DOI: 10.1175/JCLI-D-12-00820.1
Scopus记录号: 2-s2.0-84888048390
论文题名: Dehumidification over tropical continents reduces climate sensitivity and inhibits snowball earth initiation
作者: Fiorella R.P. ; Poulsen C.J.
刊名: Journal of Climate
ISSN: 8948755
出版年: 2013
卷: 26, 期: 23 起始页码: 9677
结束页码: 9695
语种: 英语
Scopus关键词: Climate sensitivity
; Glaciation
; Paleoclimates
; Radiative fluxes
; Walker circulation
; Carbon dioxide
; Earth (planet)
; Glacial geology
; Humidity control
; Solar radiation
; Topography
; Tropics
; Troposphere
; Water vapor
; Weathering
; Climate models
; albedo
; atmospheric moisture
; carbon dioxide
; chemical weathering
; concentration (composition)
; evaporation
; geological record
; irradiance
; marine atmosphere
; paleoclimate
; Proterozoic
; solar radiation
; tropical meteorology
; troposphere
; Walker circulation
; water vapor
英文摘要: The enigmatic Neoproterozoic geological record suggests the potential for a fully glaciated "snowball Earth." Low-latitude continental position has been invoked as a potential snowball Earth trigger by increasing surface albedo and decreasing atmospheric CO2 concentrations through increased silicate weathering. Herein, climate response to the reduction of total solar irradiance (TSI) and CO2 concentration is tested using four different land configurations (aquaplanet, modern, Neoproterozoic, and low-latitude supercontinent) with uniform topography in the NCAR Community Atmosphere Model, version 3.1 (CAM3.1), GCM with a mixed layer ocean. Despite a lower surface albedo at 100% TSI, the threshold for global glaciation decreases from 92% TSI in the aquaplanet configuration to 85% TSI with a low-latitude supercontinent. The difference in thresholds is principally because of the partitioning of local longwave cooling relative to poleward energy transport. Additionally, dehumidification of the troposphere over large tropical continents in CAM3.1 increases direct heating by decreasing cloud cover. Continental heating intensifies the Walker circulation, enhancing surface evaporation and moistening the marine troposphere. Topography also provides an important control on snowball Earth initiation. Modern topography in the modern continental arrangement eases snowball initiation, requiring a 2% smaller reduction in TSI relative to a modern continental arrangement without topography. In the absence of potential silicate weathering feedbacks, large tropical landmasses raise the barrier to initiation of snowball events. More generally, these simulations demonstrate the substantial influence of geography on climate sensitivity and challenge the notion that the reduced continental area early in Earth history might provide a solution to the faint young Sun paradox. © 2013 American Meteorological Society. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/51526
Appears in Collections: 气候变化事实与影响
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作者单位: Department of Earth and Environmental Sciences, University of Michigan, 2534 CC Little Building, 1100 N. University Avenue, Ann Arbor, MI 48109-1005, United States
Recommended Citation:
Fiorella R.P.,Poulsen C.J.. Dehumidification over tropical continents reduces climate sensitivity and inhibits snowball earth initiation[J]. Journal of Climate,2013-01-01,26(23)