TY - JOUR
T1 - New insights into the use of stable water isotopes at the northern Antarctic Peninsula as a tool for regional climate studies
AU - Fernandoy, Francisco
AU - Tetzner, Dieter
AU - Meyer, Hanno
AU - Gacitúa, Guisella
AU - Hoffmann, Kirstin
AU - Falk, Ulrike
AU - Lambert, Fabrice
AU - MacDonell, Shelley
N1 - Funding Information:
Acknowledgements. The present work was funded by the FONDE-CYT project 11121551 and supported by the Chilean Antarctic Institute (INACH), the Chilean Air Force and Army logistical facilities. We want to show our gratitude to the Universidad Nacional Andres Bello for supporting this study. We also greatly thank our colleagues, who made field work conditions less severe, especially to Daniel Rutllant for his support in the logistical and field safety. We would like to thank all people involved in the laboratory work, especially to Ivonne Quintanilla, who carried out the sample processing at UNAB and to Johannes Freitag, for his support with the X-Ray tomography processing at AWI. Tracy Wormwood is greatly thanked for her support editing this manuscript. We highly appreciate the comments of two anonymous reviewers, who provided helpful observations that greatly contributed to improve this manuscript. Finally, we thank the dedicated work of the editor of this article Benjamin Smith.
PY - 2018/3/26
Y1 - 2018/3/26
N2 - Due to recent atmospheric and oceanic warming, the Antarctic Peninsula is one of the most challenging regions of Antarctica to understand in terms of both local-and regional-scale climate signals. Steep topography and a lack of long-term and in situ meteorological observations complicate the extrapolation of existing climate models to the sub-regional scale. Therefore, new techniques must be developed to better understand processes operating in the region. Isotope signals are traditionally related mainly to atmospheric conditions, but a detailed analysis of individual components can give new insight into oceanic and atmospheric processes. This paper aims to use new isotopic records collected from snow and firn cores in conjunction with existing meteorological and oceanic datasets to determine changes at the climatic scale in the northern extent of the Antarctic Peninsula. In particular, a discernible effect of sea ice cover on local temperatures and the expression of climatic modes, especially the Southern Annular Mode (SAM), is demonstrated. In years with a large sea ice extension in winter (negative SAM anomaly), an inversion layer in the lower troposphere develops at the coastal zone. Therefore, an isotope-temperature relationship (δ-T) valid for all periods cannot be obtained, and instead the δ-T depends on the seasonal variability of oceanic conditions. Comparatively, transitional seasons (autumn and spring) have a consistent isotope-temperature gradient of +0.69 °C-1. As shown by firn core analysis, the near-surface temperature in the northern-most portion of the Antarctic Peninsula shows a decreasing trend (-0.33°Cyear-1) between 2008 and 2014. In addition, the deuterium excess (dexcess) is demonstrated to be a reliable indicator of seasonal oceanic conditions, and therefore suitable to improve a firn age model based on seasonal dexcess variability. The annual accumulation rate in this region is highly variable, ranging between 1060 and 2470kgm-2year-1 from 2008 to 2014. The combination of isotopic and meteorological data in areas where data exist is key to reconstruct climatic conditions with a high temporal resolution in polar regions where no direct observations exist.
AB - Due to recent atmospheric and oceanic warming, the Antarctic Peninsula is one of the most challenging regions of Antarctica to understand in terms of both local-and regional-scale climate signals. Steep topography and a lack of long-term and in situ meteorological observations complicate the extrapolation of existing climate models to the sub-regional scale. Therefore, new techniques must be developed to better understand processes operating in the region. Isotope signals are traditionally related mainly to atmospheric conditions, but a detailed analysis of individual components can give new insight into oceanic and atmospheric processes. This paper aims to use new isotopic records collected from snow and firn cores in conjunction with existing meteorological and oceanic datasets to determine changes at the climatic scale in the northern extent of the Antarctic Peninsula. In particular, a discernible effect of sea ice cover on local temperatures and the expression of climatic modes, especially the Southern Annular Mode (SAM), is demonstrated. In years with a large sea ice extension in winter (negative SAM anomaly), an inversion layer in the lower troposphere develops at the coastal zone. Therefore, an isotope-temperature relationship (δ-T) valid for all periods cannot be obtained, and instead the δ-T depends on the seasonal variability of oceanic conditions. Comparatively, transitional seasons (autumn and spring) have a consistent isotope-temperature gradient of +0.69 °C-1. As shown by firn core analysis, the near-surface temperature in the northern-most portion of the Antarctic Peninsula shows a decreasing trend (-0.33°Cyear-1) between 2008 and 2014. In addition, the deuterium excess (dexcess) is demonstrated to be a reliable indicator of seasonal oceanic conditions, and therefore suitable to improve a firn age model based on seasonal dexcess variability. The annual accumulation rate in this region is highly variable, ranging between 1060 and 2470kgm-2year-1 from 2008 to 2014. The combination of isotopic and meteorological data in areas where data exist is key to reconstruct climatic conditions with a high temporal resolution in polar regions where no direct observations exist.
UR - http://www.scopus.com/inward/record.url?scp=85044422420&partnerID=8YFLogxK
U2 - 10.5194/tc-12-1069-2018
DO - 10.5194/tc-12-1069-2018
M3 - Article
AN - SCOPUS:85044422420
SN - 1994-0416
VL - 12
SP - 1069
EP - 1090
JO - Cryosphere
JF - Cryosphere
IS - 3
ER -
