CMIP5模式对拉尼娜生命史模拟能力的评估  

Evaluation of simulation capability of CMIP5 multi-models for La Nia events

作　　者：黄玉蓉[1] 张福颖[2] 陈明诚[2] HUANG Yurong ZHANG Fuying CHEN Mingcheng(College of Marine Sciences, Shanghai Ocean University, Shanghai 210306, China Nanjing University of Information Science ＆ Technology, Nanjing 210044, China)

机构地区：[1]上海海洋大学海洋科学学院,上海201306 [2]南京信息工程大学,江苏南京210044

出　　处：《大气科学学报》2017年第3期356-368,共13页Transactions of Atmospheric Sciences

基　　金：江苏省自然科学基金重点项目(BK20150062)

摘　　要：利用19个CMIP5模式输出资料,评估模式对于拉尼娜事件特殊生命史发展过程的模拟能力。评估结果显示,仅有少数模式可以很好地再现拉尼娜事件缓慢衰减并再次增强的生命史发展过程,而多数模式中拉尼娜事件持续衰减直至消亡。观测分析结果表明,一个可能导致拉尼娜再次增强的原因是风场强迫作用下的海洋赤道波动过程。模拟能力较好的模式可以建立起"SST—对流—风场"正反馈过程,使得拉尼娜事件再次发展。而模拟能力较弱的模式中正反馈过程无法建立,因此拉尼娜事件最终消亡。另一个可能导致拉尼娜事件再次增强的原因是海洋平均经圈环流的作用。模拟能力较好的模式可以很好地模拟出气候态海洋经圈环流强度,因此海洋平均经向冷平流会帮助赤道地区负海温距平再次增强。而模拟能力较弱的模式中海洋经圈环流强度较弱,因此赤道地区负海温距平持续衰减,最终回归到气候态。Observed sea surface temperature anomaly（SSTA） in the equatorial eastern Pacific exhibits an interesting evolution characteristic in La Ni（n）a life cycle,which is characterized by a weaker decay after its peak and a re-intensification of cold SSTA in the second year.Based on the output data in 19 CMIP5 models,the special evolution features of La Nifa events are investigated.The simulation capability of CMIP5 multi-models for La Ni（n）a life cycle is evaluated.Evaluation results show that only a few good models can capture the slow decaying and re-intensification processes in La Ni（n）a life cycle,while La Ni（n）a continues decaying to the neutral state in the rest of pool models.The physical mechanisms that caused the distinctive evolution features are carried out by an oceanic subsurface heat budget analysis.The result shows that the major differences between good models and pool models lie in wind,which induces anomalous zonal advection and mean meridional advection associated with subtropical cell.The first possible mechanism that caused the re-intensification process of La Ni（n）a is the wind-forced equatorial wave dynamics.As both the mean upwelling and the mean zonal temperature gradient along the equator reach a maximum in boreal fall,northern autumn is the season of the strongest coupled ENSO instability when the cold tongue is the strongest.With re-intensification of easterly wind anomalies in northern fall,the thermocline shoals again continue towards the end of the year.Thus,it is found that a positive feedback of SST-convection-wind,which makes La Ni（n）a re-develop,can be established in the good models,while such a positive feedback does not exist in the poor models.The other possible mechanism is the meridional mean ocean advection process related to the ocean mean subtropical cell.The good models can simulate the intensity of climatological mean subtropical cell well,thus the off-equatorial anomalous cold subsurface water is likely to be advected equatorward by the mean curre

关 键 词：海气间相互作用 模式评估 ENSO动力学 生命史不对称性 热量收支诊断分析 

分 类 号：P732[天文地球—海洋科学]