DOI: 10.1007/s00382-017-3713-y
Scopus记录号: 2-s2.0-85018997277
论文题名: Association between mean and interannual equatorial Indian Ocean subsurface temperature bias in a coupled model
作者: Srinivas G. ; Chowdary J.S. ; Gnanaseelan C. ; Prasad K.V.S.R. ; Karmakar A. ; Parekh A.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2018
卷: 50, 期: 2018-05-06 起始页码: 1659
结束页码: 1673
语种: 英语
英文关键词: Coupled model
; Indian Ocean
; La Niña
; SST
; Subsurface temperature
Scopus关键词: air-sea interaction
; annual variation
; atmosphere-ocean coupling
; climate modeling
; convergence
; current direction
; downwelling
; La Nina
; oceanic general circulation model
; sea surface temperature
; summer
; warming
; westerly
; Indian Ocean
; Indian Ocean (Equatorial)
英文摘要: In the present study the association between mean and interannual subsurface temperature bias over the equatorial Indian Ocean (EIO) is investigated during boreal summer (June through September; JJAS) in the National Centers for Environmental Prediction (NCEP) Climate Forecast System (CFSv2) hindcast. Anomalously high subsurface warm bias (greater than 3 °C) over the eastern EIO (EEIO) region is noted in CFSv2 during summer, which is higher compared to other parts of the tropical Indian Ocean. Prominent eastward current bias in the upper 100 m over the EIO region induced by anomalous westerly winds is primarily responsible for subsurface temperature bias. The eastward currents transport warm water to the EEIO and is pushed down to subsurface due to downwelling. Thus biases in both horizontal and vertical currents over the EIO region support subsurface warm bias. The evolution of systematic subsurface warm bias in the model shows strong interannual variability. These maximum subsurface warming episodes over the EEIO are mainly associated with La Niña like forcing. Strong convergence of low level winds over the EEIO and Maritime continent enhanced the westerly wind bias over the EIO during maximum warming years. This low level convergence of wind is induced by the bias in the gradient in the mean sea level pressure with positive bias over western EIO and negative bias over EEIO and parts of western Pacific. Consequently, changes in the atmospheric circulation associated with La Niña like conditions affected the ocean dynamics by modulating the current bias thereby enhancing the subsurface warm bias over the EEIO. It is identified that EEIO subsurface warming is stronger when La Niña co-occurred with negative Indian Ocean Dipole events as compared to La Niña only years in the model. Ocean general circulation model (OGCM) experiments forced with CFSv2 winds clearly support our hypothesis that ocean dynamics influenced by westerly winds bias is primarily responsible for the strong subsurface warm bias over the EEIO. This study advocates the importance of understanding the ability of the models in representing the large scale air–sea interactions over the tropics and their impact on ocean biases for better monsoon forecast. © 2017, Springer-Verlag Berlin Heidelberg. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109433
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
There are no files associated with this item.
作者单位: Indian Institute of Tropical Meteorology (IITM), Pune, 411 008, India; Department of Meteorology and Oceanography, Andhra University, Visakhapatnam, 530 003, India; Department of Atmospheric and Space Sciences, Savitribai Phule Pune University, Pune, 411 007, India
Recommended Citation:
Srinivas G.,Chowdary J.S.,Gnanaseelan C.,et al. Association between mean and interannual equatorial Indian Ocean subsurface temperature bias in a coupled model[J]. Climate Dynamics,2018-01-01,50(2018-05-06)