Regional climate signal vs. local noise: a two-dimensional view
of water isotopes in Antarctic firn at Kohnen Station, Dronning Maud
Land

Münch, Thomas; Kipfstuhl, Sepp; Freitag, Johannes; Meyer, Hanno; Laepple, Thomas

doi:10.5194/cp-12-1565-2016

Cited by 64 publications

(92 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Still, on the East Antarctic Plateau, a significant seasonal cycle is depicted in the isotopic composition of the precipitation (Fujita and Abe, 2006;Landais et al, 2012;Stenni et al, 2016) and of the surface snow (Touzeau et al, 2016). So far, whether this seasonal cycle is archived or not in buried snow, and thus, whether stacking an array of snow pits permits to increase the signal to noise ratio and depict a climatic record at the seasonal scale from water isotopic signal remain unclear (Ekaykin et al, 2014;Altnau et al, 2015;Münch et al, 2016). 20 Several studies have focused on understanding how is the climatic signal archived in the isotopic composition of snow and ice on the East Antarctic Plateau.…”

Section: Introductionmentioning

confidence: 99%

Archival of the water stable isotope signal in East Antarctic ice cores

Casado

Landais

Picard

et al. 2016

Preprint

Self Cite

View full text Add to dashboard Cite

Abstract. The oldest ice core records are obtained from the East Antarctic plateau. Water stable isotopes records are key for reconstructions of past climatic conditions both over the ice sheet and at the evaporation source. The accuracy of such climate reconstructions crucially depends on the knowledge of all the processes affecting the water vapour, precipitation and snow isotopic composition. Atmospheric fractionation processes are well understood and can be integrated in Rayleigh distillation and complex isotope enabled climate models. However, a comprehensive quantitative understanding of processes potentially 5 altering the snow isotopic composition after the deposition is still missing, especially for exchanges between vapour and snow.In low accumulation sites such as found on the East Antarctic Plateau, these poorly constrained processes are especially likely to play a significant role. This limits the interpretation of isotopic composition from ice core records, specifically at short time scales. 10Here, we combine observations of isotopic composition in the vapour, the precipitation, the surface snow and the buried snow from various sites of the East Antarctic Plateau. At the seasonal scale, we highlight a significant impact of metamorphism on surface snow isotopic signal compared to the initial precipitation isotopic signal. In particular, in summer, exchanges of water molecules between vapour and snow are driven by the sublimation/condensation cycles at the diurnal scale. Using highly resolved isotopic composition profiles from pits in five East Antarctic sites, we identify a common 20 cm cycle which 15 cannot be attributed to the seasonal variability of precipitation. Altogether, the smaller range of isotopic compositions observed in the buried and in the surface snow compared to the precipitation, and also the reduced slope between surface snow isotopic composition and temperature compared to precipitation, constitute evidences of post-deposition processes affecting the variability of the isotopic composition in the snow pack. To reproduce these processes in snow-models is crucial to understand the link between snow isotopic composition and climatic conditions and to improve the interpretation of isotopic composition as a 20 paleoclimate proxy.

show abstract

Section: Introductionmentioning

confidence: 99%

Archival of the water stable isotope signal in East Antarctic ice cores

Casado

Landais

Picard

et al. 2016

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…Seasonal variations are also imprinted in the snow isotopic composition of high accumulation sites in coastal areas of Antarctica (Morgan, 1985;Masson-Delmotte et al, 2003;Küttel et al, 2012). For low accumulation sites as found on the East Antarctic Plateau, there is no consensus whether ice core records can reveal the climatic signal at resolutions finer than multidecadal (Baroni et al, 2011) or not (Ekaykin et al, 2002;Pol et al, 2014;Münch et al, 2016). Ekaykin et al (2002) analysed multiple pits from Vostok and identified large spatio-temporal variations caused by post-deposition processes 15 associated with surface topography and wind interactions.…”

Section: Introductionmentioning

confidence: 99%

“…Still, on the East Antarctic Plateau, a clear seasonal cycle is depicted in the isotopic composition of the precipitation (Fujita and Abe, 2006;Landais et al, 2012;Stenni et al, 2016) and of the surface snow (Touzeau et al, 2016). So far, whether this seasonal cycle is archived or not in buried snow, and thus, whether stacking an array of snow pits enables us to increase the signal to 20 noise ratio and depict a climatic record at the seasonal scale from water isotopic signal is an important open question (Ekaykin et al, 2014;Altnau et al, 2015;Münch et al, 2016Münch et al, , 2017.…”

Section: Introductionmentioning

confidence: 99%

“…It is important to note that the protocol of surface snow sampling from the PRE-REC campaign differs greatly from the protocols from the NIVO and SUNITEDC programs due to the presence of the wood plate. In addition to the Dome C snow pits, two new isotopic composition profiles from Kohnen were extracted from trenches, following the methodology reported in Münch et al (2016) but up to a depth of 3.6 m and a vertical resolution of 3 cm. Both profiles are separated by approximately 500 m well beyond the decorrelation scale of the stratigraphic noise, to enable eval-…”

mentioning

confidence: 99%

See 1 more Smart Citation

Archival processes of the water stable isotope signal in East Antarctic ice cores

Casado¹,

Landais²,

Picard³

et al. 2017

Preprint

Self Cite

View full text Add to dashboard Cite

Abstract. The oldest ice core records are obtained from the East Antarctic plateau. Water isotopes records are key to reconstructing past climatic conditions over the ice sheet and at the evaporation source. The accuracy of climate reconstructions depends on knowledge of all the processes affecting water vapour, precipitation and snow isotopic compositions. Fractionation processes are well understood and can be integrated in Rayleigh distillation and isotope enabled climate models. However, a quantitative understanding of processes potentially altering the snow isotopic composition after the deposition is still missing. 5In low accumulation sites, such as those found in Antarctica, these poorly constrained processes are likely to play a significant role and limit the interpretation of isotopic composition.Here, we combine observations of isotopic composition in the vapour, the precipitation, the surface snow and the buried snow from Dome C, a deep ice core site on the East Antarctic Plateau. At the seasonal scale, we suggest a significant impact of 10 metamorphism on surface snow isotopic signal compared to the initial precipitation signal. Particularly, in summer, exchanges of water molecules between vapour and snow are driven by the sublimation/condensation cycles at the diurnal scale. Using highly resolved isotopic composition profiles from pits in five Antarctic sites, we identify common patterns, despite different accumulation rates, which cannot be attributed to the seasonal variability of precipitation. Altogether, the difference in the signals observed in the precipitation, surface snow and buried snow isotopic composition constitute evidences of post-deposition 15 processes affecting ice core records in low accumulation areas. 1The Cryosphere Discuss., https://doi

show abstract

“…Hence, the initial precipitation signal is modified by local post-deposition processes (Ekaykin et al 2002) due to snow-air interactions, such as the impact of metamorphism, wind and surface roughness, and diffusion. It prevents proper recording of the signal at the intra-seasonal and seasonal scale for sites with accumulation lower than 8 cm ice equivalent per year (Münch et al 2016).…”

Section: Resolution and Noisementioning

confidence: 99%