Role of Two-Way Ocean-Atmosphere Interaction on Extratropical Climate Variability

海洋-大气相互作用对气候的作用 温带纬度的变化，无论是在季节内还是 在季节转换期间，将进行检查。 的焦点 拟议的研究将评估双向互动 海洋中产生的温度异常 和天气尺度瞬变活动（例如， 高压和低压系统）和相关低频流 大气中产生的模式。 结果将有助于 了解气候变化的原因和 季节性时间尺度的可预测性。 这项研究建立了 基于（1）过去研究单向强迫效应的研究 大气瞬变涡的SST异常（规定） 过程和（2）过去的工作，研究了双向 中纬度海温与大气环流相互作用 异常推断在长期多年的季节积分的一个 低分辨率大气模式耦合到一个恒定的深度混合 海洋分层。 在这些研究中，使用了高分辨率大气模式（NCAR CCM 1）将被使用，以便瞬态涡流的气候行为 可以更真实地模拟过程。 简单的混合 层海洋模式已被选择，以允许检查的方式， 重要的海洋-大气能量交换影响着 中纬度海温异常的演变 三个实验 计划：（1）100年的大气季节性整合 模式（CCM 1）使用指定的气候SST，（2）100年 CCM 1的季节性积分与恒定的50 m深度混合 层海洋（CCM 1CO）和（3）40-50年的季节整合 CCM 1耦合到恒定的50米深度的混合层海洋，但 观测到的热带SST变率的规定强迫 （CCM1CO/TROPSET）。 瞬变涡动活动的变率 （风暴轨迹）和突然的季节性变化， 将在实验1中研究SST变异性的缺失。 模型间的双向影响产生了外部引力 异常和风暴路径（以及相关的时间平均值 大气环流）将在实验2中进行研究。 的 热带SST变率的修正影响（包括El Nino周期）对中纬度海温异常和太平洋海温变率的影响 将评估热带外大气瞬变涡动活动 比较实验2和实验3的结果。 的行为 天气尺度的风暴路径将通过检查 RMS时间滤波1000 mb和500 mb高度的模型变化， 在斜压涡动动量和热通量的过程中， 大气环流季节突变的测定 将包括模型能量学的分析。 优势海温距平 模式及其与大气过程的关系将是 使用各种统计和综合分析进行检查，包括 滞后相关、奇异值分解和正则化 相关方法

The role of ocean-atmosphere interactions on climate variability in extratropical latitudes, both within the season and during transitions between seasons, will be examined. The focus of the proposed research will be on assessing the two-way interactive relationship between temperature anomalies produced in the ocean and synoptic scale transient activity (e.g. locations and paths of high and low pressure systems) and related low frequency flow patterns produced in the atmosphere. The results will aid in understanding the causes of climate variability and the potential for predictability on seasonal time scales. This research builds upon (1) past studies which investigated the one-way forced effects of SST anomalies (prescribed) on atmospheric transient eddy processes and (2) past work which investigated the two-way interaction between mid-latitude SST and atmospheric circulation anomalies as deduced in long multi-year seasonal integrations of a low resolution atmospheric model coupled to a constant depth mixed layer ocean. For these studies a higher resolution atmospheric model (NCAR CCM1) will be used so that the climatic behavior of transient eddy processes can be simulated more realistically. The simple mixed layer ocean model has been chosen to permit examination of the ways that the important ocean-atmosphere energy exchange influences the evolution of middle latitude SST anomalies. Three experiments are planned: (1) a 100-year seasonal integration of the atmospheric model (CCM1) using prescribed climatological SSTs, (2) a 100-year seasonal integration of CCM1 coupled to a constant 50 m depth mixed layer ocean (CCM1CO) and (3) a 40-50 year seasonal integration of CCM1 coupled to a constant 50 m depth mixed layer ocean but with prescribed forcing of observed tropical SST variability (CCM1CO/TROPSET). The variability of transient eddy activity (storm tracks) and abrupt seasonal shifts in circulation in the absence of SST variability wil be investigated in Experiment 1. The two-way influence between model produced extratropical anomalies and storm tracks (and the associated time mean atmospheric circulation) will be examined in Experiment 2. The modifying influence of tropical SST variability (which includes El Nino cycles) on middle latitude SST anomalies and variability of extratropical atmospheric transient eddy activity will be assessed by comparing the results of Experiments 2 and 3. The behavior of synoptic scale storm tracks will be characterized by examination of model variation in RMS time-filtered 1000 mb and 500 mb heights and in the processes of baroclinic eddy momentum and heat fluxes; the determination of abrupt seasonal changes in atmospheric circulation will include an analysis of model energetics. Dominant SST anomaly patterns and their relationship to atmospheric processes will be examined using various statistical and composite analyses including EOF, lag correlation, singular value decomposition and canonical correlation methods.