Tropical Ocean Contributions to California’s Surprisingly Dry El Ni?o of 2015/16
Tropical Ocean Contributions to California’s Surprisingly Dry El Ni?o of 2015/16
复制标题
热带海洋对 2015/2016 年加利福尼亚州异常干燥的厄尔尼诺现象的影响
DOI：
10.1175/jcli-d-17-0177.1
复制
发表时间：
2017
影响因子：
4.9
通讯作者：
Li Xichen
中科院分区：
文献类型：
--
作者：
Siler Nicholas;Kosaka Yu;Xie Shang-Ping;Li Xichen
2015/16年的主要厄尔尼诺现象给加州带来的降雨量比之前同等强度的事件要少得多，这让该州连续第四年遭受严重干旱的居民非常失望。这里，加州2015/16年相对于之前主要厄尔尼诺事件的弱降水是在一个40人的纯大气模拟集合中进行的，该集合运行了历史的海洋表面温度(SST)和持续的辐射强迫。模拟显示，2015/16年度加州降水和大尺度大气环流与之前的强厄尔尼诺事件存在显著差异，这与观测中发现的差异相似(尽管弱于)。主成分分析表明，这些集合-平均差异可能与热带海温变率模式有关，印度洋和西太平洋信号较强，赤道东太平洋和副热带北大西洋信号较弱。大多数预测模型都忽略了这种SST模式，这可能在一定程度上解释了他们对2015/16年度加州降雨量高于平均水平的错误预测。
The major El Niño of 2015/16 brought significantly less precipitation to California than previous events of comparable strength, much to the disappointment of residents suffering through the state’s fourth consecutive year of severe drought. Here, California’s weak precipitation in 2015/16 relative to previous major El Niño events is investigated within a 40-member ensemble of atmosphere-only simulations run with historical sea surface temperatures (SSTs) and constant radiative forcing. The simulations reveal significant differences in both California precipitation and the large-scale atmospheric circulation between 2015/16 and previous strong El Niño events, which are similar to (albeit weaker than) the differences found in observations. Principal component analysis indicates that these ensemble-mean differences were likely related to a pattern of tropical SST variability with a strong signal in the Indian Ocean and western Pacific and a weaker signal in the eastern equatorial Pacific and subtropical North Atlantic. This SST pattern was missed by the majority of forecast models, which could partly explain their erroneous predictions of above-average precipitation in California in 2015/16.