Clumped isotope constraints on upper tropospheric temperature changes during the last deglaciation ...

• Main Authors: Banerjee, Asmita, Yeung, Laurence, Yan, Yuzhen
• Format: Conference Object
• Language: unknown
• Published: GFZ German Research Centre for Geosciences 2023
• Subjects: Antarctic; West Antarctic Ice Sheet; Antarc*; ice core; Ice Sheet
• Online Access: https://dx.doi.org/10.57757/iugg23-2473; https://gfzpublic.gfz-potsdam.de/pubman/item/item_5018279

<!--!introduction!--> 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 ... : The 28th IUGG General Assembly (IUGG2023) (Berlin 2023) ...