New insights into Southern Hemisphere temperature changes from Vostok ice cores using deuterium excess correction

2002 ◽  
Vol 203 (3-4) ◽  
pp. 829-843 ◽  
Author(s):  
Françoise Vimeux ◽  
Kurt M. Cuffey ◽  
Jean Jouzel
Keyword(s):  
Southern Hemisphere ◽  
Ice Cores ◽  
Deuterium Excess ◽  
Temperature Changes ◽  
Hemisphere Temperature

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.

scholarly journals Ranges of moisture-source temperature estimated from Antarctic ice cores stable isotope records over glacial–interglacial cycles

2012 ◽  
Vol 8 (3) ◽  
pp. 1109-1125 ◽  
Author(s):  
R. Uemura ◽  
V. Masson-Delmotte ◽  
J. Jouzel ◽  
A. Landais ◽  
H. Motoyama ◽  
...  
Keyword(s):  
Air Temperature ◽  
Ice Core ◽  
Ice Cores ◽  
Regression Equations ◽  
Temperature Changes ◽  
Source Temperature ◽  
Moisture Source ◽  
Isotopic Model ◽  
Temperature Proxy ◽  
Coefficient Of Regression

Abstract. A single isotope ratio (δD or δ18O) of water is widely used as an air-temperature proxy in Antarctic ice core records. These isotope ratios, however, do not solely depend on air-temperature but also on the extent of distillation of heavy isotopes out of atmospheric water vapor from an oceanic moisture source to a precipitation site. The temperature changes at the oceanic moisture source (Δ Tsource) and at the precipitation site (Δ Tsite) can be retrieved by using deuterium-excess (d) data. A new d record from Dome Fuji, Antarctica spanning the past 360 000 yr is presented and compared with records from Vostok and EPICA Dome C ice cores. In previous studies, to retrieve Δ Tsource and Δ Tsite information, different linear regression equations were proposed using theoretical isotope distillation models. A major source of uncertainty lies in the coefficient of regression, βsite which is related to the sensitivity of d to Δ Tsite. We show that different ranges of temperature and selections of isotopic model outputs may increase the value of βsite by more than a factor of two. To explore the impacts of this coefficient on reconstructed temperatures, we apply for the first time the exact same methodology to the isotope records from the three Antarctica ice cores. We show that uncertainties in the βsite coefficient strongly affect (i) the glacial–interglacial magnitude of Δ Tsource; (ii) the imprint of obliquity in Δ Tsource and in the site-source temperature gradient. By contrast, we highlight the robustness of Δ Tsite reconstruction using water isotopes records.

On the relationship between stable isotopes and major impurity species as inferred from a two-dimensional firn sampling approach at EDML, East Antarctica

2021 ◽  
Author(s):  
Thomas Münch ◽  
Maria Hörhold ◽  
Johannes Freitag ◽  
Melanie Behrens ◽  
Thomas Laepple
Keyword(s):  
Isotopic Composition ◽  
Interannual Variability ◽  
Ice Core ◽  
Ice Cores ◽  
Temperature Changes ◽  
Impurity Species ◽  
Intermittent Precipitation ◽  
Ice Core Record ◽  
Stable Oxygen ◽  
Atmospheric Variations

<p>Ice cores constitute a major palaeoclimate archive by recording, among many others, the atmospheric variations of stable oxygen and hydrogen isotopic composition of water and of soluble ionic impurities. While impurities are used as proxies for, e.g., variations in sea ice, marine biological activity and volcanism, stable isotope records are the main source of information for the reconstruction of polar temperature changes.</p><p>However, such reconstruction efforts are complicated by the fact that temperature is by far not the only driver of isotopic composition changes. A single isotopic ice-core record will comprise variations caused by a multitude of processes, from variable atmospheric circulation and moisture pathways to the intermittency of precipitation and finally to the mixing and re-location of surface snow by wind drift (stratigraphic noise). Under the assumption that specific trace components are originally deposited with the precipitated snow and its isotopic composition, the retrieved impurity records should display a similar spatial and seasonal to interannual variability as the isotope records, caused by local stratigraphic noise as well as the time-variable and intermittent precipitation patterns, respectively.</p><p>In this contribution, we investigate the possible relationship between isotope and impurity data at the East Antarctic low-accumulation site EDML. We sampled and analysed isotopic composition and major impurity species on a four metre deep and 50 metre long trench. This enables us (1) to study the spatial (horizontal times vertical) relationship in the data, and (2) to analyse and compare the seasonal and interannual variability after removing the strong contribution of local stratigraphic noise. By this, the study improves our understanding of the depositional mechanisms that play an important role for the formation of ice-core records, and it offers to investigate the potential of using impurities to correct isotopic variability in order to improve temperature reconstructions.</p>

scholarly journals Holocene temperature variations inferred from Antarctic ice cores

1994 ◽  
Vol 20 ◽  
pp. 427-436 ◽  
Author(s):  
P. Ciais ◽  
J. Jouzel ◽  
J. R. Petit ◽  
V. Lipenkov ◽  
J. W. C. White
Keyword(s):  
Late Holocene ◽  
Ice Core ◽  
Ice Cores ◽  
Temperature Fluctuations ◽  
Base Line ◽  
Temperature Changes ◽  
Average Temperature ◽  
The Past ◽  
Reconstructed Temperature ◽  
Line Temperature

We have reconstructed temperature changes over the past 15 000 years from ice-core data in Antarctica. We used measurements of the D/H isotope ratio in ice as a proxy of temperature for central sites (Vostok, Dome C and Komsomolskaya; as well as coastal sites (D47, D15 and D10). First, we examined the dating of each core and built up a common temporal framework for the ensemble of the data. Secondly, we addressed the problem of inferring small-amplitude temperature fluctuations from the isotope data, in the light of noise-generating mechanisms involved in snow deposition. Temperature was reconstructed so as to minimize distortion created by the sampling of ice cores in the field. The seven ice cores studied yield an average temperature curve which can be put in perspective with nearby paleoclimatic records. The early Holocene experienced climates warmer than today by 1-2°C. The late Holocene period shows more discernible, shorter-duration, temperature fluctuations, superimposed on a fairly stable "base-line" temperature.

scholarly journals Isotope Climatic Record Over The Last 2.5 KA from Dome C, Antarctica, Ice cores

1982 ◽  
Vol 3 ◽  
pp. 17-22 ◽  
Author(s):  
J. P. Benoist ◽  
J. Jouzel ◽  
C. Lorius ◽  
L. Merlivat ◽  
M. Pourchet
Keyword(s):  
Isotope Composition ◽  
Accumulation Rate ◽  
Maximum Amplitude ◽  
Ice Cores ◽  
Ice Age ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Temperature Changes ◽  
Low Pass ◽  
Climatic Record

Data on climatic changes over thousands of years is needed for a better understanding of the shorter term variations which are of interest to man. For this purpose we measured the isotope composition (δD‰) of two adjacent ice cores drilled in the Dome C area. The time scale was established using the remarkably constant mean annual accumulation rate (37 kg m−2) determined by various techniques. The detailed isotope records were smoothed to filter out the δ value fluctuations not directly related to local temperature changes. With respect to conditions over the last 2.5 ka, the combined smoothed δ curve indicates a cooler climate from about 1800 to 1200 AD and a slightly warmer period from about 1200 to 700 AD. These periods may well correspond to the suggested world-wide Little Ice Age and medieval warm phase. Using the present δD‰/T°C measured at the surface, the maximum amplitude for these two periods, after smoothing with a low pass filter of 512 a, is approximately -0.35 and +0.3°C, respectively.

scholarly journals Vostok, Antarctica, Ice Core: The Dust Record Over The Last Climatic Cycle (∼160 ka) (Abstract)

1988 ◽  
Vol 11 ◽  
pp. 204-204
Author(s):  
L. Mounier ◽  
J. R. Petit ◽  
J. Jouzel ◽  
C. Lorius ◽  
Ye. S. Korotkevich ◽  
...  
Keyword(s):  
Total Concentration ◽  
Ice Core ◽  
Ice Cores ◽  
Optical Microscope ◽  
Ice Age ◽  
Maximum Temperature ◽  
Temperature Changes ◽  
Last Glacial ◽  
Chemical Measurements ◽  
The Last Glacial

The 2083 m Vostok Antarctic ice core provides a unique opportunity for access to many paleoclimatic and paleo-environmental proxy data. This core, which has been dated by using a glaciological model, fully covers the last glacial-interglacial cycle, and goes back to the ice age which preceded the last interglaciai (−160 ka B P ).A continuous deuterium record is now available and we have interpreted it in terms of local temperature changes. This record is dominated by the large 100 ka glacial-inter-glacial oscillation, with a maximum temperature amplitude of about 11°C; the long Last Glacial period is very well documented and it is confirmed that the warmest part of the Last Interglaciai period was about 2°C warmer than the Holocene. Comparison with the ice-volume marine record shows that the Vostok climate record is of relatively large geographical significance, which makes it possible to establish, over the last 160 ka, the link between worldwide climatic changes and the Vostok dust record that we present here.This dust content corresponds to the non-soluble microparticles. It was obtained on a discontinuous basis (1 sample = about ∼10 m). Due to the very low concentration of some samples (down to 20 x 10−9gg−1) and cracks in the ice from the first 1000 m depth, we used stringent decontamination procedures. Size distribution and total concentration were measured, using a Coulter counter and an optical microscope; the results were tested against chemical measurements (aluminium concentration). In previous studies, it has been shown that the main proportion of insoluble microparticles is of terrigenous origin and represents the small-sized (radius <2 μm) dust produced on the continents.The Vostok record displays an increase in dust concentration of up to 20 times during the coldest climatic periods, coupled with the presence of larger particles. It confirms, on a much longer time-scale, a characteristic previously noted in Antarctic and Greenland ice cores over the Last Glacial Maximum. This large increase is attributed to a greater areal extent of global tropical aridity during the cold periods, coupled with higher efficiency of atmospheric circulation in respect of dust production and transport. Beyond this, the relationship between the dust input and the successive stages during the Last Glacial is now very well documented and will be discussed with a view to correlating the Vostok climatic record with other marine and terrestrial paleodata.

scholarly journals Phase relationships between Antarctic and Greenland climate records

2002 ◽  
Vol 35 ◽  
pp. 451-456 ◽  
Author(s):  
Eric J. Steig ◽  
Richard B. Alley
Keyword(s):  
Southern Hemisphere ◽  
Climate Models ◽  
Phase Relationship ◽  
Ice Cores ◽  
Phase Lag ◽  
The North ◽  
Climate Records ◽  
Climate Time Series ◽  
Different Characteristics ◽  
Phase Relationships

AbstractComparison of climate records from Antarctic and Greenland ice cores shows that the two regions respond asynchronously during millennial-scale climate changes. the apparent out-of-phase relationship between the records has been described as a climate ``seesaw’’ in which cooling in the Northern Hemisphere is balanced by warming in the Southern Hemisphere. the same relationship has also been attributed to the initiation of climate-change events in the Southern Hemisphere, rather than the North Atlantic as is conventionally assumed. A simple statistical approach−band-pass filtering combined with lag–correlation tests−used to examine the phase relationships in more detail shows that neither an anti-phase nor a phase-lag relationship adequately describes the observations. Whereas Antarctic and Greenland climate records do exhibit approximate anti-phase behavior about 50% of the time, they are generally in phase during cooling. A phase lead of Southern Hemisphere climate of 1000–1600 years is statistically indistinguishable from a lag of 400–800 years, whether for Dansgaard–Oeschger, Heinrich or longer-duration events. the ``seesaw’’ or ``Southern lead’’ appearance of the data arises from the fundamentally different characteristics of the climate time series, most importantly the absence of rapid warming events in Antarctica comparable to those in Greenland. to be consistent with the observations, climate models will need to capture these characteristics, in addition to reproducing the correct phase relationships.

Late-Glacial and Holocene Glacier Fluctuations and Environmental Change on South Georgia, Southern Ocean

1989 ◽  
Vol 31 (2) ◽  
pp. 210-228 ◽  
Author(s):  
Chalmers M. Clapperton ◽  
David E. Sugden ◽  
Jacqueline Birnie ◽  
Mandy J. Wilson
Keyword(s):  
Environmental Change ◽  
Ice Cores ◽  
Late Glacial ◽  
Environmental Indicators ◽  
Temperature Changes ◽  
South Georgia ◽  
Ice Cap ◽  
Late Glacial And Holocene ◽  
Climatic Cooling ◽  
The Antarctic

AbstractSouth Georgia provides a terrestrial record of postglacial environmental change from a largely oceanic zone of the Earth. The record is representative of the southern westerlies and provides a link between Antarctica and the temperate zones of southern South America. Evidence from glacial geomorphology, slope stratigraphy, and analyses of environmental indicators in peat and lake cores is used to interpret this record. Wastage of the full-glacial ice cap was interrupted by a late-glacial stade of the outlet and valley glaciers before ca. 10,000 yr B.P. Plant growth had begun at low altitude (<50 m) on the sheltered (lee side) northeast coast within the late-glacial moraine limits by 9700 yr B.P. Environmental conditions on slopes above 80 m probably were too rigorous for a stable vegetation cover until ca. 6400 yr B.P. This was followed by a period from 5600 to 4800 yr B.P. when conditions were warmer than at present by up to 0.6°C. Periods of climatic cooling occurred at ca. 4800-3800 yr B.P., ca. 3400-1800 yr B.P., and within the last 1400 yr. The most extensive Holocene advance of South Georgia glaciers culminated just before 2200 yr B.P. These Holocene temperature changes of between 0.5 and 1.0°C are comparable in scale and timing to those identified from recent analyses of Vostok ice cores from the Antarctic ice sheet.

Millennial-scale climate changes on South Georgia, Southern Ocean

2003 ◽  
Vol 59 (3) ◽  
pp. 470-475 ◽  
Author(s):  
Gunhild C. Rosqvist ◽  
Pernilla Schuber
Keyword(s):  
Southern Hemisphere ◽  
North Atlantic ◽  
Climate Changes ◽  
South Atlantic ◽  
The South ◽  
Temperature Changes ◽  
South Georgia ◽  
The North ◽  
Suitable Site ◽  
Millennial Scale

AbstractThe location of South Georgia (54°S, 36°W) makes it a suitable site for the study of the climatic connections between temperate and polar environments in the Southern Hemisphere. Because the mass balance of the small cirque glaciers on South Georgia primarily responds to changes in summer temperature they can provide records of changes in the South Atlantic Ocean and atmospheric circulation. We use grey scale density, weight-loss-on-ignition, and grain size analyses to show that the proportion of glacially eroded sediments to organic sediments in Block Lake was highly variable during the last 7400 cal yr B.P. We expect that the glacial signal is clearly detectable above noise originating from nonglacial processes and assume that an increase in glacigenic sediment deposition in Block Lake has followed Holocene glacier advances. We interpret proglacial lake sediment sequences in terms of summer climate warming and cooling events. Prominent millennial-scale features include cooling events between 7200 and 7000, 5200 and 4400, and 2400 and 1600 cal yr B.P. and after 1000 cal yr B.P. Comparison with other terrestrial and marine records reveals that the South Georgian record captures all the important changes in Southern Hemisphere Holocene climate. Our results reveal a tentative coupling between climate changes in the South Atlantic and North Atlantic because the documented temperature changes on South Georgia are anti-phased to those in the North Atlantic.

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