Impact of climate fluctuations on deposition of DDT and hexachlorocyclohexane in mountain glaciers: Evidence from ice core records

2010 ◽  
Vol 158 (2) ◽  
pp. 375-380 ◽  
Author(s):  
Xiaoping Wang ◽  
Ping Gong ◽  
Qianggong Zhang ◽  
Tandong Yao
2020 ◽  
pp. jgs2020-134
Author(s):  
P.L. Gibbard ◽  
P.D. Hughes

Initially, terrestrial evidence formed the foundation for the division of Quaternary time. However, since the 1970s there has been an abandonment of the terrestrial stage chronostratigraphy, which is based on locally dominated successions, in favour of the marine oxygen isotope stratigraphy which largely records global-scale changes in ice volume. However, it is now clear that glacial records around the world are asynchronous, even at the scale of the continental ice sheets which display marked contrasts in extent and timing in different glacial cycles. Consequently, the marine isotope record does not reflect global patterns of glaciation, or other terrestrial processes, on land. This has led to inappropriate correlation of terrestrial records with the marine isotopic record. The low resolution of the latter has led to a preferential shift towards high-resolution ice-core records for global correlation. However, even in the short term, most terrestrial records display spatial variation in response to global climate fluctuations, and changes recorded on land are often diachronous, asynchronous or both, leading to difficulties in global correlation. Thus, whilst the marine and the ice-core records are very useful in providing global frameworks through time, it must be recognized that there exist significant problems and challenges for terrestrial correlation.


2021 ◽  
Vol 34 (10) ◽  
pp. 3839-3852
Author(s):  
Stacy E. Porter ◽  
Ellen Mosley-Thompson ◽  
Lonnie G. Thompson ◽  
Aaron B. Wilson

AbstractUsing an assemblage of four ice cores collected around the Pacific basin, one of the first basinwide histories of Pacific climate variability has been created. This ice core–derived index of the interdecadal Pacific oscillation (IPO) incorporates ice core records from South America, the Himalayas, the Antarctic Peninsula, and northwestern North America. The reconstructed IPO is annually resolved and dates to 1450 CE. The IPO index compares well with observations during the instrumental period and with paleo-proxy assimilated datasets throughout the entire record, which indicates a robust and temporally stationary IPO signal for the last ~550 years. Paleoclimate reconstructions from the tropical Pacific region vary greatly during the Little Ice Age (LIA), although the reconstructed IPO index in this study suggests that the LIA was primarily defined by a weak, negative IPO phase and hence more La Niña–like conditions. Although the mean state of the tropical Pacific Ocean during the LIA remains uncertain, the reconstructed IPO reveals some interesting dynamical relationships with the intertropical convergence zone (ITCZ). In the current warm period, a positive (negative) IPO coincides with an expansion (contraction) of the seasonal latitudinal range of the ITCZ. This relationship is not stationary, however, and is virtually absent throughout the LIA, suggesting that external forcing, such as that from volcanoes and/or reduced solar irradiance, could be driving either the ITCZ shifts or the climate dominating the ice core sites used in the IPO reconstruction.


2013 ◽  
Vol 9 (4) ◽  
pp. 1403-1416 ◽  
Author(s):  
S. Preunkert ◽  
M. Legrand

Abstract. Seasonally resolved chemical ice core records available from the Col du Dôme glacier (4250 m elevation, French Alps), are here used to reconstruct past aerosol load and composition of the free European troposphere from before World War II to present. Available ice core records include inorganic (Na+, Ca2+, NH4+, Cl−, NO3−, and SO42−) and organic (carboxylates, HCHO, humic-like substances, dissolved organic carbon, water-insoluble organic carbon, and black carbon) compounds and fractions that permit reconstructing the key aerosol components and their changes over the past. It is shown that the atmospheric load of submicron aerosol has been increased by a factor of 3 from the 1921–1951 to 1971–1988 years, mainly as a result of a large increase of sulfate (a factor of 5), ammonium and water-soluble organic aerosol (a factor of 3). Thus, not only growing anthropogenic emissions of sulfur dioxide and ammonia have caused the enhancement of the atmospheric aerosol load but also biogenic emissions producing water-soluble organic aerosol. This unexpected change of biospheric source of organic aerosol after 1950 needs to be considered and further investigated in scenarios dealing with climate forcing by atmospheric aerosol.


2017 ◽  
Vol 44 (17) ◽  
pp. 9084-9092 ◽  
Author(s):  
J. Scott Hosking ◽  
Ryan Fogt ◽  
Elizabeth R. Thomas ◽  
Vahid Moosavi ◽  
Tony Phillips ◽  
...  

2021 ◽  
Author(s):  
Florian Ritterbusch ◽  
Jinho Ahn ◽  
Ji-Qiang Gu ◽  
Wei Jiang ◽  
Giyoon Lee ◽  
...  

<p>Paleoclimate reconstructions from ice core records can be hampered due to the lack of a reliable chronology, especially when the stratigraphy is disturbed and conventional dating methods cannot be readily applied. The noble-gas radioisotopes <sup>81</sup>Kr and <sup>39</sup>Ar can in these cases provide robust constraints as they yield absolute, radiometric ages. <sup>81</sup>Kr (half-life 229 ka) covers the time span of 50-1300 ka, which is particularly relevant for polar ice cores, whereas <sup>39</sup>Ar (half-life 269 a) with a dating range of 50-1800 a is suitable for high mountain glaciers. For a long time the use of <sup>81</sup>Kr and <sup>39</sup>Ar for dating of ice samples was hampered by the lack of a detection technique that can meet its extremely small abundance at a reasonable sample size.</p><p>Here, we present <sup>81</sup>Kr and <sup>39</sup>Ar dating of Antarctic and Tibetan ice cores with the detection method Atom Trap Trace Analysis (ATTA), using 5-10 kg of ice for <sup>81</sup>Kr and 2-5 kg for <sup>39</sup>Ar. Recent advances in further decreasing the sample size and increasing the dating precision will be discussed. Current studies include <sup>81</sup>Kr dating in shallow ice cores from the Larsen Blue ice area, East Antarctica, in order to retrieve climate signals from the last glacial termination. Moreover, an <sup>39</sup>Ar profile from a central Tibetan ice core has been obtained in combination with layer counting based on isotopic and visual stratigraphic signals. The presented studies demonstrate how <sup>81</sup>Kr and <sup>39</sup>Ar can constrain the age range of ice cores and complement other methods in developing an ice core chronology.</p><p> </p><p>[1] Z.-T. Lu, Tracer applications of noble gas radionuclides in the geosciences, Earth-Science Reviews 138, 196-214, (2014)<br>[2] C. Buizert, Radiometric <sup>81</sup>Kr dating identifies 120,000-year-old ice at Taylor Glacier, Antarctica, Proceedings of the National Academy of Sciences, <strong>111</strong>, 6876, (2014)</p><p>[3] L. Tian, <sup>81</sup>Kr Dating at the Guliya Ice Cap, Tibetan Plateau, Geophysical Research Letters, (2019)</p><p>http://atta.ustc.edu.cn</p>


2021 ◽  
Author(s):  
Imogen Gabriel ◽  
Gill Plunkett ◽  
Peter Abbott ◽  
Bergrún Óladóttir ◽  
Joseph McConnell ◽  
...  

<p>Volcanic eruptions are considered as one of the primary natural drivers for changes in the global climate system and understanding the impact of past eruptions on the climate is integral to adopt appropriate responses towards future volcanic eruptions.</p><p>The Greenland ice core records are dominated by Icelandic eruptions, with several volcanic systems (Katla, Hekla, Bárðarbunga-Veiðivötn and Grimsvötn) being highly active throughout the Holocene. A notable period of increased Icelandic volcanic activity occurred between 500-1250 AD and coincided with climatic changes in the North Atlantic region which may have facilitated the Viking settlement of Greenland and Iceland. However, a number of these volcanic events are poorly constrained (duration and magnitude). Consequently, the Greenland ice cores offer the opportunity to reliably reconstruct past Icelandic volcanism (duration, magnitude and frequency) due to their high-resolution, the proximity of Iceland to Greenland and subsequent increased likelihood of volcanic fallout deposits (tephra particles and sulphur aerosols) being preserved. However, both the high frequency of eruptions between 500-1250 AD and the geochemical similarity of Iceland’s volcanic centres present challenges in making the required robust geochemical correlations between the source volcano and the ice core records and ultimately reliably assessing the climatic-societal impacts of these eruptions.</p><p>To address this, we use two Greenland ice core records (TUNU2013 and B19) and undertake geochemical analysis on tephra from the volcanic events in the selected time window which have been detected and sampled using novel techniques (insoluble particle peaks and sulphur acidity peaks). Further geochemical analysis of proximal material enables robust correlations to be made between the events in the ice core records and their volcanic centres. The high-resolution of these polar archives provides a precise age for the event and when utilised alongside other proxies (i.e. sulphur aerosols), both the duration and magnitude of these eruptions can be constrained, and the climatic-societal impacts of these eruptions reliably assessed.</p>


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