Ice cores are exceptional archives which allow us
to reconstruct a wealth of climatic parameters ... more Ice cores are exceptional archives which allow us to reconstruct a wealth of climatic parameters as well as past atmospheric composition over the last 800 kyr in Antarctica. Inferring the variations in past accumulation rate in polar regions is essential both for documenting past climate and for ice core chronology. On the East Antarctic Plateau, the accumulation rate is so small that annual layers cannot be identified and accumulation rate is mainly deduced from the water isotopic composition assuming constant temporal re- lationships between temperature, water isotopic composition and accumulation rate. Such an assumption leads to large un- certainties on the reconstructed past accumulation rate. Here, we use high-resolution beryllium-10 (10Be) as an alternative tool for inferring past accumulation rate for the EPICA Dome C ice core, in East Antarctica. We present a high-resolution 10Be record covering a full climatic cycle over the period 269 to 355 ka from Marine Isotope Stage (MIS) 9 to 10, includ- ing a period warmer than pre-industrial (MIS 9.3 optimum). After correcting 10Be for the estimated effect of the palaeo- magnetic field, we deduce that the 10Be reconstruction is in reasonably good agreement with EDC3 values for the full cycle except for the period warmer than present. For the lat- ter, the accumulation is up to 13 % larger (4.46 cm ie yr−1 instead of 3.95). This result is in agreement with the studies suggesting an underestimation of the deuterium-based accu- mulation for the optimum of the Holocene (Parrenin et al., 2007a). Using the relationship between accumulation rate and surface temperature from the saturation vapour relation- ship, the 10Be-based accumulation rate reconstruction sug- gests that the temperature increase between the MIS 9.3 opti- mum and present day may be 2.4 K warmer than estimated by the water isotopes reconstruction. We compare these recon- structions to the available model results from CMIP5-PMIP3 for a glacial and an interglacial state, i.e. for the Last Glacial Maximum and pre-industrial climates. While 3 out of 7 mod- els show relatively good agreement with the reconstructions of the accumulation–temperature relationships based on 10Be and water isotopes, the other models either underestimate or overestimate it, resulting in a range of model results much larger than the range of the reconstructions. Indeed, the models can encounter some difficulties in simulating precipitation changes linked with temperature or water isotope content on the East Antarctic Plateau during glacial–interglacial transition and need to be improved in the future.
Ice cores are exceptional archives which allow us
to reconstruct a wealth of climatic parameters ... more Ice cores are exceptional archives which allow us to reconstruct a wealth of climatic parameters as well as past atmospheric composition over the last 800 kyr in Antarctica. Inferring the variations in past accumulation rate in polar regions is essential both for documenting past climate and for ice core chronology. On the East Antarctic Plateau, the accumulation rate is so small that annual layers cannot be identified and accumulation rate is mainly deduced from the water isotopic composition assuming constant temporal re- lationships between temperature, water isotopic composition and accumulation rate. Such an assumption leads to large un- certainties on the reconstructed past accumulation rate. Here, we use high-resolution beryllium-10 (10Be) as an alternative tool for inferring past accumulation rate for the EPICA Dome C ice core, in East Antarctica. We present a high-resolution 10Be record covering a full climatic cycle over the period 269 to 355 ka from Marine Isotope Stage (MIS) 9 to 10, includ- ing a period warmer than pre-industrial (MIS 9.3 optimum). After correcting 10Be for the estimated effect of the palaeo- magnetic field, we deduce that the 10Be reconstruction is in reasonably good agreement with EDC3 values for the full cycle except for the period warmer than present. For the lat- ter, the accumulation is up to 13 % larger (4.46 cm ie yr−1 instead of 3.95). This result is in agreement with the studies suggesting an underestimation of the deuterium-based accu- mulation for the optimum of the Holocene (Parrenin et al., 2007a). Using the relationship between accumulation rate and surface temperature from the saturation vapour relation- ship, the 10Be-based accumulation rate reconstruction sug- gests that the temperature increase between the MIS 9.3 opti- mum and present day may be 2.4 K warmer than estimated by the water isotopes reconstruction. We compare these recon- structions to the available model results from CMIP5-PMIP3 for a glacial and an interglacial state, i.e. for the Last Glacial Maximum and pre-industrial climates. While 3 out of 7 mod- els show relatively good agreement with the reconstructions of the accumulation–temperature relationships based on 10Be and water isotopes, the other models either underestimate or overestimate it, resulting in a range of model results much larger than the range of the reconstructions. Indeed, the models can encounter some difficulties in simulating precipitation changes linked with temperature or water isotope content on the East Antarctic Plateau during glacial–interglacial transition and need to be improved in the future.
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to reconstruct a wealth of climatic parameters as well as past
atmospheric composition over the last 800 kyr in Antarctica.
Inferring the variations in past accumulation rate in polar
regions is essential both for documenting past climate and
for ice core chronology. On the East Antarctic Plateau, the
accumulation rate is so small that annual layers cannot be
identified and accumulation rate is mainly deduced from the
water isotopic composition assuming constant temporal re-
lationships between temperature, water isotopic composition
and accumulation rate. Such an assumption leads to large un-
certainties on the reconstructed past accumulation rate. Here,
we use high-resolution beryllium-10 (10Be) as an alternative
tool for inferring past accumulation rate for the EPICA Dome
C ice core, in East Antarctica. We present a high-resolution
10Be record covering a full climatic cycle over the period 269
to 355 ka from Marine Isotope Stage (MIS) 9 to 10, includ-
ing a period warmer than pre-industrial (MIS 9.3 optimum).
After correcting 10Be for the estimated effect of the palaeo-
magnetic field, we deduce that the 10Be reconstruction is in
reasonably good agreement with EDC3 values for the full
cycle except for the period warmer than present. For the lat-
ter, the accumulation is up to 13 % larger (4.46 cm ie yr−1
instead of 3.95). This result is in agreement with the studies
suggesting an underestimation of the deuterium-based accu-
mulation for the optimum of the Holocene (Parrenin et al.,
2007a). Using the relationship between accumulation rate
and surface temperature from the saturation vapour relation-
ship, the 10Be-based accumulation rate reconstruction sug-
gests that the temperature increase between the MIS 9.3 opti-
mum and present day may be 2.4 K warmer than estimated by
the water isotopes reconstruction. We compare these recon-
structions to the available model results from CMIP5-PMIP3
for a glacial and an interglacial state, i.e. for the Last Glacial
Maximum and pre-industrial climates. While 3 out of 7 mod-
els show relatively good agreement with the reconstructions
of the accumulation–temperature relationships based on
10Be and water isotopes, the other models either underestimate or overestimate it, resulting in a range of model results much
larger than the range of the reconstructions. Indeed, the models can encounter some difficulties in simulating precipitation changes linked with temperature or water isotope content on the East Antarctic Plateau during glacial–interglacial transition and need to be improved in the future.
to reconstruct a wealth of climatic parameters as well as past
atmospheric composition over the last 800 kyr in Antarctica.
Inferring the variations in past accumulation rate in polar
regions is essential both for documenting past climate and
for ice core chronology. On the East Antarctic Plateau, the
accumulation rate is so small that annual layers cannot be
identified and accumulation rate is mainly deduced from the
water isotopic composition assuming constant temporal re-
lationships between temperature, water isotopic composition
and accumulation rate. Such an assumption leads to large un-
certainties on the reconstructed past accumulation rate. Here,
we use high-resolution beryllium-10 (10Be) as an alternative
tool for inferring past accumulation rate for the EPICA Dome
C ice core, in East Antarctica. We present a high-resolution
10Be record covering a full climatic cycle over the period 269
to 355 ka from Marine Isotope Stage (MIS) 9 to 10, includ-
ing a period warmer than pre-industrial (MIS 9.3 optimum).
After correcting 10Be for the estimated effect of the palaeo-
magnetic field, we deduce that the 10Be reconstruction is in
reasonably good agreement with EDC3 values for the full
cycle except for the period warmer than present. For the lat-
ter, the accumulation is up to 13 % larger (4.46 cm ie yr−1
instead of 3.95). This result is in agreement with the studies
suggesting an underestimation of the deuterium-based accu-
mulation for the optimum of the Holocene (Parrenin et al.,
2007a). Using the relationship between accumulation rate
and surface temperature from the saturation vapour relation-
ship, the 10Be-based accumulation rate reconstruction sug-
gests that the temperature increase between the MIS 9.3 opti-
mum and present day may be 2.4 K warmer than estimated by
the water isotopes reconstruction. We compare these recon-
structions to the available model results from CMIP5-PMIP3
for a glacial and an interglacial state, i.e. for the Last Glacial
Maximum and pre-industrial climates. While 3 out of 7 mod-
els show relatively good agreement with the reconstructions
of the accumulation–temperature relationships based on
10Be and water isotopes, the other models either underestimate or overestimate it, resulting in a range of model results much
larger than the range of the reconstructions. Indeed, the models can encounter some difficulties in simulating precipitation changes linked with temperature or water isotope content on the East Antarctic Plateau during glacial–interglacial transition and need to be improved in the future.