ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Proceed order?

Export
  • 1
    Publication Date: 2015-12-17
    Description: Continental dust plays an important role in climate forcing, by interacting with incoming solar and outgoing long wave radiation and by impacting albedo when deposited on bright surfaces such as fresh snow. Continental dust may also play an important role in ocean fertilization and carbon sequestration. Because the lifetime of dust aerosol in the atmosphere is only on the order of days to weeks, spatial and temporal variability in concentrations and fluxes is high and understanding of recent and long term changes is limited. Therefore, understanding of natural variations and climate drivers of continental dust, and potential climate feedbacks on longer timescales is critical. Here we present and discuss continuous, high depth resolution measurements of a range of dust proxies in high latitude ice cores from the Arctic and Antarctic. Sub-annually resolved measurements provide insights into the temporal variations in dust deposition. Included are traditional proxies such as non-sea-salt (nss) calcium and insoluble particle number and size distribution as well as less traditional proxies such as rare earth elements which together provide important insights into how dust sources and transport may have changed in the past. We compare these detailed dust records with climate and land use proxies to investigate drivers of dustiness during the last three millennium.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , NonPeerReviewed
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Publication Date: 2016-11-14
    Description: Assessments of climate sensitivity to projected greenhouse gas concentrations underpin environmental policy decisions, with such assessments often based on model simulations of climate during recent centuries and millennia1, 2, 3. These simulations depend critically on accurate records of past aerosol forcing from global-scale volcanic eruptions, reconstructed from measurements of sulphate deposition in ice cores4, 5, 6. Non-uniform transport and deposition of volcanic fallout mean that multiple records from a wide array of ice cores must be combined to create accurate reconstructions. Here we re-evaluated the record of volcanic sulphate deposition using a much more extensive array of Antarctic ice cores. In our new reconstruction, many additional records have been added and dating of previously published records corrected through precise synchronization to the annually dated West Antarctic Ice Sheet Divide ice core7, improving and extending the record throughout the Common Era. Whereas agreement with existing reconstructions is excellent after 1500, we found a substantially different history of volcanic aerosol deposition before 1500; for example, global aerosol forcing values from some of the largest eruptions (for example, 1257 and 1458) previously were overestimated by 20–30% and others underestimated by 20–50%.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , NonPeerReviewed
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Publication Date: 2017-01-24
    Description: Advances in trace gas analysis allow localised, non-atmospheric features to be resolved in ice cores, superimposed on the coherent atmospheric signal. These highfrequency signals could not have survived the low-pass filter effect that gas diffusion in the firn exerts on the atmospheric history and therefore do not result from changes in the atmospheric composition at the ice sheet surface. Using continuous methane (CH4) records obtained from five polar ice cores, we characterise these non-atmospheric signals and explore their origin. Isolated samples, enriched in CH4 in the Tunu13 (Greenland) record are linked to the presence of melt layers. Melting can enrich the methane concentration due to a solubility effect, but we find that an additional in situ process is required to generate the full magnitude of these anomalies. Furthermore, in all the ice cores studied there is evidence of reproducible, decimetre-scale CH4 variability. Through a series of tests, we demonstrate that this is an artifact of layered bubble trapping in a heterogeneousdensity firn column; we use the term “trapping signal” for this phenomenon. The peak-to-peak amplitude of the trapping signal is typically 5 ppb, but may exceed 40 ppb. Signal magnitude increases with atmospheric CH4 growth rate and seasonal density contrast, and decreases with accumulation rate. Significant annual periodicity is present in the CH4 variability of two Greenland ice cores, suggesting that layered gas trapping at these sites is controlled by regular, seasonal variations in the physical properties of the firn. Future analytical campaigns should anticipate high-frequency artifacts at high-melt ice core sites or during time periods with high atmospheric CH4 growth rate in order to avoid misinterpretation of such features as past changes in atmospheric composition.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , NonPeerReviewed
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Publication Date: 2018-01-02
    Description: Glacial-state greenhouse gas concentrations and Southern Hemisphere climate conditions persisted until ∼17.7 ka, when a nearly synchronous acceleration in deglaciation was recorded in paleoclimate proxies in large parts of the Southern Hemisphere, with many changes ascribed to a sudden poleward shift in the Southern Hemisphere westerlies and subsequent climate impacts. We used high-resolution chemical measurements in the West Antarctic Ice Sheet Divide, Byrd, and other ice cores to document a unique, ∼192-y series of halogen-rich volcanic eruptions exactly at the start of accelerated deglaciation, with tephra identifying the nearby Mount Takahe volcano as the source. Extensive fallout from these massive eruptions has been found 〉2,800 km from Mount Takahe. Sulfur isotope anomalies and marked decreases in ice core bromine consistent with increased surface UV radiation indicate that the eruptions led to stratospheric ozone depletion. Rather than a highly improbable coincidence, circulation and climate changes extending from the Antarctic Peninsula to the subtropics—similar to those associated with modern stratospheric ozone depletion over Antarctica—plausibly link the Mount Takahe eruptions to the onset of accelerated Southern Hemisphere deglaciation ∼17.7 ka.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , NonPeerReviewed
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1572-9028
    Keywords: reforming ; methane ; carbon dioxide ; Rh/SiO2 ; vanadia-promoted Rh/SiO2 ; FTIR spectroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The reforming of methane with carbon dioxide over rhodium dispersed on silica, Rh/SiO2, and vanadia-promoted silica, Rh/VOx/SiO2, was studied by kinetic test reactions under differential conditions in a temperature range from 723 to 773 K. Transmission infrared spectroscopy was applied to observe the interaction of CO2 with the catalysts and the formation of surface intermediates during the CO2–CH4 reforming reaction. To analyze carbon deposition XP spectroscopy and TPO was carried out. It has been shown that the promotion of Rh/SiO2 catalysts with vanadium oxide enhances the catalytic activity for CO2 reforming of methane and decreases the deactivation by carbon deposition. This is attributed to the formation of a partial VOx overlayer on the Rh surface, which reduces the size of accessible ensembles of Rh atoms required for coke formation and creates new sites at the Rh–VOx interfacial region that are considered to be active sites for the activation/dissociation of carbon dioxide.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Publication Date: 2019-02-01
    Description: Volcanic activity in and around the year 536 CE led to severe cold and famine, and has been speculatively linked to large-scale societal crises around the globe. Using a coupled aerosol-climate model, with eruption parameters constrained by recently re-dated ice core records and historical observations of the aerosol cloud, we reconstruct the radiative forcing resulting from a sequence of two major volcanic eruptions in 536 and 540 CE. We estimate that the decadal-scale Northern Hemisphere (NH) extra-tropical radiative forcing from this volcanic “double event” was larger than that of any period in existing reconstructions of the last 1200 years. Earth system model simulations including the volcanic forcing show peak NH mean temperature anomalies reaching more than −2 °C, and show agreement with the limited number of available maximum latewood density temperature reconstructions. The simulations also produce decadal-scale anomalies of Arctic sea ice. The simulated cooling is interpreted in terms of probable impacts on agricultural production in Europe, and implies a high likelihood of multiple years of significant decreases in crop production across Scandinavia, supporting the theory of a connection between the 536 and 540 eruptions and evidence of societal crisis dated to the mid-6th century.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Publication Date: 2017-04-21
    Description: Wildfires and their emissions have significant impacts on ecosystems, climate, atmospheric chemistry, and carbon cycling. Well-dated proxy records are needed to study the long-term climatic controls on biomass burning and the associated climate feedbacks. There is a particular lack of information about long-term biomass burning variations in Siberia, the largest forested area in the Northern Hemisphere. In this study we report analyses of aromatic acids (vanillic and para-hydroxybenzoic acids) over the past 2600 years in the Eurasian Arctic Akademii Nauk ice core. These compounds are aerosol-borne, semi-volatile organic compounds derived from lignin combustion. The analyses were made using ion chromatography with electrospray mass spectrometric detection. The levels of these aromatic acids ranged from below the detection limit (0.01 to 0.05 ppb; 1 ppb D1000 ng L-1) to about 1 ppb, with roughly 30% of the samples above the detection limit. In the preindustrial late Holocene, highly elevated aromatic acid levels are observed during three distinct periods (650–300 BCE, 340–660 CE, and 1460–1660 CE). The timing of the two most recent periods coincides with the episodic pulsing of ice-rafted debris in the North Atlantic known as Bond events and a weakened Asian monsoon, suggesting a link between fires and large-scale climate variability on millennial timescales. Aromatic acid levels also are elevated during the onset of the industrial period from 1780 to 1860 CE, but with a different ratio of vanillic and para-hydroxybenzoic acid than is observed during the preindustrial period. This study provides the first millennial-scale record of aromatic acids. This study clearly demonstrates that coherent aromatic acid signals are recorded in polar ice cores that can be used as proxies for past trends in biomass burning.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , NonPeerReviewed
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Publication Date: 2017-07-21
    Description: Reproducible climate reconstructions of the Common Era (1 CE to present) are key to placing industrial-era warming into the context of natural climatic variability. Here we present a community-sourced database of temperature-sensitive proxy records from the PAGES2k initiative. The database gathers 692 records from 648 locations, including all continental regions and major ocean basins. The records are from trees, ice, sediment, corals, speleothems, documentary evidence, and other archives. They range in length from 50 to 2000 years, with a median of 547 years, while temporal resolution ranges from biweekly to centennial. Nearly half of the proxy time series are significantly correlated with HadCRUT4.2 surface temperature over the period 1850–2014. Global temperature composites show a remarkable degree of coherence between high- and low-resolution archives, with broadly similar patterns across archive types, terrestrial versus marine locations, and screening criteria. The database is suited to investigations of global and regional temperature variability over the Common Era, and is shared in the Linked Paleo Data (LiPD) format, including serializations in Matlab, R and Python.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , NonPeerReviewed
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Publication Date: 2017-01-04
    Description: Author Posting. © American Geophysical Union, 2014. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Atmospheres 119 (2014): 9168–9182, doi:10.1002/2013JD020720.
    Description: The sources and transport pathways of aerosol species in Antarctica remain uncertain, partly due to limited seasonally resolved data from the harsh environment. Here, we examine the seasonal cycles of major ions in three high-accumulation West Antarctic ice cores for new information regarding the origin of aerosol species. A new method for continuous acidity measurement in ice cores is exploited to provide a comprehensive, charge-balance approach to assessing the major non-sea-salt (nss) species. The average nss-anion composition is 41% sulfate (SO42−), 36% nitrate (NO3−), 15% excess-chloride (ExCl−), and 8% methanesulfonic acid (MSA). Approximately 2% of the acid-anion content is neutralized by ammonium (NH4+), and the remainder is balanced by the acidity (Acy ≈ H+ − HCO3−). The annual cycle of NO3− shows a primary peak in summer and a secondary peak in late winter/spring that are consistent with previous air and snow studies in Antarctica. The origin of these peaks remains uncertain, however, and is an area of active research. A high correlation between NH4+ and black carbon (BC) suggests that a major source of NH4+ is midlatitude biomass burning rather than marine biomass decay, as previously assumed. The annual peak in excess chloride (ExCl−) coincides with the late-winter maximum in sea ice extent. Wintertime ExCl− is correlated with offshore sea ice concentrations and inversely correlated with temperature from nearby Byrd station. These observations suggest that the winter peak in ExCl− is an expression of fractionated sea-salt aerosol and that sea ice is therefore a major source of sea-salt aerosol in the region.
    Description: This work was supported by grants from the NSF Antarctic Program (0632031 and 1142166), NSF-MRI (1126217), the NASA Cryosphere Program (NNX10AP09G), and by an award from the Department of Energy Office of Science Graduate Fellowship Program (DOE SCGF) to ASC.
    Description: 2015-01-21
    Keywords: Antarctica ; Ice cores ; Biomass burning ; Sea ice ; Nitrate ; Acidity
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Publication Date: 2017-09-13
    Description: © The Author(s), 2014. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 4 (2014): 5848, doi:10.1038/srep05848.
    Description: Interior Antarctica is among the most remote places on Earth and was thought to be beyond the reach of human impacts when Amundsen and Scott raced to the South Pole in 1911. Here we show detailed measurements from an extensive array of 16 ice cores quantifying substantial toxic heavy metal lead pollution at South Pole and throughout Antarctica by 1889 – beating polar explorers by more than 22 years. Unlike the Arctic where lead pollution peaked in the 1970s, lead pollution in Antarctica was as high in the early 20th century as at any time since industrialization. The similar timing and magnitude of changes in lead deposition across Antarctica, as well as the characteristic isotopic signature of Broken Hill lead found throughout the continent, suggest that this single emission source in southern Australia was responsible for the introduction of lead pollution into Antarctica at the end of the 19th century and remains a significant source today. An estimated 660 t of industrial lead have been deposited over Antarctica during the past 130 years as a result of mid-latitude industrial emissions, with regional-to-global scale circulation likely modulating aerosol concentrations. Despite abatement efforts, significant lead pollution in Antarctica persists into the 21st century.
    Description: This work primarily was supported by the U.S. National Science Foundation Division of Polar Programs (research grants 9903744, 0538427, 0538416, 0968391, 1142166, 0632031; instrument grants 0216552, 0421412).
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/vnd.ms-excel
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...