DOI: 10.5194/cp-14-789-2018
Scopus记录号: 2-s2.0-85048691342
论文题名: Climate sensitivity and meridional overturning circulation in the late Eocene using GFDL CM2.1
作者: Hutchinson D.K. ; De Boer A.M. ; Coxall H.K. ; Caballero R. ; Nilsson J. ; Baatsen M.
刊名: Climate of the Past
ISSN: 18149324
出版年: 2018
卷: 14, 期: 6 起始页码: 789
结束页码: 810
语种: 英语
Scopus关键词: climate modeling
; Eocene-Oligocene boundary
; ice sheet
; meridional circulation
; overturn
; paleoclimate
; paleogeography
; salinity
; sea surface temperature
; temperature gradient
; Antarctic Ice Sheet
; Antarctica
; Arctic
; Atlantic Ocean
; Atlantic Ocean (North)
; Pacific Ocean
; Pacific Ocean (North)
; Pacific Ocean (West)
; Southern Ocean
英文摘要: The Eocene-Oligocene transition (EOT), which took place approximately 34 Ma ago, is an interval of great interest in Earth's climate history, due to the inception of the Antarctic ice sheet and major global cooling. Climate simulations of the transition are needed to help interpret proxy data, test mechanistic hypotheses for the transition and determine the climate sensitivity at the time. However, model studies of the EOT thus far typically employ control states designed for a different time period, or ocean resolution on the order of 3°. Here we developed a new higher resolution palaeoclimate model configuration based on the GFDL CM2.1 climate model adapted to a late Eocene (38 Ma) palaeogeography reconstruction. The ocean and atmosphere horizontal resolutions are 1° × 1.5° and 3° × 3.75° respectively. This represents a significant step forward in resolving the ocean geography, gateways and circulation in a coupled climate model of this period. We run the model under three different levels of atmospheric CO2: 400, 800 and 1600 ppm. The model exhibits relatively high sensitivity to CO2 compared with other recent model studies, and thus can capture the expected Eocene high latitude warmth within observed estimates of atmospheric CO2. However, the model does not capture the low meridional temperature gradient seen in proxies. Equatorial sea surface temperatures are too high in the model (30-37 °C) compared with observations (max 32 °C), although observations are lacking in the warmest regions of the western Pacific. The model exhibits bipolar sinking in the North Pacific and Southern Ocean, which persists under all levels of CO2. North Atlantic surface salinities are too fresh to permit sinking (25-30 psu), due to surface transport from the very fresh Arctic (∼20 psu), where surface salinities approximately agree with Eocene proxy estimates. North Atlantic salinity increases by 1-2 psu when CO2 is halved, and similarly freshens when CO2 is doubled, due to changes in the hydrological cycle. © 2018 Author(s). Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109558
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: Department of Geological Sciences, Stockholm University, Stockholm, 10691, Sweden; Department of Meteorology, Stockholm University, Stockholm, 10691, Sweden; IMAU, Utrecht University, Princetonplein 5, Utrecht, 3584CC, Netherlands
Recommended Citation:
Hutchinson D.K.,De Boer A.M.,Coxall H.K.,et al. Climate sensitivity and meridional overturning circulation in the late Eocene using GFDL CM2.1[J]. Climate of the Past,2018-01-01,14(6)