DOI: 10.1002/2015GL066042
论文题名: On the enigmatic similarity in Greenland δ18O between the Oldest and Younger Dryas
作者: Pausata F.S.R. ; Löfverström M.
刊名: Geophysical Research Letters
ISSN: 0094-8359
EISSN: 1944-8090
出版年: 2015
卷: 42, 期: 23 起始页码: 10470
结束页码: 10477
语种: 英语
英文关键词: deglaciation
; Greenland δ18O
; Heinrich events
; ice core temperature reconstructions
; moisture tracing
Scopus关键词: Carbon dioxide
; Climate change
; Climate models
; Glacial geology
; Ice
; Moisture
; Repair
; Atmospheric circulation model
; Deglaciations
; Greenland
; Heinrich Events
; Ice core
; Northern Hemispheres
; Temperature reconstruction
; Winter precipitation
; Atmospheric temperature
; deglaciation
; Heinrich event
; ice core
; moisture
; Older Dryas
; oxygen isotope
; paleoclimate
; Younger Dryas
; Arctic
; Greenland
英文摘要: The last deglaciation (20.0-10.0 kyr B.P.) was punctuated by two major cooling events affecting the Northern Hemisphere: the Oldest Dryas (OD; 18.0-14.7 kyr B.P.) and the Younger Dryas (YD; 12.8-11.5 kyr B.P.). Greenland ice core δ18O temperature reconstructions suggest that the YD was as cold as the OD, despite a 50 ppmv increase in atmospheric CO2, while modeling studies suggest that the YD was approximately 4-5°C warmer than the OD. This discrepancy has been surmised to result from changes in the origin of the water vapor delivered to Greenland; however, this hypothesis has not been hitherto tested. Here we use an atmospheric circulation model with an embedded moisture-tracing module to investigate atmospheric processes that may have been responsible for the similar δ18O values during the OD and YD. Our results show that the summer-to-winter precipitation ratio over central Greenland in the OD is twice as high as in the YD experiment, which shifts the δ18O signal toward warmer (summer) temperatures (enriched δ18O values and it accounts for ∼45% of the expected YD-OD δ18O difference). A change in the inversion (cloud) temperature relationship between the two climate states further contributes (∼20%) to altering the δ18O-temperature-relation model. Our experiments also show a 7% decrease of δ18O-depleted precipitation from distant regions (e.g., the Pacific Ocean) in the OD, hence further contributing (15-20%) in masking the actual temperature difference. All together, these changes provide a physical explanation for the ostensible similarity in the ice core δ18O temperature reconstructions in Greenland during OD and YD. © 2015. American Geophysical Union. All Rights Reserved. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84953639253&doi=10.1002%2f2015GL066042&partnerID=40&md5=11cde9c06b8c0c80a776bb832270acee
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/7975
Appears in Collections: 科学计划与规划 气候变化与战略
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作者单位: Department of Meteorology, Stockholm University, Bolin Centre for Climate Research, Stockholm, Sweden
Recommended Citation:
Pausata F.S.R.,Löfverström M.. On the enigmatic similarity in Greenland δ18O between the Oldest and Younger Dryas[J]. Geophysical Research Letters,2015-01-01,42(23).