How does sea ice influence &amp;lt;i&amp;gt;δ&amp;lt;/i&amp;gt;&amp;lt;sup&amp;gt;18&amp;lt;/sup&amp;gt;O of Arctic precipitation?

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

doi:10.5194/acp-17-5865-2017

How does sea ice influence &lt;i&gt;δ&lt;/i&gt;&lt;sup&gt;18&lt;/sup&gt;O of Arctic precipitation?

Anne-Katrine Faber, Rasmus Anker Pedersen + Show 2 more

Open Access

https://doi.org/10.5194/acp-17-5865-2017

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Abstract

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.

Highlights

Records of stable water isotopologues from polar ice cores have been widely used to reconstruct past climate variability
The aim of this study was to investigate whether changes in sea ice and sea surface temperature (SST) derived from observed anomalies can influence the isotopic composition of precipitation in the Arctic
Results are presented from isoCAM3 an isotope-equipped atmospheric general circulation model (AGCM), forced with different distributions of Arctic sea ice changes and associated SST from the ERA-interim reanalysis product

Summary

Introduction

Records of stable water isotopologues from polar ice cores have been widely used to reconstruct past climate variability. It has become clear that the isotopic composition of precipitation is a complex signal, influenced by both local and regional climate conditions (Vinther et al, 2010; Steen-Larsen et al, 2011; Sjolte et al, 2011; Sodemann et al, 2008b; White et al, 1997; Johnsen et al, 1989). The isotopic composition of the precipitation is an integrated signal of the conditions along the moisture transport pathway from source to deposition. Variations in local Greenland temperatures, conditions at source regions and atmospheric circulation all influence the isotopic composition of Greenland precipitation (SteenLarsen et al, 2011; Bonne et al, 2014; Sodemann et al, 2008a, b; Sjolte et al, 2011; Vinther et al, 2010)

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