firn Core

Abstract The region of Ridge B in central East Antarctica is one of the last unexplored parts of the continent and, at the same time, ranks among the most promising places to search for Earth's oldest ice. In January 2020, we carried out the first scientific traverse from Russia's Vostok Station to the topographical dome of Ridge B (Dome B, 3807 m above sea level, 79.02°S, 93.69°E). The glaciological programme included continuous snow-radar profiling and geodetic positioning along the traverse's route, installation of snow stakes, measurements of snow density, collection of samples for stable water isotope and chemical analyses and drilling of a 20 m firn core. The first results of the traverse show that the surface mass balance at Dome B (2.28 g cm−2 year−1) is among the lowest in Antarctica. The firn temperature below the layer of annual variations is −58.1 ± 0.2°C. A very low value of heavy water stable isotope content (-58.2‰ for oxygen-18) was discovered at a distance of 170 km from Vostok Station. This work is the first step towards a comprehensive reconnaissance study of the Ridge B area aimed at locating the best site for future deep drilling for the oldest Antarctic ice.

210Pb based trace element fluxes in the nearshore and estuarine sediments off Bombay, India

1994 ◽  
Vol 47 (3-4) ◽  
pp. 227-241 ◽  
Author(s):  
P. Sharma ◽  
D.V. Borole ◽  
M.D. Zingde
Keyword(s):  
Trace Element ◽  
Estuarine Sediments ◽  
Element Fluxes

Natural variability and recent warming in central Greenland ice cores

2021 ◽  
Author(s):  
Maria Hoerhold ◽  
Thomas Münch ◽  
Stefanie Weißbach ◽  
Sepp Kipfstuhl ◽  
Bo Vinther ◽  
...  
Keyword(s):  
Climate Variability ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Ice Cores ◽  
Natural Variability ◽  
The Arctic ◽  
Last Millennium ◽  
Recent Warming ◽  
Temperature Reconstructions ◽  
Firn Core

<p>Climate variability of the Arctic region has been investigated by means of temperature reconstructions based on proxies from various climate archives around the Arctic, compiled over the last 2000a in the so called Arctic2k record. However, the representativeness of the Arctic2k reconstruction for central Greenland remains unclear, since only a few ice cores have been included in the reconstruction, and observations from the Greenland Ice Sheet (GIC) report ambiguous warming trends for the end of the 20th and the beginning of the 21st century which are not displayed by Arctic2k. Today, the GIC experiences periods with temperatures close to or above the freezing point at high elevations, area-wide melting and mass loss. In order to assess the recent warming as signature of global climate change, records of past climate changes with appropriate temporal and spatial coverage can serve as a benchmark for naturally driven climate variability. Instrumental records for Greenland are short and geographically sparse, and existing temperature reconstructions from single ice cores are noisy, leading to an inconclusive assessment of the recent warming for Greenland.</p><p>Here, we provide a Greenland firn-core stack covering the time span of the last millennium until the first decade of the 21<sup>st </sup>century in unprecedented quality by re-drilling as well as analyzing 16 existing firn core sites. We find a strong decadal to bi-decadal natural variability in the record, and, while the record exhibits several warming events with trends that show a similar amplitude as the recent one, we find that the recent absolute values of stable oxygen isotope composition are unprecedented for the last 1000 years.</p><p> </p><p>Comparing our Greenland record with the Arctic 2k temperature reconstruction shows that the correlation between the two records changes throughout the last millennium. While in the periods of 1200-1300 and 1400-1650 CE the records correlate positively, between 1300 and 1400 and 1650-1700 CE shorter periods with negative correlation are found. Since then the correlation is characterized by alternation between positive and zero correlation, with a drop towards negative values at the end of the 20<sup>th</sup> century. Including re-analysis data, we hypothesize that the climate on top of the GIC was decoupled from the surrounding Arctic for the last decades, leading to the observed mismatch in observations of warming trends.</p><p>We suggest that the recently observed Greenland temperatures are a superposition of a strong natural variability with an anthropogenic long-term trend. Our findings illustrate that global warming has reached the interior of the Greenland ice sheet, which will have implications for its surface mass balance and Greenland’s future contribution to sea level rise.</p><p>Our record complements the Arctic 2k record to a profound view on the Arctic climate variability, where regional compilations may not be representative for specific areas.</p>

Synoptic climatology of southern Indian Ocean and paleoclimate proxy interpretation

2021 ◽  
Author(s):  
Danielle Udy ◽  
Tessa Vance ◽  
Anthony Kiem ◽  
Neil Holbrook ◽  
Mark Curran
Keyword(s):  
Indian Ocean ◽  
Climate Variability ◽  
Large Scale ◽  
Ice Core ◽  
East Antarctica ◽  
Synoptic Climatology ◽  
Southern Indian Ocean ◽  
Westerly Wind ◽  
Weather Patterns ◽  
Modes Of Climate Variability

<p>Weather systems in the southern Indian Ocean drive synoptic-scale precipitation, temperature and wind variability in East Antarctica, sub-Antarctic islands and southern Australia.  Over seasonal to decadal timescales, the mean condition associated with combinations of these synoptic weather patterns (e.g., extratropical cyclones, fronts and regions of high pressure) is often referred to as variability in the westerly wind belt or the Southern Annular Mode (SAM). The westerly wind belt is generally considered to be zonally symmetric around Antarctica however, on a daily timescale this is not the case. To capture the daily variability of regional weather systems, we used synoptic typing (Self-Organising Maps) to group weather patterns based on similar features, which are often lost when using monthly or seasonal mean fields. We identified nine key regional weather types based on anomaly pattern and strength. These include four meridional nodes, three mixed nodes, one zonal node and one transitional node. The meridional nodes are favourable for transporting warm, moist air masses to the subantarctic and Antarctic region, and are associated with increased precipitation and temperature where the systems interact with the Antarctic coastline.  These nodes have limited association with the SAM, especially during austral spring.  In contrast, the zonal and mixed nodes were strongly correlated with the SAM however, the regional synoptic representation of SAM positive conditions is not zonally symmetric and is represented by three separate nodes.  These different types of SAM positive conditions mean that the commonly used hemispheric Marshall index often fails to capture the regional variability in surface weather conditions in the southern Indian Ocean. Our results show the importance of considering different synoptic set ups of SAM conditions, particularly SAM positive, and identify conditions that are potentially missed by SAM variability (e.g., extreme precipitation events). Our results are particularly important to consider when interpreting SAM or westerly wind belt reconstructions in the study region (from ice cores, tree rings, or lake sediments).  Here we present a case study using the synoptic typing results to enhance our understanding of the Law Dome (East Antarctica) ice core record, focussing on links to large scale modes of climate variability and Australian hydroclimate.  These results enhance the usefulness of ice core proxies in coastal East Antarctica and assist with determining where and how it is appropriate to use coastal East Antarctic ice core records for reconstructions of large scale modes of climate variability (e.g. SAM and ENSO) and remote hydroclimate conditions.</p>

Geochemical peat records from the Great Vasyugan Mire and Tomsk region, Siberia. Regional temporal trend of human impact over the last 500 years and local perturbations.

2021 ◽  
Author(s):  
Simon Hutchinson ◽  
Andrei Diaconu ◽  
Sergey Kirpotin ◽  
Angelica Feurdean
Keyword(s):  
Trace Element ◽  
Forest Cover ◽  
Human Impacts ◽  
Global Scale ◽  
Testate Amoeba ◽  
Dust Deposition ◽  
Peat Core ◽  
Element Concentrations ◽  
Local Perturbations ◽  
Geochemical Profile

<p>Although interest in peatland environments, especially in terms of their carbon storage, has gained momentum in response to a heightened awareness of the climate emergency; significant gaps remain in the geographical coverage of our knowledge of mires, including some major wetland systems. This paucity has implications, not only for our understanding of their development and functioning, but also for adequately predicting future changes and thus providing effective mire environmental management. Our INTERACT-supported study provides radiometrically dated, well-characterised millennial scale peat records from two contrasting undisturbed and impacted (ditched) ombrotrophic sites in the Great Vasyugan Mire (GVM) near Tomsk, Siberia and two additional mesotrophic sites to the east of the Ob river. In addition, the geochemical record was complemented by multiproxy palaeoecological characterisation (pollen, charcoal, stable isotopes, testate amoeba). We identified both natural (lithogenic) and anthropogenic geochemical signals recording human impacts with site specific variations. Elevated trace element concentrations in the peat profiles align with the region’s wider agricultural and economic development following the colonisation of Siberia by Russia (from ca. 1600 AD) when pollen assemblages indicate the decline of forest cover and an increase in human disturbance, including the use for fire. Trace element concentrations peak with the subsequent, post WWII industrialisation of regional centres in southern Siberia (after 1950 AD). On a global scale, our sites, together with evidence from the few other comparable studies in the region, suggest that the region’s peatlands are relatively uncontaminated by human activities with a mean lead (Pb) level of < 5 mg/kg. However, via lithogenic elements including Rb, Ti and Zr, we detected both a geochemical signal as a result of historical land cover changes enhancing mineral dust deposition following disturbance, as well as fossil fuel derived pollutants as relatively elevated, subsurface As and Pb concentrations of ca. 10 and 25 mg/kg respectively with the development of industry in the region. Nevertheless, the potential significance of local factors on the sites’ geochemical profile is also highlighted. For example, we identify the effects of past peat drainage for afforestation (ca. 1960s) and the scheme’s subsequent abandonment. Although the region’s mire systems are remote and vast, they appear to hold a legacy of human activity that can be detected as a geochemical signal supporting the inferences of other palaeoenvironmental proxies. Such geochemical peat core records, from Eurasia in particular, remain relatively scarce in the international scientific literature and therefore, as yet, inadequately characterised and quantified compared to other regions.</p>

Homogeneous climate variability across East Antarctica over the past three glacial cycles

Nature ◽  
2003 ◽  
Vol 422 (6931) ◽  
pp. 509-512 ◽  
Author(s):  
O. Watanabe ◽  
J. Jouzel ◽  
S. Johnsen ◽  
F. Parrenin ◽  
H. Shoji ◽  
...  
Keyword(s):  
Climate Variability ◽  
East Antarctica ◽  
Glacial Cycles ◽  
The Past
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