| DOI: | 10.1175/JCLI-D-16-0735.1
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| Scopus记录号: | 2-s2.0-85025596055
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| 论文题名: | The role of natural climate variability in recent tropical expansion |
| 作者: | Allen R.J.; Kovilakam M.
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| 刊名: | Journal of Climate
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| ISSN: | 8948755
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| 出版年: | 2017
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| 卷: | 30, 期:16 | | 起始页码: | 6329
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| 结束页码: | 6350
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| 语种: | 英语
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| Scopus关键词: | Climatology
; Oceanography
; Tropics
; Atmospheric circulation
; Climate variability
; Community atmosphere model
; Eastern tropical pacific
; Multidecadal variability
; Natural climate variabilities
; Ocean-atmosphere models
; Sea surface temperature (SST)
; Climate models
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| 英文摘要: | Observations show the tropical belt has widened over the past few decades, a phenomenon associated with poleward migration of subtropical dry zones and large-scale atmospheric circulation. Coupled climate models also simulate tropical belt widening, but less so than observed. Reasons for this discrepancy, and the mechanisms driving the expansion remain uncertain. Here, the role of unforced, natural climate variability- particularly natural sea surface temperature (SST) variability-in recent tropical widening is shown. Compared to coupled ocean-atmosphere models, atmosphere-only simulations driven by observed SSTs consistently lead to larger rates of tropical widening, especially in the Northern Hemisphere (NH), highlighting the importance of recent SST evolution. Assuming the ensemble mean SSTs from historical simulations accurately represent the externally forced response, the observed SSTs can be decomposed into a forced and an unforced component. Targeted simulations with the Community Atmosphere Model, version 5 (CAM5), show that natural SST variability accounts for nearly all of the widening associated with recent SST evolution. This is consistent with the similarity of the unforced SSTs to the observed SSTs, both of which resemble a cold El Niño-Southern Oscillation/Pacific decadal oscillation (ENSO/PDO)-like SST pattern, which is associated with a wider tropical belt. Moreover, CAM5 coupled simulations with observed central to eastern tropical Pacific SSTs yield more than double the rate of widening compared to analogous simulations without prescribed tropical Pacific SSTs and reproduce the magnitude of tropical widening in atmosphere-only simulations. The results suggest that the bulk of recent tropical widening, particularly in the NH, is due to unforced, natural SST variability, primarily related to recent ENSO/PDO variability. © 2017 American Meteorological Society. |
| 资助项目: | NSF, National Science Foundation
; NASA, National Aeronautics and Space Administration
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| Citation statistics: |
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| 资源类型: | 期刊论文
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/48761
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| Appears in Collections: | 气候减缓与适应
气候变化与战略
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作者单位: | Oak Ridge National Laboratory, Oak Ridge, TN, United States
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| Recommended Citation: | |
Allen R.J.,Kovilakam M.. The role of natural climate variability in recent tropical expansion[J]. Journal of Climate,2017-01-01,30(16)
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