Roles of atmospheric physics and model resolution in the simulation of two types of El Nino
Roles of atmospheric physics and model resolution in the simulation of two types of El Nino
复制标题
大气物理和模型分辨率在两类厄尔尼诺模拟中的作用
DOI：
10.1016/j.ocemod.2019.101468
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发表时间：
2019
期刊：
影响因子：
3.2
通讯作者：
Zhang Chan
中科院分区：
文献类型：
--
作者：
Yao Zhixiong;Tang Youmin;Lian Tao;Xu DongFeng;Li Xiaojing;Shen Zheqi;Zheng Jiayu;Zhang Banglin;Zhang Chan
在这项研究中，我们研究了大气模式分辨率和物理学对模拟两种类型的厄尔尼诺事件的可能影响。使用两种不同版本的社区大气模式(即CAM4和CAM5)，在两种不同分辨率下进行了四次实验。与CAM4试验相比，CAM5试验对两种类型的厄尔尼诺事件都有较长的周期，而分辨率较高的CAM5试验产生的周期与观测值最接近；CAM5试验在东太平洋厄尔尼诺事件期间温跃层深度的异常幅度也较大。4个耦合实验均能准确模拟中太平洋(CP)厄尔尼诺事件的位相锁定，但不能模拟EP厄尔尼诺事件的峰位相；具体地说，在两个CAM4实验中，峰位相出现得比观测值偏早。有趣的是，与分辨率较高或CAM4的实验相比，较低分辨率或CAM5的耦合实验可以产生更强的厄尔尼诺现象和更大的厄尔尼诺-南方涛动(ENSO)偏斜度。分辨率较高的CAM4实验的幅度最低，但与观测到的幅度最接近。对四个耦合实验的热量收支分析表明，耦合模式中的温跃层反馈比EP厄尔尼诺事件的温跃层反馈要大得多。模拟的纬向平流项存在较大的偏差，特别是在CP-El-Ni事件的发展阶段，通过平均Niño4区的平均流得到的异常温度梯度的纬向平流项是不切实际的负值，直接影响了耦合实验中对低分辨率的CP-El-Ni事件的模拟。
In this study, we examined the possible impacts of atmospheric model resolution and physics on simulating two types of El Niño events. Four experiments were conducted using two different versions of the Community Atmosphere Model (i.e., CAM4 and CAM5) at two different resolutions. Compared with the CAM4 experiments, the CAM5 experiments yielded longer periods for both types of El Niño events, while the period yielded by the CAM5 experiments with a higher resolution was closest to the observations; the CAM5 experiments also had a larger anomaly amplitude of the thermocline depth during Eastern-Pacific (EP) El Niño events. All four coupled experiments could accurately simulate the phase locking of the Central-Pacific (CP) El Niño events but not the peak phase of the EP El Niño events; specifically, in the two CAM4 experiments, the peak phase appeared too early compared with the observations. Interestingly, the coupled experiment with a lower resolution or CAM5 could yield much stronger El Niño and larger El Niño-Southern Oscillation (ENSO) skewness than the experiment with a higher resolution or CAM4. The amplitude in the CAM4 experiment with a higher resolution was the lowest but was closest to that observed. Heat budget analysis of each of the four coupled experiments demonstrated that the thermocline feedback in the coupled model was much larger than that observed for the EP El Niño events. There existed a large deviation in the simulated zonal advection terms; specifically, the zonal advection term of the anomalous temperature gradient found by averaging the mean current over the Niño4 region was unrealistically negative during the developing phase of the CP El Niño events and directly affected the simulation of the CP El Niño events in the coupled experiments with a lower resolution.