| Title | Tropical Pacific-high latitude South Atlantic teleconnections as seen in O18/O16 variability in Antarctic coastal ice cores |
| Author | Divine, D.V.; Isaksson, E.; Kaczmarska, M.; Godtliebsen, F.; Oerter, H.; Schlosser, E.; Johnsen, S.J.; van den Broeke, M.; van de Wal, R.S.W. |
| Author Affil | Divine, D.V., Norwegian Polar Institute, Tromso, Norway. Other: University of Tromso, Norway; Alfred Wegener Institute for Polar and Marine Research, Federal Republic of Germany; University of Innsbruck, Austria; University of Copenhagen, Denmark; Utrecht University, Netherlands |
| Source | Journal of Geophysical Research, 114(D11), Citation D11112. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0148- 0227 |
| Publication Date | 2009 |
| Notes | In English. 58 refs. GeoRef Acc. No: 300763. CRREL Acc. No: 64005229 |
| Index Terms | climatic change; ice; isotopes; oxygen; temperature; Pacific Ocean; Antarctica--Queen Maud Land; Antarctica; climate change; decadal variations; El Nino Southern Oscillation; ice cores; isotope ratios; O-18/O-16; ocean circulation; Queen Maud Land; sea ice; sea-surface temperature; Southern Annular Mode; stable isotopes; teleconnections; tropical environment |
| Abstract | We use a network of eight ice cores from coastal Dronning Maud Land (DML), Antarctica, to examine the role of the tropical ENSO (El Nino-Southern Oscillation) in the temporal variability of delta 18O in annual accumulation. The longest record from the S100 ice core covering the period 1737- 1999 is used to analyze the teleconnections between the tropical Pacific and coastal DML on decadal scales and longer. A shorter stacked coastal DML delta 18O series spanning 1955-1999 is constructed to assess the variability of ENSO teleconnection on interannual scales. Results suggest that, on typical ENSO timescales of 2-6 years, the strength of the teleconnection varies in time, being stronger for years with generally negative phase of the Southern Annular Mode (SAM). On the timescales of approximately two decades (bidecadal), positive isotope anomalies are associated with oceanic warming and a westward sea surface temperature (SST) gradient in the equatorial Pacific. Bidecadal variability in SAM, forced by the tropical Pacific, is proposed as a critical element in the teleconnection. Our analysis suggests that a multidecadal positive trend in the annual mean delta 18O values from the analyzed cores can be indicative of the atmospheric warming that begun in this part of the DML already in the 1910s. The trend in delta 18O, quantified in terms of long-term surface air temperature (SAT) changes, is consistent with the instrumental data. Yet, we speculate that the accurate estimation of SAT trends requires an assessment of the potential role of secular SAM and sea ice extent changes in shaping the isotopic signal. |
| URL | http://hdl.handle.net/10.1029/2008JD010475 |
| Publication Type | journal article |
| Record ID | 88774 |