scholarly journals A 156 kyr smoothed history of the atmospheric greenhouse gases CO<sub>2</sub>, CH<sub>4</sub>, and N<sub>2</sub>O and their radiative forcing

2017 ◽  
Vol 9 (1) ◽  
pp. 363-387 ◽  
Author(s):  
Peter Köhler ◽  
Christoph Nehrbass-Ahles ◽  
Jochen Schmitt ◽  
Thomas F. Stocker ◽  
Hubertus Fischer
Keyword(s):  
Time Series ◽  
Greenhouse Gases ◽  
Radiative Forcing ◽  
Ice Core ◽  
Ice Cores ◽  
Data Compilation ◽  
History Of ◽  
Data Points ◽  
Ch4 And N2o ◽  
The Individual

Abstract. Continuous records of the atmospheric greenhouse gases (GHGs) CO2, CH4, and N2O are necessary input data for transient climate simulations, and their associated radiative forcing represents important components in analyses of climate sensitivity and feedbacks. Since the available data from ice cores are discontinuous and partly ambiguous, a well-documented decision process during data compilation followed by some interpolating post-processing is necessary to obtain those desired time series. Here, we document our best possible data compilation of published ice core records and recent measurements on firn air and atmospheric samples spanning the interval from the penultimate glacial maximum ( ∼  156 kyr BP) to the beginning of the year 2016 CE. We use the most recent age scales for the ice core data and apply a smoothing spline method to translate the discrete and irregularly spaced data points into continuous time series. These splines are then used to compute the radiative forcing for each GHG using well-established, simple formulations. We compile only a Southern Hemisphere record of CH4 and discuss how much larger a Northern Hemisphere or global CH4 record might have been due to its interpolar difference. The uncertainties of the individual data points are considered in the spline procedure. Based on the given data resolution, time-dependent cutoff periods of the spline, defining the degree of smoothing, are prescribed, ranging from 5000 years for the less resolved older parts of the records to 4 years for the densely sampled recent years. The computed splines seamlessly describe the GHG evolution on orbital and millennial timescales for glacial and glacial–interglacial variations and on centennial and decadal timescales for anthropogenic times. Data connected with this paper, including raw data and final splines, are available at doi:10.1594/PANGAEA.871273.

scholarly journals Continuous records of the atmospheric greenhouse gases CO<sub>2</sub>, CH<sub>4</sub>, and N<sub>2</sub>O and their radiative forcing since the penultimate glacial maximum

2017 ◽  
Author(s):  
Peter Köhler ◽  
Christoph Nehrbass-Ahles ◽  
Jochen Schmitt ◽  
Thomas F. Stocker ◽  
Hubertus Fischer
Keyword(s):  
Time Series ◽  
Greenhouse Gases ◽  
Time Scales ◽  
Radiative Forcing ◽  
Time Window ◽  
Ice Core ◽  
Ice Cores ◽  
Glacial Maximum ◽  
Mixing Ratios ◽  
Data Compilation

Abstract. Continuous records of the atmospheric greenhouse gases (GHGs) CO2, CH4, and N2O are necessary input data for transient climate simulations and their related radiative forcing important components in analyses of climate sensitivity and feedbacks. Since the available data from ice cores are discontinuous and partly ambiguous a well-documented decision process during data compilation followed by some interpolating post-processing are necessary to obtain those desired time series. Here we document our best-guess data compilation of published ice core records and recent measurements on firn air and atmospheric samples covering the time window from the penultimate glacial maximum (∼ 156 kyr BP) to the beginning of year 2016 CE. A smoothing spline method is applied to translate the discrete and irregularly spaced data points into continuous time series. These splines are assumed to represent the evolution of the atmospheric mixing ratios for the three GHGs. Global- mean radiative forcing for each GHG is computed using well-established, simple formulations. Newest published age scales are used for the ice core data. While CO2 is representing an integrated global signal, we compile only a southern hemisphere record of CH4 and identify how much larger a northern hemisphere or global CH4 record might have been due to its interhemispheric gradient. Data resolution and uncertainties are considered in the spline procedure and typical cutoff periods, defining the degree of smoothing, range from 5000 years for the less resolved older parts of the records to 4 years for the densely-sampled recent years. The data sets describe seamlessly the GHG evolution on orbital and millennial time scales for glacial and glacial-interglacial variations and on centennial and decadal time scales for anthropogenic times. Data connected with this paper, including raw data and final splines, are available at https://doi.pangaea.de/10.1594/PANGAEA.871273.

scholarly journals Atmospheric CO2, CH4 and N2O records over the past 60 000 years based on the comparison of different polar ice cores

2002 ◽  
Vol 35 ◽  
pp. 202-208 ◽  
Author(s):  
Bernard Stauffer ◽  
Jacqueline Flückiger ◽  
Eric Monnin ◽  
Jakob Schwander ◽  
Jean-Marc Barnola ◽  
...  
Keyword(s):  
Greenhouse Gases ◽  
Anthropogenic Activities ◽  
Ice Core ◽  
Ice Cores ◽  
Analytical Techniques ◽  
Polar Ice ◽  
Short Term ◽  
The Past ◽  
Glacial Epoch ◽  
Ch4 And N2o

AbstractAnalyses of air extracted from polar ice cores are the most straightforward method of reconstructing the atmospheric concentrations of greenhouse gases and their variations for past climatic epochs. These measurements show that the concentration of the three most important greenhouse gases (other than water vapour) CO2, CH4 and N2O have steadily increased during the past 250 years due to anthropogenic activities (Prather and others, 2001; Prentice and others, 2001). Ice-core results also provided the first evidence of a substantial increase in the concentration of the three gases during the transition from the last glacial epoch to the Holocene (Raynaud and others, 1993). However, results from different cores are not always in agreement concerning details and small, short-term variations. the composition of the air enclosed in bubbles can be slightly changed by fractionation during the enclosure process, by chemical reactions and/or biological activity in the ice and by fractionation during the air extraction. We compile here several records with short-term variations or anomalies and discuss possible causes, taking into account improved analytical techniques and new results.

scholarly journals Improved estimates of preindustrial biomass burning reduce the magnitude of aerosol climate forcing in the Southern Hemisphere

2021 ◽  
Vol 7 (22) ◽  
pp. eabc1379
Author(s):  
Pengfei Liu ◽  
Jed O. Kaplan ◽  
Loretta J. Mickley ◽  
Yang Li ◽  
Nathan J. Chellman ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
Radiative Forcing ◽  
Ice Core ◽  
Ice Cores ◽  
Terrestrial Ecosystems ◽  
Rapid Expansion ◽  
Past Century ◽  
Fire Emissions ◽  
The Past ◽  
Fire Activity

Fire plays a pivotal role in shaping terrestrial ecosystems and the chemical composition of the atmosphere and thus influences Earth’s climate. The trend and magnitude of fire activity over the past few centuries are controversial, which hinders understanding of preindustrial to present-day aerosol radiative forcing. Here, we present evidence from records of 14 Antarctic ice cores and 1 central Andean ice core, suggesting that historical fire activity in the Southern Hemisphere (SH) exceeded present-day levels. To understand this observation, we use a global fire model to show that overall SH fire emissions could have declined by 30% over the 20th century, possibly because of the rapid expansion of land use for agriculture and animal production in middle to high latitudes. Radiative forcing calculations suggest that the decreasing trend in SH fire emissions over the past century largely compensates for the cooling effect of increasing aerosols from fossil fuel and biofuel sources.

Climate Change: What’s the Big Deal?

2019 ◽  
pp. 7-22
Author(s):  
Gilbert E. Metcalf
Keyword(s):  
Climate Change ◽  
Greenhouse Gases ◽  
Sea Level Rise ◽  
Sea Level ◽  
Ice Core ◽  
Core Samples ◽  
History Of ◽  
The Cost ◽  
Climate Damages

Droughts, floods, soaring temperatures, sea-level rise, and melting ice are just some of the damages brought about by climate change. Chapter 1 details the cost of our failure to cut our emissions, from crop-destroying droughts to devastating floods. It also documents the inexorable build-up of greenhouse gases in the atmosphere as demonstrated by the Keeling curve and observations from Antarctic ice core samples. The chapter then provides a brief history of the science linking the build-up of atmospheric greenhouse gases and climate damages.

scholarly journals The Atmospheric δ13C Record as Derived from 56 Pinyon Trees at 14 Sites in the Southwestern United States

Radiocarbon ◽  
1989 ◽  
Vol 31 (03) ◽  
pp. 469-474 ◽  
Author(s):  
S W Leavitt ◽  
Austin Long
Keyword(s):  
High Frequency ◽  
Ice Core ◽  
Ring Width ◽  
Ice Cores ◽  
The Other ◽  
Core Data ◽  
Single Tree ◽  
Pinyon Pine ◽  
The Individual ◽  
First Time

We have developed a master δ13C chronology from 14 pinyon pine sites in 6 states of the southwestern U S. Two of the individual isotopic chronologies, reported here for the first time, and 10 of those previously reported (Leavitt &amp; Long, 1986; 1988) are from sites where cores from 4 trees were pooled prior to analysis, and the other 2 are merged from groups of 4 single-tree chronologies (sites) developed in an earlier phase of research (Leavitt &amp; Long, 1985). Regressions of first differences of ring-width indices and δ13C values from each site were used to “correct” individual δ13C chronologies for climate effects which appear primarily related to high-frequency δ13C fluctuations, many of which are common among sites. These climate-corrected chronologies were normalized as deviations from their respective 1800–1849 δ13C means, and these normalized chronologies were averaged into the master. The overall δ13C drop from 1600 to the present is ca 1.2–1.4, consistent with recent ice-core data showing a drop of 1.14 ± 0.15% from 1740 to present (Friedli et al, 1986). However, the δ13C decline in the late 19th and early 20th centuries is greater in the pinyon chronology than that of the ice cores, thus supporting a greater biospheric CO2 input to the atmosphere than that indicated in the ice-core data.

scholarly journals Using Artificial Neural Networks for Equalizing Time Series Considering Seasonal Fluctuations

2019 ◽  
Vol 71 ◽  
pp. 01003
Author(s):  
J. Vrbka ◽  
J. Horák ◽  
V. Machová
Keyword(s):  
Neural Networks ◽  
Time Series ◽  
Artificial Neural Networks ◽  
Seasonal Fluctuations ◽  
Republic Of China ◽  
The People ◽  
Data Points ◽  
Artificial Neural ◽  
The Individual

The objective of this contribution is to prepare a methodology of using artificial neural networks for equalizing time series when considering seasonal fluctuations on the example of the Czech Republic import from the People´s Republic of China. If we focus on the relation of neural networks and time series, it is possible to state that both the purpose of time series themselves and the nature of all the data are what matters. The purpose of neural networks is to record the process of time series and to forecast individual data points in the best possible way. From the discussion part it follows that adding other variables significantly improves the quality of the equalized time series. Not only the performance of the networks is very high, but the individual MLP networks are also able to capture the seasonal fluctuations in the development of the monitored variable, which is the CR import from the PRC.

scholarly journals Temperature and mineral dust variability recorded in two low-accumulation Alpine ice cores over the last millennium

2018 ◽  
Vol 14 (1) ◽  
pp. 21-37 ◽  
Author(s):  
Pascal Bohleber ◽  
Tobias Erhardt ◽  
Nicole Spaulding ◽  
Helene Hoffmann ◽  
Hubertus Fischer ◽  
...  
Keyword(s):  
Time Series ◽  
Mineral Dust ◽  
Ice Core ◽  
Ice Cores ◽  
Temperature Reconstruction ◽  
Relative Increase ◽  
Ice Age ◽  
European Alps ◽  
Stable Water Isotopes ◽  
Annual Layer

Abstract. Among ice core drilling sites in the European Alps, Colle Gnifetti (CG) is the only non-temperate glacier to offer climate records dating back at least 1000 years. This unique long-term archive is the result of an exceptionally low net accumulation driven by wind erosion and rapid annual layer thinning. However, the full exploitation of the CG time series has been hampered by considerable dating uncertainties and the seasonal summer bias in snow preservation. Using a new core drilled in 2013 we extend annual layer counting, for the first time at CG, over the last 1000 years and add additional constraints to the resulting age scale from radiocarbon dating. Based on this improved age scale, and using a multi-core approach with a neighbouring ice core, we explore the time series of stable water isotopes and the mineral dust proxies Ca2+ and insoluble particles. Also in our latest ice core we face the already known limitation to the quantitative use of the stable isotope variability based on a high and potentially non-stationary isotope/temperature sensitivity at CG. Decadal trends in Ca2+ reveal substantial agreement with instrumental temperature and are explored here as a potential site-specific supplement to the isotope-based temperature reconstruction. The observed coupling between temperature and Ca2+ trends likely results from snow preservation effects and the advection of dust-rich air masses coinciding with warm temperatures. We find that if calibrated against instrumental data, the Ca2+-based temperature reconstruction is in robust agreement with the latest proxy-based summer temperature reconstruction, including a “Little Ice Age” cold period as well as a medieval climate anomaly. Part of the medieval climate period around AD 1100–1200 clearly stands out through an increased occurrence of dust events, potentially resulting from a relative increase in meridional flow and/or dry conditions over the Mediterranean.

scholarly journals History of desert dust deposition recorded in the Elbrus ice core

2019 ◽  
Author(s):  
Stanislav Kutuzov ◽  
Michel Legrand ◽  
Suzanne Preunkert ◽  
Patrick Ginot ◽  
Vladimir Mikhalenko ◽  
...  
Keyword(s):  
North Africa ◽  
Drought Index ◽  
Decadal Variability ◽  
Ice Core ◽  
Ice Cores ◽  
Dust Deposition ◽  
The Past ◽  
Dust Sources ◽  
Increasing Trend ◽  
History Of

Abstract. Ice cores are one of the most valuable paleo-archives. Records from the ice cores can provide information not only about the amount of dust in the atmosphere but also about dust sources and its changes in the past. A 182 m long ice core has been recovered at the western plateau of Mt. Elbrus (5115 m elevation) in 2009. This record was extended with the shallow ice core drilling in 2013. Here we present analysis of the concentrations of Ca2+, a commonly used proxy of dust, recorded in Elbrus ice core over the period 1774–2013. The calcium record reveals a quasi decadal variability with a general increasing trend. Using multiple regression analysis we found a statistically significant spatial correlation of the Elbrus Ca2+ summer concentrations and precipitation and soil moisture content in Levant region (specifically Syria and Iraq). The Ca2+ record also correlates with drought index in North Africa (r = 0.69 p 

scholarly journals 1000 year ice-core records from Berkner Island, Antarctica

2002 ◽  
Vol 35 ◽  
pp. 45-51 ◽  
Author(s):  
Robert Mulvaney ◽  
Hans Oerter ◽  
David A. Peel ◽  
Wolfgang Graf ◽  
Carol Arrowsmith ◽  
...  
Keyword(s):  
Decadal Variability ◽  
Ice Core ◽  
Ice Cores ◽  
Aerosol Deposition ◽  
Climate History ◽  
Joint Project ◽  
The Past ◽  
Annual Layer ◽  
History Of ◽  
Field Season

AbstractTwo medium-depth ice cores were retrieved from Berkner Island by a joint project between the Alfred-Wegener-Institut and the British Antarctic Survey in the 1994/95 field season. A 151m deep core from the northern dome (Reinwarthhöhe) of Berkner Island spans 700 years, while a 181 m deep core from the southern dome (Thyssenhöhe) spans approximately 1200 years. Both cores display clear seasonal cycles in electrical conductivity measurements, allowing dating by annual-layer counting and the calculation of accumulation profiles. Stable-isotope measurements (both δ18O and δD), together with the accumulation data, allow us to estimate changes in climate for most of the past millennium: the data show multi-decadal variability around a generally stable long-termmean. In addition, a full suite of major chemistry measurements is available to define the history of aerosol deposition at these sites: again, there is little evidence that the chemistry of the sites has changed over the past six centuries. Finally, we suggest that the southern dome, with an ice thickness of 950 m, is an ideal site from which to gain a climate history of the late stages of the last glacial and the deglaciation for comparison with the records from the deep Antarctic ice cores, and with other intermediate-depth cores such as Taylor Dome and Siple Dome.

Microfluidic device for continuous-flow analysis of organics in oldest ice

2020 ◽  
Author(s):  
Daniele FIlippi ◽  
Chiara Giorio
Keyword(s):  
Time Resolution ◽  
Ice Core ◽  
Flow Analysis ◽  
Ice Cores ◽  
Core Sample ◽  
High Time ◽  
High Time Resolution ◽  
Continuous Analysis ◽  
Climate History ◽  
History Of

&lt;p&gt;The Beyond EPICA Oldest Ice (BEOI) project will drill an ice core dating back to 1.5 million-years (1.5 Myr) ago. This ice core is of particular interest to the scientific community as it will be the only one covering the climate history of the Mid Pleistocene Transition, when glacial-interglacial cycles changed from a 40 Kyr to 100 Kyr cyclicity, and for which causes are not well understood currently. Obtaining useful climatic information beyond 800 Kyr represents an analytical challenge due to the fact that the deepest section of the ice core is very compact and the amount of sample available is very low.&lt;/p&gt;&lt;p&gt;Current analytical methods for the determination of organics in ice are characterized by a large number of steps that requires large amounts of sample for a single analysis. This results in the loss of the high time resolution desired from ice cores which is particularly problematic for deeper (i.e. older) records where the ice is more compact.&lt;/p&gt;&lt;p&gt;This work aims at combining the growing field of microfluidics with improvements to conventional mass spectrometry to allow for continuous analysis of organics in ice cores, melted in continuous on a melting-head. In fact, microfluidic is a powerful technology in which, only a small amount of liquid (10&lt;sup&gt;-9&lt;/sup&gt;-10&lt;sup&gt;-18&lt;/sup&gt; liters) is manipulated and controlled with an extremely high precision. The method invokes a three-step process: (1) the melted ice core sample is sent to a nebulizer to produce aerosol, then (2) the aerosol is dried to remove water content and concentrate the sample, and (3) the aerosol is sent to a mass spectrometer for continuous analysis through a modified electrospray ionization (ESI) probe.&lt;/p&gt;&lt;p&gt;This novel system, once operational, can be applied to a range of ice cores but is especially useful for older ice cores given the stratification of deeper segments. It will allow the research community to measure organic compounds with a high time resolution, even in the oldest of ice, to retrieve paleoclimatic information that would otherwise be lost using traditional methods.&lt;/p&gt;

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