Roles of Tropical Instability Waves (TIWs) in Modulating El Nino-Southern Oscillation (ENSO)

热带不稳定波 (TIW) 在调节厄尔尼诺-南方涛动 (ENSO) 中的作用

• 批准号: 0727668
• 负责人: Rong-Hua Zhang
• 金额: $ 35.21万
• 依托单位: University of Maryland, College Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-15 至 2010-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0727668&HistoricalAwards=false
• 关键词: Roles; Tropical; Instability; Waves; TIWs

Almost all global climate models are deficient in their representations of the El Nino - Southern Oscillation (ENSO) phenomenon, in regard to its structure, intensity, and temporal evolution. Zhang and Busalacchi will test their hypothesis that these deficiencies stem from the inability of present generation of GCMs to simulate tropical instability waves (TIWs) in the ocean. TIWs are mesoscale phenomena arising from fluid dynamical instabilities of the equatorial zonal currents. The Principal Investigators (PIs) hypothesize that the sea surface temperature (SST) anomalies associated with TIWs give rise to fluctuating winds, that these winds contribute to the irregularity of ENSO, and that including a depiction of these fluctuating winds in GCMs will improve their representation of ENSO.The PIs will develop an empirical model for the atmospheric wind stress induced by TIWs. These TIW-induced winds will be applied, together with climatological winds, to an ocean model, in order to determine the rectified effect of this additional atmospheric variability upon the climate of the ocean. The TIW-induced winds will similarly be applied to a coupled atmosphere-ocean model in which ENSO variability is resolved, but not TIWs. These experiments will reveal the effect of TIWs, through the atmosphere, on the interannual variability in the tropical Pacific, as well as on the predictability of ENSO. Analyses of these experiments should reveal the mechanisms through which TIWs influence both the mean climate and ENSO variability. The PIs also will develop a high-resolution coupled atmosphere-ocean model that explicitly resolves TIWs. Finally, they will analyze output from two versions of the National Center for Environmental Prediction Climate Forecast System model (NCEP CFS), one of which has sufficient resolution to resolve TIWs. They will explore the role of TIW induced variability in causing differences in ENSO between these two models, especially its temporal irregularity. The broader impacts of this work are in the potential for applying the TIW parameterization that is developed to climate models used for climate simulation and for ENSO prediction.

几乎所有的全球气候模式在其对厄尔尼诺-南方涛动（ENSO）现象的结构、强度和时间演变的描述上都存在不足。 Zhang和Busalacchi将检验他们的假设，即这些缺陷源于当前一代GCM无法模拟海洋中的热带不稳定波（TIW）。 TIW是赤道纬向流流体动力学不稳定性引起的中尺度现象。 主要研究者（PI）假设，与TIW相关的海表温度（SST）异常引起波动风，这些风有助于ENSO的不规则性，并在GCM中包括这些波动风的描述将改善其对ENSO的代表性。PI将开发一个TIW引起的大气风应力的经验模型。 这些TIW引起的风将与气候风一起应用于海洋模型，以确定这种额外的大气变率对海洋气候的校正效果。 TIW诱导的风同样将被应用到一个耦合的大气-海洋模式，其中ENSO变率被解决，但不是TIW。 这些实验将揭示TIWs通过大气对热带太平洋年际变率以及对ENSO可预测性的影响。 这些实验的分析应揭示TIWs影响平均气候和ENSO变率的机制。 PI还将开发一个高分辨率的大气-海洋耦合模型，明确解决TIW。 最后，他们将分析两个版本的国家环境预测中心气候预测系统模型（NCEP CFS）的输出，其中一个具有足够的分辨率来解决TIW。 他们将探讨TIW引起的变率在造成这两个模式之间ENSO差异方面的作用，特别是其时间不规则性。这项工作的更广泛影响是有可能将TIW参数化方法应用于气候模拟和厄尔尼诺/南方涛动预测所用的气候模式。