Clumped isotope constraints on upper tropospheric temperature changes during the last deglaciation
The clumped-isotope composition of oxygen, denoted by Δ 36 , measures the proportional abundance of two heavy oxygen isotopes, 18 O 18 O in oxygen, and is sensitive to photochemical and thermal properties of the atmosphere. Ozone photochemistry controls Δ 36 values via isotope exchange reactions, yi...
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ftgfzpotsdam:oai:gfzpublic.gfz-potsdam.de:item_5018279 2023-10-01T03:52:10+02:00 Clumped isotope constraints on upper tropospheric temperature changes during the last deglaciation Banerjee, A. Yeung, L. Yan, Y. 2023 https://gfzpublic.gfz-potsdam.de/pubman/item/item_5018279 eng eng info:eu-repo/semantics/altIdentifier/doi/10.57757/IUGG23-2473 https://gfzpublic.gfz-potsdam.de/pubman/item/item_5018279 XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG) info:eu-repo/semantics/conferenceObject 2023 ftgfzpotsdam https://doi.org/10.57757/IUGG23-2473 2023-09-03T23:42:28Z The clumped-isotope composition of oxygen, denoted by Δ 36 , measures the proportional abundance of two heavy oxygen isotopes, 18 O 18 O in oxygen, and is sensitive to photochemical and thermal properties of the atmosphere. Ozone photochemistry controls Δ 36 values via isotope exchange reactions, yielding a higher abundance of 18 O 18 O than would be expected for a stochastic distribution. Colder temperatures increase this preference for 18 O 18 O formation at equilibrium by 0.013‰/K. If tropospheric ozone and stratosphere-troposphere exchange fluxes remain unchanged, Δ 36 would record changes in free-tropospheric temperatures to provide a high-resolution record of upper tropospheric (UT) temperatures on glacial-interglacial timescales. We present an ice core record of Δ 36 values measured in the West Antarctic Ice Sheet Divide ice core spanning 15–8ka BP. Measured Δ 36 values decrease to Early Holocene (EH; 8-11ka BP)/Pre-industrial (PI; 1850CE) levels at the onset of the Bølling Allerød (BA; 14.7–12.9ka BP) warm period, and continues into the Younger Dryas (YD; 12.9-11.7ka BP). Δ 36 values reach PI/EH when global-mean surface temperatures are still colder than those of PI/EH. This indicates either a change in the lapse rate feedback, or a significant increase in tropospheric ozone burden. Our investigations reveal no evidence for increased O 3 and that the decrease in Δ 36 is coeval with rapid decreases in Northern Hemisphere ice sheet elevation. Previous work highlights the influence of changing ice sheet elevation on the thermal structure of the atmosphere. A plausible explanation for our observation is that during periods of abrupt climate change the cryosphere plays a predominant role in governing UT temperatures. Conference Object Antarc* Antarctic ice core Ice Sheet GFZpublic (German Research Centre for Geosciences, Helmholtz-Zentrum Potsdam) Antarctic West Antarctic Ice Sheet |
institution |
Open Polar |
collection |
GFZpublic (German Research Centre for Geosciences, Helmholtz-Zentrum Potsdam) |
op_collection_id |
ftgfzpotsdam |
language |
English |
description |
The clumped-isotope composition of oxygen, denoted by Δ 36 , measures the proportional abundance of two heavy oxygen isotopes, 18 O 18 O in oxygen, and is sensitive to photochemical and thermal properties of the atmosphere. Ozone photochemistry controls Δ 36 values via isotope exchange reactions, yielding a higher abundance of 18 O 18 O than would be expected for a stochastic distribution. Colder temperatures increase this preference for 18 O 18 O formation at equilibrium by 0.013‰/K. If tropospheric ozone and stratosphere-troposphere exchange fluxes remain unchanged, Δ 36 would record changes in free-tropospheric temperatures to provide a high-resolution record of upper tropospheric (UT) temperatures on glacial-interglacial timescales. We present an ice core record of Δ 36 values measured in the West Antarctic Ice Sheet Divide ice core spanning 15–8ka BP. Measured Δ 36 values decrease to Early Holocene (EH; 8-11ka BP)/Pre-industrial (PI; 1850CE) levels at the onset of the Bølling Allerød (BA; 14.7–12.9ka BP) warm period, and continues into the Younger Dryas (YD; 12.9-11.7ka BP). Δ 36 values reach PI/EH when global-mean surface temperatures are still colder than those of PI/EH. This indicates either a change in the lapse rate feedback, or a significant increase in tropospheric ozone burden. Our investigations reveal no evidence for increased O 3 and that the decrease in Δ 36 is coeval with rapid decreases in Northern Hemisphere ice sheet elevation. Previous work highlights the influence of changing ice sheet elevation on the thermal structure of the atmosphere. A plausible explanation for our observation is that during periods of abrupt climate change the cryosphere plays a predominant role in governing UT temperatures. |
format |
Conference Object |
author |
Banerjee, A. Yeung, L. Yan, Y. |
spellingShingle |
Banerjee, A. Yeung, L. Yan, Y. Clumped isotope constraints on upper tropospheric temperature changes during the last deglaciation |
author_facet |
Banerjee, A. Yeung, L. Yan, Y. |
author_sort |
Banerjee, A. |
title |
Clumped isotope constraints on upper tropospheric temperature changes during the last deglaciation |
title_short |
Clumped isotope constraints on upper tropospheric temperature changes during the last deglaciation |
title_full |
Clumped isotope constraints on upper tropospheric temperature changes during the last deglaciation |
title_fullStr |
Clumped isotope constraints on upper tropospheric temperature changes during the last deglaciation |
title_full_unstemmed |
Clumped isotope constraints on upper tropospheric temperature changes during the last deglaciation |
title_sort |
clumped isotope constraints on upper tropospheric temperature changes during the last deglaciation |
publishDate |
2023 |
url |
https://gfzpublic.gfz-potsdam.de/pubman/item/item_5018279 |
geographic |
Antarctic West Antarctic Ice Sheet |
geographic_facet |
Antarctic West Antarctic Ice Sheet |
genre |
Antarc* Antarctic ice core Ice Sheet |
genre_facet |
Antarc* Antarctic ice core Ice Sheet |
op_source |
XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG) |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.57757/IUGG23-2473 https://gfzpublic.gfz-potsdam.de/pubman/item/item_5018279 |
op_doi |
https://doi.org/10.57757/IUGG23-2473 |
_version_ |
1778517871642542080 |