scholarly journals Radiocarbon analysis in an Alpine ice core: record of anthropogenic and biogenic contributions to carbonaceous aerosols in the past (1650–1940)

2006 ◽  
Vol 6 (12) ◽  
pp. 5381-5390 ◽  
Author(s):  
T. M. Jenk ◽  
S. Szidat ◽  
M. Schwikowski ◽  
H. W. Gäggeler ◽  
S. Brütsch ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Fossil Fuels ◽  
Ice Core ◽  
Anthropogenic Sources ◽  
Carbonaceous Aerosols ◽  
Range Analysis ◽  
Carbonaceous Particles ◽  
The Past ◽  
Time Period

Abstract. Long-term concentration records of carbonaceous particles (CP) are of increasing interest in climate research due to their not yet completely understood effects on climate. Nevertheless, only poor data on their concentrations and sources before the 20th century are available. We present a first long-term record of organic carbon (OC) and elemental carbon (EC) concentrations – the two main fractions of CP – along with the corresponding fraction of modern carbon (fM) derived from radiocarbon (14C) analysis in ice. This allows a distinction and quantification of natural (biogenic) and anthropogenic (fossil) sources in the past. CP were extracted from an ice archive, with resulting carbon quantities in the microgram range. Analysis of 14C by accelerator mass spectrometry (AMS) was therefore highly demanding. We analysed 33 samples of 0.4 to 1 kg ice from a 150.5 m long ice core retrieved at Fiescherhorn glacier in December 2002 (46°33'3.2" N, 08°04'0.4" E; 3900 m a.s.l.). Samples were taken from bedrock up to the firn/ice transition, covering the time period 1650–1940 and thus the transition from the pre-industrial to the industrial era. Before ~1850, OC was approaching a purely biogenic origin with a mean concentration of 24 μg kg−1 and a standard deviation of 7 μg kg−1. In 1940, OC concentration was about a factor of 3 higher than this biogenic background, almost half of it originating from anthropogenic sources, i.e. from combustion of fossil fuels. The biogenic EC concentration was nearly constant over the examined time period with 6 μg kg−1 and a standard deviation of 1 μg kg−1. In 1940, the additional anthropogenic input of atmospheric EC was about 50 μg kg−1.

scholarly journals Radiocarbon analysis in an Alpine ice core: record of anthropogenic and biogenic contributions to carbonaceous aerosols in the past (1650–1940)

2006 ◽  
Vol 6 (4) ◽  
pp. 5905-5931 ◽  
Author(s):  
T. M. Jenk ◽  
S. Szidat ◽  
M. Schwikowski ◽  
H. W. Gäggeler ◽  
S. Brütsch ◽  
...  
Keyword(s):  
Fossil Fuels ◽  
Ice Core ◽  
Anthropogenic Sources ◽  
Carbonaceous Aerosols ◽  
Range Analysis ◽  
Carbonaceous Particles ◽  
The Past ◽  
Time Period ◽  
Ice Core Record

Abstract. Long-term concentration records of carbonaceous particles (CP) are of increasing interest in climate research due to their not yet completely understood effects on climate. Nevertheless, only poor data on their concentrations and sources in the past is available. We present a first long-term record of organic carbon (OC) and elemental carbon (EC) concentrations - the two main fractions of CP – along with the corresponding fraction of modern carbon (fM) derived from radiocarbon (14C) analysis. The combination of concentration measurements with 14C analysis of CP allows a distinction and quantification of natural, biogenic and anthropogenic fossil sources in the past. CP were extracted from an ice archive, with resulting carbon quantities in the microgram range. Analysis of 14C by accelerator mass spectrometry (AMS) was therefore highly demanding. We analysed 33 samples of 0.4 to 1 kg ice from a 150.5 m long ice core retrieved at Fiescherhorn glacier in December 2002 (46°33'3.2" N, 08°04'0.4'' E; 3900 m a.s.l.). Samples were taken from below the firn/ice transition down to bedrock, covering the time period 1650–1940 and thus the transition from the pre-industrial to the industrial era. Before 1800, OC was of pure biogenic origin with a mean concentration of 21±2 μg kg−1}. In 1940, OC concentration was more than a factor of 3 higher than this biogenic background, almost half of it originating from anthropogenic sources, i.e. from combustion of fossil fuels. The biogenic EC concentration was nearly constant over the examined time period with 6±1 μg kg−1. In 1940, the additional anthropogenic input of atmospheric EC was about 50 μg kg−1.

The past 5000 years history of solar modulation of cosmic radiation from 10 Be and 14 C studies

1990 ◽  
Vol 330 (1615) ◽  
pp. 471-480 ◽  
Keyword(s):  
Cosmic Radiation ◽  
Ice Core ◽  
Ice Cores ◽  
Solar Modulation ◽  
Short Term ◽  
The Past ◽  
History Of ◽  
Long Term Trends ◽  
Terrestrial Biomass

10 Be is produced in a similar way as 14 C by the interaction of cosmic radiation with the nuclei in the atmosphere. Assuming that the 10 Be and 14 C variation are proportional and considering the different behaviour in the Earth system, the 10 Be concentrations in ice cores can be compared with the 14 C variations in tree rings. A high correlation is found for the short-term variations ( 14 C-Suess-wiggles). They reflect with a high probability production rate variations. More problematic is the interpretation of the long-term trends of 14 C and 10 Be. Several explanations are discussed. The reconstructed CO 2 concentrations in ice cores indicate a rather constant value (280 ± 10 p.p.m. by volume) during the past few millenia. Measurements on the ice core from Byrd Station, Antarctica, during the period 9000 to 6000 years BP indicate a decrease that might be explained by the extraction of CO 2 from the atmosphere-ocean system to build the terrestrial biomass pool during the climatic optimum.

scholarly journals Reconstruction of a continuous high-resolution CO<sub>2</sub> record over the past 20 million years

2011 ◽  
Vol 7 (4) ◽  
pp. 1459-1469 ◽  
Author(s):  
R. S. W. van de Wal ◽  
B. de Boer ◽  
L. J. Lourens ◽  
P. Köhler ◽  
R. Bintanja
Keyword(s):  
High Resolution ◽  
Sea Level ◽  
Northern Hemisphere ◽  
Climate Models ◽  
Ice Core ◽  
Co2 Concentration ◽  
Temperature Record ◽  
Absorption Bands ◽  
The Past

Abstract. The gradual cooling of the climate during the Cenozoic has generally been attributed to a decrease in CO2 concentration in the atmosphere. The lack of transient climate models and, in particular, the lack of high-resolution proxy records of CO2, beyond the ice-core record prohibit, however, a full understanding of, for example, the inception of the Northern Hemisphere glaciation and mid-Pleistocene transition. Here we elaborate on an inverse modelling technique to reconstruct a continuous CO2 series over the past 20 million year (Myr), by decomposing the global deep-sea benthic δ18O record into a mutually consistent temperature and sea level record, using a set of 1-D models of the major Northern and Southern Hemisphere ice sheets. We subsequently compared the modelled temperature record with ice core and proxy-derived CO2 data to create a continuous CO2 reconstruction over the past 20 Myr. Results show a gradual decline from 450 ppmv around 15 Myr ago to 225 ppmv for mean conditions of the glacial-interglacial cycles of the last 1 Myr, coinciding with a gradual cooling of the global surface temperature of 10 K. Between 13 to 3 Myr ago there is no long-term sea level variation caused by ice-volume changes. We find no evidence of change in the long-term relation between temperature change and CO2, other than the effect following the saturation of the absorption bands for CO2. The reconstructed CO2 record shows that the Northern Hemisphere glaciation starts once the long-term average CO2 concentration drops below 265 ppmv after a period of strong decrease in CO2. Finally, only a small long-term decline of 23 ppmv is found during the mid-Pleistocene transition, constraining theories on this major transition in the climate system. The approach is not accurate enough to revise current ideas about climate sensitivity.

Microanalytical Techniques for the Determination of Carbonaceous Aerosols in Remote Air and Snow Samples

1999 ◽  
Vol 5 (S2) ◽  
pp. 922-923
Author(s):  
D. Kessler ◽  
A. Currie ◽  
E. Newbury ◽  
E.S. Windsor
Keyword(s):  
Atmospheric Aerosols ◽  
Ice Core ◽  
Particle Removal ◽  
Carbonaceous Aerosols ◽  
Air Filter ◽  
Carbonaceous Particles ◽  
X Ray ◽  
Elemental Data ◽  
Combustion Processes

Remote ice core, snow, and air filter samples can potentially profile past and present atmospheric characteristics, acting as media to preserve populations of particulate matter. Major constituents of these aerosols derive from combustion processes (fossil and biomass) and airborne minerals. Extraction and characterization of these particles with scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS) provide morphological and elemental data used in determining the presence and sources of atmospheric aerosols. Due to the minute quantity of carbonaceous particles in the snow and ice samples, ca. 1-10 ng g-1, the microscopist faces several principal challenges to prepare and analyze these samples. First, methodology must be established for particle removal in a clean and quantitative fashion. Secondly, since carbon is contained in many of the particles under analysis, techniques must be established to achieve quantitative carbon X-ray data. The SEM requires optimization in order to analyze the greatest number of particles in the least time.

scholarly journals Reduced Seroma Risk in Drainless Abdominoplasty Using Running Barbed Sutures: A 10-Year, Multicenter Retrospective Analysis

2019 ◽  
Vol 40 (5) ◽  
pp. 531-537 ◽  
Author(s):  
Allen D Rosen ◽  
Karol A Gutowski ◽  
Teresa Hartman
Keyword(s):  
Risk Profile ◽  
Suture Techniques ◽  
Level Of Evidence ◽  
Barbed Sutures ◽  
The Past ◽  
Interrupted Suture ◽  
Time Period ◽  
Patient Series ◽  
Upper Abdominal

Abstract Background Drains are still commonly inserted during abdominoplasties despite extensive evidence documenting the benefits of drainless procedures. Continued improvements in progressive tension suturing (PTS) techniques and suture technologies have consistently shown a reduced seroma risk profile that outperforms procedures involving surgical drains. Objectives The aim of this report was to assess the authors’ combined patient series, which represents the largest and longest-running, retrospective, multicenter set of abdominoplasty patients treated with a PTS technique involving running barbed sutures. Methods Two surgical groups, each at different surgical centers, have for the past decade performed drainless abdominoplasties in which running barbed sutures were used. The results for all 445 patients in this series are reported by surgical center and pooled across centers. Results The majority of the 445 patients underwent drainless abdominoplasty alone (n = 368; 82.7%); most of the remaining patients did so as part of a circumferential body lift (n = 55; 12.4%). Overall, 33 (7.4%) patients experienced a postoperative complication. The overall seroma rate was 4.7% (21 of 445 patients), but this dropped to 2.3% after surgical technique modifications were made to decrease upper abdominal dead space. The seroma incidence in this series is markedly lower than the 13% seroma rate with drains reported during the same time period and comparable to those seen in drainless abdominoplasties with interrupted suture techniques. Conclusions Drainless abdominoplasty involving PTS with running barbed sutures shows long-term reproducibility in lowering seroma risk compared to techniques in which drains are inserted, supporting results from published series of drainless abdominoplasty procedures that use interrupted suture techniques. Level of Evidence: 4

scholarly journals Long-term (2001–2012) trends of carbonaceous aerosols from remote island in the western North Pacific: an outflow region of Asian pollutants and dust

2017 ◽  
Author(s):  
Suresh K. R. Boreddy ◽  
Md. Mozammel Haque ◽  
Kimitaka Kawamura
Keyword(s):  
Long Range ◽  
North Pacific ◽  
Western North Pacific ◽  
Atmospheric Transport ◽  
Organic Aerosols ◽  
Anthropogenic Sources ◽  
Carbonaceous Aerosols ◽  
Central Pacific ◽  
Air Masses

Abstract. The present study reports on long-term trends of carbonaceous aerosols in total suspended particulate (TSP) samples collected at Chichijima Island in the western North Pacific during 2001–2012. Seasonal variations of elemental, organic, and water-soluble organic carbon (EC, OC and WSOC) concentrations showed maxima in winter to spring and minima in summer. These seasonal differences in the concentrations of carbonaceous aerosols are associated with the outflows of polluted air masses from East Asia, which are clearly distinguishable from pristine air masses from the central Pacific. The higher concentrations of carbonaceous aerosols during winter to spring are associated with long-range atmospheric transport of East Asian polluted air masses, whereas lower concentrations may be due to pristine air masses from the central Pacific in summer. The annual trends of OC/EC, WSOC and WSOC/OC showed significant (p<0.05) increases during the period of 2001–2012, suggesting that an enhanced secondary formation of organic aerosols (SOA) via photochemical oxidation of anthropogenic and biogenic volatile organic compounds (VOCs) during long-range atmospheric transport. We found a significant increase in nss-K+/EC ratios, demonstrating that biomass burning-derived organic aerosols are increased, while combustion-derived anthropogenic sources are decreased over the western North Pacific. Further, secondary biogenic emissions are also important over the western North Pacific as inferred from a significant increase in the concentrations of methanesulfonate (MSA−, a tracer for biogenic source). We also found significant increases in OC/TC and WSOC/TC ratio, suggesting that contribution of SOA to total carbon (TC) are significantly increased over the western North Pacific followed by long-range atmospheric transport.

scholarly journals A Northern Hemisphere Volcanic Chemistry Record (1869–1984) and Climatic Implications Using a South Greenland Ice Core

1990 ◽  
Vol 14 ◽  
pp. 176-182 ◽  
Author(s):  
W.B. Lyons ◽  
P.A. Mayewski ◽  
M.J. Spencer ◽  
M.S. Twickler ◽  
T.E. Graedel
Keyword(s):  
Global Climate ◽  
Regional Climate ◽  
Ice Core ◽  
Volcanic Eruptions ◽  
Chemical Signatures ◽  
Time Period ◽  
Tree Ring Data ◽  
Long Term Trends ◽  
Major Chemical

The effect of volcanic emission of acidic aerosols on climate is well documented. The presence of acid droplets in the stratosphere can reduce transmissivity and hence decrease surface temperatures. Since the amount and chemical composition of erupted material has important effects on regional climate, knowledge of past volcanic events is of extreme importance. Detailed glaciochemical records provide the only milieu wherein the geochemistry of paleovolcanic events can be fully documented. We present a detailed sulfate and chloride record from an ice core drilled at site 20 D, 40 km SW of Dye 3 in southern Greenland. The record spans the time period 1869–1984 with chemical analyses of approximately eight samples per year. Time series decomposition and locally weighted scatter plot smoothing techniques were used to extract long term trends from the data so that individual volcanic eruptions could be documented. A number of events identified here have been unnoticed previously and a high percentage of the major chemical signatures documenting these events is associated with large decreases in temperature in the latitudinal zone 60–90 °N. Many authors have pointed out that the amount of volcanic acids such as HCl and H2SO4 injected into the atmosphere has a very important influence on global climate, yet this volcanic input has been difficult to quantify prior to ∼1960. Our data help to alleviate this problem. These individual events can be compared to available frost tree ring data from North America, further establishing a volcanism-climatic linkage.

scholarly journals A Northern Hemisphere Volcanic Chemistry Record (1869–1984) and Climatic Implications Using a South Greenland Ice Core

1990 ◽  
Vol 14 ◽  
pp. 176-182 ◽  
Author(s):  
W.B. Lyons ◽  
P.A. Mayewski ◽  
M.J. Spencer ◽  
M.S. Twickler ◽  
T.E. Graedel
Keyword(s):  
Global Climate ◽  
Regional Climate ◽  
Ice Core ◽  
Volcanic Eruptions ◽  
Chemical Signatures ◽  
Time Period ◽  
Tree Ring Data ◽  
Long Term Trends ◽  
Major Chemical

The effect of volcanic emission of acidic aerosols on climate is well documented. The presence of acid droplets in the stratosphere can reduce transmissivity and hence decrease surface temperatures. Since the amount and chemical composition of erupted material has important effects on regional climate, knowledge of past volcanic events is of extreme importance. Detailed glaciochemical records provide the only milieu wherein the geochemistry of paleovolcanic events can be fully documented. We present a detailed sulfate and chloride record from an ice core drilled at site 20 D, 40 km SW of Dye 3 in southern Greenland. The record spans the time period 1869–1984 with chemical analyses of approximately eight samples per year. Time series decomposition and locally weighted scatter plot smoothing techniques were used to extract long term trends from the data so that individual volcanic eruptions could be documented. A number of events identified here have been unnoticed previously and a high percentage of the major chemical signatures documenting these events is associated with large decreases in temperature in the latitudinal zone 60–90 °N. Many authors have pointed out that the amount of volcanic acids such as HCl and H2SO4injected into the atmosphere has a very important influence on global climate, yet this volcanic input has been difficult to quantify prior to ∼1960. Our data help to alleviate this problem. These individual events can be compared to available frost tree ring data from North America, further establishing a volcanism-climatic linkage.

Summary

2007 ◽  
Author(s):  
Robert May
Keyword(s):  
Fossil Fuels ◽  
Industrial Revolution ◽  
Global Climate ◽  
Ice Core ◽  
Sea Levels ◽  
The Past ◽  
Energy Demands ◽  
Co2 Levels ◽  
The Usa ◽  
History Of

Energy . . . Beyond Oil is important and timely and should be understood within the wider context of global climate change and future energy demands. In the 1780s John Watts developed his steam engine and so began the Industrial Revolution. At this time, ice-core records show that levels of CO2 in the atmosphere were around 288 parts per million (ppm). Give or take 10 ppm, this had been their level for the past 6,000 years, since the dawn of the first cities. As industrialization drove up the burning of fossil fuels in the developed world, CO2 levels rose. At first the rise was slow. It took about a century and a half to reach 315 ppm. The rise accelerated during the twentieth century: 330 ppm by the mid-1970s; 360 ppm by the 1990s; 380 ppm today. This change of 20 ppm over the past decade is equal to that last seen when the most recent ice age ended, ushering in the dawn of the Holocene epoch, 10,000 years ago. If current trends continue, then by about 2050 atmospheric CO2 levels will have reachedaround500 ppm, nearly double pre-industrial levels. The last time our planet experienced such high levels was some 50 million years ago, during the Eocene epoch, when sea levels were around100 m higher than today. The Dutch Nobelist, Paul Crutzen, has, indeed, suggested that we should recognize that we are now living in a new geological epoch, the Anthropocene. He sees this epoch as beginning around 1780, when industrialization began to change the geochemical history of our planet. Even today, there continues to exist a ‘denial lobby’, funded to the tune of tens of millions of dollars by sectors of the petrochemical industry, and highly influential in some countries. This lobby has understandable similarities, in tactics and attitudes, to the tobacco lobby that continues to deny smoking causes lung cancer, or the curious lobby denying that HIV causes AIDS. This denial lobby is currently very influential in the USA.

Do Holding Period Tax Incentives Affect Earnings Release Period Selling Activity of Individual Investors?

2004 ◽  
Vol 26 (2) ◽  
pp. 43-64 ◽  
Author(s):  
David N. Hurtt ◽  
Jim A. Seida
Keyword(s):  
Stock Price ◽  
Price Change ◽  
Tax Incentives ◽  
Individual Investors ◽  
Tax Rate ◽  
Holding Period ◽  
The Past ◽  
Time Period ◽  
Selling Decisions

This study examines the effect of tax-rate-based holding period incentives on individual investors' earnings release period selling decisions using selling activity proxies computed from intra-day transaction data. We find evidence that earnings release period selling activity, for a given level of past stock price appreciation (depreciation), is lower (higher) when the magnitude of the tax-rate incentive to hold long term is larger. The results are, however, sensitive to the time period used to compute the past stock price change variable. Although we report results consistent with income tax considerations influencing individual investors' selling decisions, the results cannot be definitively attributed to holding period incentives.

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