DOI: 10.1175/JCLI-D-17-0154.1
Scopus记录号: 2-s2.0-85040635718
论文题名: A robust null hypothesis for the potential causes of megadrought in Western North America
作者: Ault T.R. ; George S.S. ; Smerdon J.E. ; Coats S. ; Mankin J.S. ; Carrillo C.M. ; Cook B.I. ; Stevensong S.
刊名: Journal of Climate
ISSN: 8948755
出版年: 2018
卷: 31, 期: 1 起始页码: 3
结束页码: 24
语种: 英语
英文关键词: Decadal variability
; Drought
; ENSO
; North America
; Tree rings
Scopus关键词: Climatology
; Drought
; Oceanography
; Statistical tests
; Surface waters
; Decadal variability
; ENSO
; Internal climate variability
; North America
; Paleoclimate reconstruction
; Sea surface temperature anomalies
; Self-calibrated palmer drought severity indices
; Tree rings
; Climate change
; boundary condition
; climate variation
; decadal variation
; drought
; El Nino-Southern Oscillation
; hypothesis testing
; tree ring
; United States
英文摘要: The western United States was affected by several megadroughts during the last 1200 years, most prominently during the Medieval Climate Anomaly (MCA; 800 to 1300 CE). A null hypothesis is developed to test the possibility that, given a sufficiently long period of time, these events are inevitable and occur purely as a consequence of internal climate variability. The null distribution of this hypothesis is populated by a linear inverse model (LIM) constructed from global sea surface temperature anomalies and self-calibrated Palmer drought severity index data for North America. Despite being trained only on seasonal data from the late twentieth century, the LIM produces megadroughts that are comparable in their duration, spatial scale, and magnitude to the most severe events of the last 12 centuries. The null hypothesis therefore cannot be rejected with much confidence when considering these features of megadrought, meaning that similar events are possible today, even without any changes to boundary conditions. In contrast, the observed clustering of megadroughts in the MCA, as well as the change in mean hydroclimate between the MCA and the 1500-2000 period, are more likely to have been caused by either external forcing or by internal climate variability not well sampled during the latter half of the twentieth century. Finally, the results demonstrate that the LIM is a viable tool for determining whether paleoclimate reconstructions events should be ascribed to external forcings or to "out of sample" climate mechanisms, or if they are consistent with the variability observed during the recent period. © 2018 American Meteorological Society. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/111722
Appears in Collections: 气候减缓与适应
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作者单位: Department of Earth and Atmospheric Science, Cornell University, Ithaca, NY, United States; Department of Geography, University of Minnesota, Twin Cities, Minneapolis, MN, United States; Division of Ocean and Climate Physics, Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, United States; Climate and Large Scale Dynamics Laboratory, National Center for Atmospheric Research, Boulder, CO, United States; NASA Goddard Institute for Space Studies, New York, NY, United States; Department of Geography, Dartmouth College, Hanover, NH, United States; Bren School of Environmental Science and Management, University of California, Santa Barbara, Santa Barbara, CA, United States
Recommended Citation:
Ault T.R.,George S.S.,Smerdon J.E.,et al. A robust null hypothesis for the potential causes of megadrought in Western North America[J]. Journal of Climate,2018-01-01,31(1)