Articles | Volume 17, issue 9
https://doi.org/10.5194/acp-17-5865-2017
https://doi.org/10.5194/acp-17-5865-2017
Research article
 | 
12 May 2017
Research article |  | 12 May 2017

How does sea ice influence δ18O of Arctic precipitation?

Anne-Katrine Faber, Bo Møllesøe Vinther, Jesper Sjolte, and Rasmus Anker Pedersen

Abstract. This study investigates how variations in Arctic sea ice and sea surface conditions influence δ18O of present-day Arctic precipitation. This is done using the model isoCAM3, an isotope-equipped version of the National Center for Atmospheric Research Community Atmosphere Model version 3. Four sensitivity experiments and one control simulation are performed with prescribed sea surface temperature (SST) and sea ice. Each of the four experiments simulates the atmospheric and isotopic response to Arctic oceanic conditions for selected years after the beginning of the satellite era in 1979.

Changes in sea ice extent and SSTs have different impacts in Greenland and the rest of the Arctic. The simulated changes in central Arctic sea ice do not influence δ18O of Greenland precipitation, only anomalies of Baffin Bay sea ice. However, this does not exclude the fact that simulations based on other sea ice and sea surface temperature distributions might yield changes in the δ18O of precipitation in Greenland. For the Arctic, δ18O of precipitation and water vapour is sensitive to local changes in sea ice and sea surface temperature and the changes in water vapour are surface based. Reduced sea ice extent yields more enriched isotope values, whereas increased sea ice extent yields more depleted isotope values. The distribution of the sea ice and sea surface conditions is found to be essential for the spatial distribution of the simulated changes in δ18O.

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Short summary
The recent decades loss of Arctic sea ice provide an interesting opportunity to study the impact of sea ice changes on the isotopic composition of Arctic precipitation. Using a climate model that can simulate water isotopes, we find that reduced sea ice extent yields more enriched isotope values while increased sea ice extent yields more depleted isotope values. Results also show that the spatial distribution of the sea ice extent are important.
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