气候变化领域集成服务门户(CCPortal): Last glacial inception trajectories for the Northern Hemisphere from coupled ice and climate modelling

CCPortal

DOI	10.5194/cp-17-397-2021
	Last glacial inception trajectories for the Northern Hemisphere from coupled ice and climate modelling
	Bahadory T.; Tarasov L.; Andres H.
发表日期	2021
ISSN	1814-9324
起始页码	341
结束页码	369
卷号	17 期号:1
英文摘要	We present an ensemble of last glacial inception (LGI) simulations for the Northern Hemisphere that captures a significant fraction of inferred ice volume changes within proxy uncertainties. This ensemble was performed with LCice 1.0, a coupled ice sheet and climate model, varying parameters of both climate and ice sheet components, as well as the coupling between them. Certain characteristics of the spatiotemporal pattern of ice growth and subsequent retreat in both North America (NA) and Eurasia (EA) are sensitive to parameter changes while others are not. We find that the initial inception of ice over NA and EA is best characterized by the nucleation of ice at high-latitude and high-elevation sites. Subsequent spreading and merger along with large-scale conversion of snowfields dominate in different sectors. The latter plays an important role in the merging of eastern and western ice regions in NA. The inception peak ice volume in the ensemble occurs approximately at 111 ka and therefore lags the summer 60 N insolation minimum by more than 3 kyr. Ice volumes consistently peak earlier over EA than NA. The inception peak in North America is characterized by a merged Laurentide and Cordilleran ice sheet, with the Davis Strait covered in ice in ~ 80% of simulations. Ice also bridges Greenland and Iceland in all runs by 114 ka and therefore blocks the Denmark Strait. This latter feature would thereby divert the East Greenland Current and Denmark Strait overflow with a potentially significant impact on ocean circulation. The Eurasian ice sheet at its inception peak varies across ensemble runs between a continuous ice sheet and multiple smaller ice caps. In both continents, the colder high latitudes (i.e. Ellesmere and Svalbard) tend to grow ice through the entire simulation (to 102 ka), while lower latitudes lose ice after ~ 110 ka. We find temperature decreases over the initial phases of the inception lead to the expansion of NA ice sheet area and that subsequent precipitation increases contribute to its thickening. EA ice sheet area also expands with decreasing temperatures, but sea ice limits any increases in precipitation, leading to an earlier retreat away from the EA maximum ice sheet volume. We also examine the extent to which the capture of both LGI ice growth and retreat constrains the coupled ice- climate model sensitivity to changing atmospheric pCO2. The 55-member sub-ensemble that meets our criteria for "acceptable" ice growth and retreat has an equilibrium climate sensitivity lower bound that is 0.3 °C higher than that of the full ensemble. This suggests some potential value of fully coupled ice-climate modelling of the last glacial inception to constrain future climate change. © 2021 Copernicus GmbH. All rights reserved.
来源期刊	Climate of the Past
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/183605
作者单位	Memorial University of Newfoundland and Labrador, St. John's, NL A1C 5S7, Canada
推荐引用方式 GB/T 7714	Bahadory T.,Tarasov L.,Andres H.. Last glacial inception trajectories for the Northern Hemisphere from coupled ice and climate modelling[J],2021,17(1).
APA	Bahadory T.,Tarasov L.,&Andres H..(2021).Last glacial inception trajectories for the Northern Hemisphere from coupled ice and climate modelling.Climate of the Past,17(1).
MLA	Bahadory T.,et al."Last glacial inception trajectories for the Northern Hemisphere from coupled ice and climate modelling".Climate of the Past 17.1(2021).