DOI: 10.5194/cp-10-137-2014
Scopus记录号: 2-s2.0-84892700243
论文题名: Limited response of peatland CH4 emissions to abrupt Atlantic Ocean circulation changes in glacial climates
作者: Hopcroft P.O. ; Valdes P.J. ; Wania R. ; Beerling D.J.
刊名: Climate of the Past
ISSN: 18149324
出版年: 2014
卷: 10, 期: 1 起始页码: 137
结束页码: 154
语种: 英语
Scopus关键词: carbon cycle
; concentration (composition)
; Dansgaard-Oeschger cycle
; ecosystem modeling
; hydrological cycle
; ice core
; Last Glacial
; methane
; oceanic circulation
; paleoclimate
; peatland
; permafrost
; thermodynamics
; warming
; wetland
; Arctic
; Atlantic Ocean
; Europe
; Greenland
英文摘要: Ice-core records show that abrupt Dansgaard-Oeschger (D-O) climatic warming events of the last glacial period were accompanied by large increases in the atmospheric CH4 concentration (up to 200 ppbv). These abrupt changes are generally regarded as arising from the effects of changes in the Atlantic Ocean meridional overturning circulation and the resultant climatic impact on natural CH4 sources, in particular wetlands. We use two different ecosystem models of wetland CH4 emissions to simulate northern CH4 sources forced with coupled general circulation model simulations of five different time periods during the last glacial to investigate the potential influence of abrupt ocean circulation changes on atmospheric CH 4 levels during D-O events. The simulated warming over Greenland of 7-9 °C in the different time periods is at the lower end of the range of 11-15 °C derived from ice cores, but is associated with strong impacts on the hydrological cycle, especially over the North Atlantic and Europe during winter. We find that although the sensitivity of CH4 emissions to the imposed climate varies significantly between the two ecosystem emissions models, the model simulations do not reproduce sufficient emission changes to satisfy ice-core observations of CH4 increases during abrupt events. The inclusion of permafrost physics and peatland carbon cycling in one model (LPJ-WHyMe) increases the climatic sensitivity of CH44 emissions relative to the Sheffield Dynamic Global Vegetation Model (SDGVM) model, which does not incorporate these processes. For equilibrium conditions this additional sensitivity is mostly due to differences in carbon cycle processes, whilst the increased sensitivity to the imposed abrupt warmings is also partly due to the effects of freezing on soil thermodynamics. These results suggest that alternative scenarios of climatic change could be required to explain the abrupt glacial CH4 variations, perhaps with a more dominant role for tropical wetland CH4 sources.©Author(s) 2014. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/49322
Appears in Collections: 气候变化与战略
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Recommended Citation:
Hopcroft P.O.,Valdes P.J.,Wania R.,et al. Limited response of peatland CH4 emissions to abrupt Atlantic Ocean circulation changes in glacial climates[J]. Climate of the Past,2014-01-01,10(1)