A continuous record of temperature evolution over a sequence of Dansgaard-Oeschger events during Marine Isotopic Stage 4 (76 to 62 kyr BP)
International audience [1] Our knowledge of the temperature evolution over Greenland during Dansgaard-Oeschger events (DO) is currently qualitatively described through the water isotopic profile. Using two independent paleothermometry methods, one based on air isotopic measurements and the other on...
Published in: | Geophysical Research Letters |
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Main Authors: | , , , , , , , , |
Other Authors: | , , , , , , , , , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
HAL CCSD
2004
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Subjects: | |
Online Access: | https://hal.science/hal-01103745 https://hal.science/hal-01103745/document https://hal.science/hal-01103745/file/41d25efe314386dd521dafadd804e71cf221.pdf https://doi.org/10.1029/2004GL021193 |
Summary: | International audience [1] Our knowledge of the temperature evolution over Greenland during Dansgaard-Oeschger events (DO) is currently qualitatively described through the water isotopic profile. Using two independent paleothermometry methods, one based on air isotopic measurements and the other on the combined measurements of water isotopes (dD and d 18 O), we show a complete and quantitative reconstruction of temperature at the NorthGRIP site over the period 76 to 62 kyr BP (DO 18, 19 and 20). We confirm that the associated warmings are larger than those conventionally depicted by the water isotopes (11°C, 16°C and 11°C for DO 18, 19 and 20). Secondly, we demonstrate that the relationship between temperature and d 18 O varies rapidly during the last glacial period, even over a DO. Finally, our temperature reconstruction over DO 19 agrees well with that predicted from simple climate models linking the DO to iceberg discharges. (2004), A continuous record of temperature evolution over a sequence of Dansgaard-Oeschger events during Marine Isotopic Stage 4 (76 to 62 kyr BP), Geophys. Res. Lett., 31, L22211, doi:10.1029/ 2004GL021193. [2] The last glacial cycle was characterized by millenial scale climate fluctuations that have been documented in the North Atlantic region through numerous marine and continental records [Bond et al., 1997; Genty et al., 2003]. The GRIP and GISP2 Summit ice cores [Dansgaard et al., 1993; Grootes et al., 1993] and the newly NorthGRIP [NorthGRIP Members, 2004] ice core exhibit 25 DO during the last glacial period. These events are characterized by rapid, e.g., in less than 100 years, and large, up to 16°C [Lang et al., 1999] warmings over Greenland. [3] Ice cores have already provided a wealth of information on DO in Greenland through the water isotopes for temperature changes, chemical records for atmospheric circulation and analysis of air bubbles for changes in greenhouse gases concentration. However, temperature reconstruction from water isotopes is subject to large biases mainly ... |
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