Spring Cold Bias of SST and Minimal Wind Mixing in the Equatorial Pacific Cold Tongue

• Published in: Atmospheric and oceanic science letters = Daqi-he-haiyang-kexue-kuaibao Vol. 3; no. 6; pp. 342 - 346
• Main Author: LIN Peng-Fei LIU Hai-Long LI Chao ZHANG Xue-Hong
• Format: Journal Article
• Language: English
• Published: Routledge 2010; State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
• Subjects: cold biases; the equatorial Pacific cold tongue; the minimal wind mixing; 大洋环流模式; 混合表面; 赤道东太平洋; 赤道太平洋; cold biases; the minimal wind mixing; the equatorial Pacific cold tongue
• ISSN: 1674-2834; 2376-6123
• DOI: 10.1080/16742834.2010.11446890

The authors investigate the relationship between bias in simulated sea surface temperature （SST） in the equatorial eastern Pacific cold tongue during the boreal spring as simulated by an oceanic general circulation model （OGCM） and minimal wind mixing （MWM） at the surface. The cold bias of simulated SST is the greatest during the boreal spring, at approximately 3℃. A sensi- tivity experiment reducing MWM by one order of magnitude greatly alleviates cold biases, especially in March-April. The decrease in bias is primarily due to weakened vertical mixing, which preserves heat in the uppermost layer and results in warmer simulated SST. The reduction in vertical mixing also leads to a weak westward current in the upper layer, which further contributes to SST warming. These findings imply that there are large uncertainties about simple model parameters such as MWM at the oceanic surface.