SGER: Teleconnection Structure and Evolution in the Coupled Model Simulations

SGER：耦合模型模拟中的遥相关结构和演化

• 批准号: 0445134
• 负责人: Sumant Nigam
• 金额: --
• 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: 2004
• 资助国家: 美国
• 起止时间: 2004-09-01 至 2006-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0445134&HistoricalAwards=false
• 关键词: SGER; Teleconnection; Structure; Evolution; Coupled

The recurrent patterns of interannual variability (teleconnections included) will be extracted from the Community Climate System Model (CCSM), the Geophysical Fluid Dynamics Laboratory (GFDL) model, and the Goddard Institute of Space Sciences (GISS), coupled simulations and closely compared with their observational counterparts, particularly, ENSO (the El-Nino-Southern Oscillation), PNA (Pacific/North American), NAO/AO (North Atlantic Oscillation/Annular Oscillation), and the Western Pacific (WP) patterns manifest during Northern winters of the present-day climate. The land/ocean surface temperature, ocean heat-content, 200 and 850 hPa geopotential, 200 hPa divergence, 1000 hPa (surface) winds, and the associated precipitation patterns will be the focus of intercomparison. The variables constitute a minimal set for monitoring the quality of simulated interannual variability; the variable choice will facilitate scrutiny of tropical-extratropical interactions, ocean-atmosphere interactions in the tropical and extratropical basins, hydroclimate variability, and of the global warming signal itself. Intercomparison of the variability patterns' mature-phase structure will be followed by comparative analysis of the pattern evolution; this should provide a quick, albeit incomplete, check on the realism of the underlying variability mechanisms in the coupled simulations. The evolution analysis will be conducted at submonthly resolution; preferably, at pentad time scales. An even more fundamental descriptor of the atmospheric general circulation is the zonally symmetric circulation, specially the zonal-mean zonal winds (U). Seemingly subtle differences in the (U) latitude-height structure can be consequential for climatological stationary waves and climate teleconnections, from modulation of wave propagation in/across the troposphere. The PIs will illustrate the dynamical significance of the inter-model variations of (U)-climatology by computing the orographic circulation response during winter, using a steady, linearized version of the atmospheric model's dynamical core (the diagnostic model). Additionally, since interannual variations of (U) in the middle-to-high latitude winters have figured prominently in recent discussions of troposphere-stratosphere interactions, specially, in context of the development of the NAO and global warming signals in the troposphere, a principal component analysis of (U) variability in the troposphere and stratosphere will be conducted. The significance of inter-model differences in the (U)-variability structures will again be illustrated through diagnostic modeling. Broader Impacts:This work will establish the baseline information for evaluating global and regional climate and water resource model projections for the 21st century. This is important information for environmental management and environmental policy decisions.

年际变化的循环模式（包括遥相关）将从社区气候系统模型（CCSM）、地球物理流体动力学实验室（GFDL）模型和戈达德空间科学研究所（GISS）中提取，耦合模拟并与它们的观测对应物，特别是 ENSO（厄尔尼诺南方涛动）、PNA（太平洋/北美）、NAO/AO（北大西洋涛动/环形涛动）、西太平洋（WP）模式在当今气候的北方冬季表现出来。陆地/海洋表面温度、海洋热含量、200和850 hPa位势、200 hPa散度、1000 hPa（地面）风以及相关的降水模式将是相互比较的重点。这些变量构成了监测模拟年际变化质量的最小集合；变量的选择将有助于审查热带-温带相互作用、热带和温带盆地的海洋-大气相互作用、水文气候变化以及全球变暖信号本身。 变异模式成熟期结构的相互比较之后将进行模式演化的比较分析；这应该可以快速（尽管不完整）检查耦合模拟中潜在可变性机制的真实性。演变分析将以次月分辨率进行；优选地，在五元时间尺度上。大气环流的一个更基本的描述是纬向对称环流，特别是纬向平均纬向风（U）。 (U) 纬度-高度结构中看似细微的差异可能会对气候驻波和气候遥相关产生影响，这些差异来自于对流层内/跨对流层的波传播的调制。 PI 将使用大气模型动力核心（诊断模型）的稳定、线性化版本，通过计算冬季的地形环流响应来说明 (U)-气候学模型间变化的动力学意义。此外，由于中高纬度冬季 (U) 的年际变化在最近对对流层-平流层相互作用的讨论中占据显着地位，特别是在 NAO 和对流层全球变暖信号的发展背景下，一个主要的将进行对流层和平流层（U）变化的成分分析。 (U)-变异性结构中模型间差异的重要性将再次通过诊断建模来说明。 更广泛的影响：这项工作将为评估 21 世纪全球和区域气候和水资源模型预测建立基线信息。这是环境管理和环境政策决策的重要信息。