DOI: 10.1175/JCLI-D-16-0509.1
Scopus记录号: 2-s2.0-85017122313
论文题名: Assessing the impact of model biases on the projected increase in frequency of extreme positive Indian Ocean dipole events
作者: Wang G. ; Cai W. ; Santoso A.
刊名: Journal of Climate
ISSN: 8948755
出版年: 2017
卷: 30, 期: 8 起始页码: 2757
结束页码: 2767
语种: 英语
Scopus关键词: Atmospheric temperature
; Oceanography
; Rain
; Stream flow
; Surface waters
; Climate projection
; Eastern equatorial Indian ocean
; High frequency HF
; Impact on surfaces
; Indian Ocean dipole
; Indian ocean dipoles
; Sea Surface Temperature gradients
; Tropical variability
; Climate models
英文摘要: For many generations, models simulate an Indian Ocean dipole (IOD) that is overly large in amplitude. The possible impact of this systematic bias on climate projections, including a projected frequency increase in extreme positive IOD (pIOD) using a rainfall-based definition, has attracted attention. In particular, a recent study suggests that the increased frequency is an artifact of the overly large IOD amplitude. In contrast, here the opposite is found. Through intermodel ensemble regressions, the present study shows that models producing a high frequency in the present-day climate generate a small future frequency increase. The frequency is associated with the mean equatorial west-minus-east sea surface temperature (SST) gradient: the greater the gradient, the greater the frequency because it is easier to shift convection to the west, which characterizes an extreme pIOD. A greater present-day gradient is associated with a present-day shallower thermocline, lower SSTs, and lower rainfall in the eastern equatorial Indian Ocean (EEIO). Because there is an inherent limit for a maximum rainfall reduction and for the impact on surface cooling by a shallowing of an already shallow mean EEIO thermocline, there is a smaller increase in frequency in models with a shallower present-day EEIO thermocline. Given that a bias of overly shallow EEIO thermocline and overly low EEIO SSTs and rainfall is common in models, the future frequency increase should be underestimated, opposite to an implied overestimation resulting from the overly large IOD amplitude bias. Therefore, correcting the projected frequency from a single bias, without considering other biases that are present, is not appropriate and should be avoided. © 2017 American Meteorological Society.
资助项目: ARC, Australian Research Council
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/49708
Appears in Collections: 气候变化事实与影响
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作者单位: CSIRO Oceans and Atmosphere Flagship, Aspendale, VIC, Australia; Physical Oceanography Laboratory, Qingdao Collaborative Innovation Centre of Marine Science and Technology, Ocean University of China, Qingdao, China; ARC Centre of Excellence for Climate System Science, University of New South Wales, Sydney, NSW, Australia; Climate Change Research Centre, University of New South Wales, Sydney, NSW, Australia
Recommended Citation:
Wang G.,Cai W.,Santoso A.. Assessing the impact of model biases on the projected increase in frequency of extreme positive Indian Ocean dipole events[J]. Journal of Climate,2017-01-01,30(8)