Spatial variability of snow isotopic composition and accumulation rate at the stake farm of Vostok station (Сentral Antarctica)

The knowledge of the spatial distribution of the snow accumulation rate and isotopic composition in different scales, from local to continental, over the Antarctic Ice Sheet is critically important for the interpretation of the paleoclimate data obtained from deep ice cores, for correct assessment of the ice sheet mass balance, etc. With this in mind, we have synthesized geodetic, glaciological and geochemical data collected in the vicinity of central Antarctic Vostok station in 1970–2017 in order to shed light on the processes governing the spatial distribution of snow isotopic composition and accumulation rate in the spatial scale from 100 to 1000 m. First, we have discovered that snow surface height and snow accumulation rate field are strongly affected by the influence of the logistic convoy route annually operating between Russian Antarctic stations Vostok and Progress. This influence is detectable up to 1 km leeward from the route. At the same time the isotopic composition of the upper 10 cm of the snow does not show any anomalies in the vicinity of the route. This is an unexpected result, because large anomalies of the ice sheet surface (e.g., megadunes) are known to affect the snow isotopic composition. Second, in the undisturbed part of the snow surface near Vostok station we have discovered quasi-periodic (with the wavelength of about 400 m) low-amplitude variations of the surface height that are covariant with the corresponding waves in snow accumulation and isotopic composition. We suggest that spatial variability of the snow isotopic composition is due to the different ratio of summer and winter precipitation deposited in different locations, as evident from a strong negative correlation between δD and dxs parameters. The results of this study may explain the nature of the low-frequency noise (with the time-scale from decades to centuries) observed in the climate records obtained from shallow and deep ice cores in central Antarctica.

1. Ekaykin A.A. Stabilnye isotopy vody i glaciologii i paleogeografii. Stable water isotopes in glaciology and palaeogeography. St. Petersburg: AARI, 2016: 63 p. [In Russian].

2. Landais A., Casado M., Prie F., Magand O., Arnaud L., Ekaykin A., Petit J.R., Picard G., Fily M., Minster B., Touzeau A., Goursaud S., Masson-Delmotte V., Jouzel J., Orsi A. Surface studies of water isotopes in Antarctica for quantitative interpretation of deep ice core data. Comptes Rendus Geoscience. 2017, 349: 139–150.

3. IMBIE team. Mass balance of the Antarctic ice sheet from 1992 to 2017. Nature. 2018, 558: 219–222.

4. Van den Broeke M. et al. Greenland ice sheet surface mass loss: recent developments in observation and modeling. Current Climate Change Reports. 2017, 3 (4): 345–356.

5. Ekaykin A.A., Lipenkov V.Ya., Barkov N.I., Petit J.R., Masson-Delmotte V. Spatial and temporal variability in isotope composition of recent snow in the vicinity of Vostok Station: Implications for ice-core interpretation. Annals of Glaciology. 2002, 35: 181–186.

6. Münch T., Kipfstuhl S., Freitag J., Meyer H., Laepple T. Regional climate signal vs. local noise: a two-dimensional view of water isotopes in Antarctic firn at Kohnen Station, Dronning Maud Land. Clim. Past. 2016, 12: 1565–1581.

7. Altnau S., Schlosser E., Isaksson E., Divine D. Climatic signals from 76 shallow firn cores in Dronning Maud Land, East Antarctica. The Cryosphere. 2015, 9: 925–944.

8. Casado M., Landais A., Picard G., Munch T., Laepple T., Stenni B., Dreossi G., Ekaykin A., Arnaud L., Genthon C., Touzeau A., Masson-Delmotte V., Jouzel J. Archival processes of the water stable isotope signal in East Antarctic ice cores. The Cryosphere. 2018, 12: 1745–1766.

9. Touzeau A., Landais A., Stenni B., Uemura R., Fukui K., Fujita S., Guilbaud S., Ekaykin A., Casado M., Barkan E., Luz B., Magand O., Teste G., LeMeur E., Baroni M., Savarino J., BourgeoisI., Risi C. Acquisition of isotopic composition for surface snow in East Antarctica and the links to climatic parameters. The Cryosphere. 2016, 10: 1–16.

10. Ekaykin A.A., Eberlein L., Lipenkov V.Ya., Popov S., Scheinert M., Schröder L., Turkeev A. Nonclimatic signal in ice core records: lessons from Antarctic megadunes. The Cryosphere. 2016, 10: 1217–1227.

11. Frezzotti M., Gandolfi S., Urbini S. Snow megadunes in Antarctica: Sedimentary structure and genesis. J. Geophys. Res. 2002, 107 (D18): 1–12.

12. Barkov N.I., Lipenkov V.Ya. Snow accumulation in the vicinity of Vostok Station in 1970 – 1973. Informaciony bulleten Sovetskoy Antarkticheskoy Ekspedicii. Information Bulletin of the Soviet Antarctic Expedition. 1978, 98: 63–68. [In Russian].

13. Popov S.V., Masolov V.N. Forty-seven new subglacial lakes in the 0–110° E sector of East Antarctica. J. Glaciol. 2007, 53 (181): 289–297.

14. Ekaykin A.A., Lipenkov V.Ya., Barkov N.I. Spatial and temporal structure of snow accumulation field in the vicinity of Vostok Station, Eastern Antarctic. Vestnik Sankt Peterburgskogo universiteta. Journal of St Petersburg State University, Series 7. 1998, 4 (28): 38–50. [In Russian].

15. Landais A., Ekaykin A.A., Barkan E., Winkler R., Luz B. Seasonal variations of 17O-excess and d-excess in snow precipitation at Vostok Station, East Antarctica. J. Glaciol. 2012, 58 (210): 725–733.

16. Tsyganova E.A., Popov S.V., Salamatin A.N., Lipenkov V.Ya. East Antarctica ice sheet flow along the Vostok flow line from the echosounding and modelling results. Led i sneg. Ice and Snow. 2010, 1 (109): 14–29. [In Russian].