Modeling and Observational Study of Decadal El Nino-Southern Oscillation (ENSO) Modulation and Tropical Pacific Decadal Variability

十年厄尔尼诺-南方涛动（ENSO）调制和热带太平洋年代际变化的模拟和观测研究

• 批准号: 1302346
• 负责人: Yuko Okumura
• 金额: $ 48.24万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-05-01 至 2017-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1302346&HistoricalAwards=false
• 关键词: Modeling; Observational; Study; Decadal; El

The El Nino-Southern Oscillation (ENSO) phenomenon provides an important source of climate predictability on interannual time scales. The research aims for mechanistic understanding of the processes important to the decadal modulation of ENSO and tropical Pacific decadal variability through model experiments and observational analysis. It is hypothesized that the low frequency components of stochastic atmospheric variability in the North and South Pacific, namely, the North Pacific Oscillation (NPO) and Pacific-South American (PSA) variability, independently drive tropical Pacific decadal variability. Furthermore the tropical Pacific decadal variability driven by NPO interacts with ENSO and modulates its amplitude through meridional displacement of the mean intertropical convergence zone (ITCZ). The PSA variability, on the other hand, appears to drive ENSO-like decadal variability associated with the Pacific Decadal Oscillation (PDO), affecting precipitation in the South Pacific convergence zone (SPCZ). These hypotheses will be tested through detailed analysis of climate and atmospheric model experiments. The model results will also be validated with observational analysis of various instrumental data and paleoclimate proxy records for the past 100-200 years. The observational analysis will show if the ITCZ and SPCZ vary independently on decadal-interdecadal time scales and how their decadal variability is associated with the decadal ENSO modulation. The results obtained from the project will not only shed light on the nature of tropical Pacific climate variability but also provide guidance in understanding the uncertainty of future ENSO behavior and in interpreting paleoclimate proxy records of ENSO.

El Nino-Southern振荡（ENSO）现象为年际时间尺度提供了气候可预测性的重要来源。该研究的目的是对通过模型实验和观察性分析对ENSO和热带太平洋十年际变异性的十年调制和热带太平洋十年变异性重要的过程的机械理解。假设北太平洋和南太平洋的随机大气变异性的低频成分，即北太平洋振荡（NPO）（NPO）和太平洋 - 南美（PSA）变异性，独立驱动热带太平洋衰老变异性。此外，由NPO驱动的热带太平洋十年变异性与ENSO相互作用，并通过平均地位间收敛区（ITCZ）的子午位移来调节其振幅。另一方面，PSA的变异性似乎驱动与太平洋十年振荡（PDO）相关的ENSO样际变异性（PDO），影响了南太平洋融合区（SPCZ）的降水。这些假设将通过对气候和大气模型实验的详细分析来检验。在过去100 - 200年内的各种工具数据和古气候代理记录的观察分析中，该模型结果还将得到验证。观察性分析将表明ITCZ和SPCZ在十年间际交往时间尺度上是否独立不同，以及它们的际变异性与际ENSO调制如何相关。从项目获得的结果不仅会阐明热带太平洋气候变化的性质，而且还提供了理解未来ENSO行为的不确定性以及解释ENSO古气候代理记录的指导。