NSFGEO-NERC:Large-Scale Atmospheric Circulation Response to Oyashio Extension Frontal Variability

这份联合提案是提交给美国国家科学基金会地球科学理事会和英国国家科学基金会的。自然环境研究理事会的目标是研究西北太平洋Oyashio延伸区锋面变率如何通过积累单个天气系统与下垫面之间的相互作用来影响大尺度大气环流。大气风暴轴在西北太平洋强海洋锋上表现出局地最大强度，并由最大斜压性驱动，而最大斜压性又由海洋提供的大量热量和水汽维持。虽然在过去的十多年中，我们对海洋锋对大气平均气候影响的认识取得了重大进展，但仍有许多关键问题有待回答，特别是海洋锋变率对大气环流变率的影响。该提案的一个特别目标是揭示Oyashio Extension附近天气尺度上的当地海气相互作用及其对大尺度大气环流和气候变率的累积影响之间的联系。具体重点将放在这个环节的季节性对比的早期和后期的冬天，也是大规模的大气响应的不对称/nonlinear的温暖和寒冷的SST异常引起的北和南，分别由Oyashio扩展锋的移位。这些具有挑战性的目标将通过结合分析观测和再分析数据集和有针对性的气候模式实验来解决，这些气候模式实验使用了具有光谱元素动态核心的可变分辨率社区大气模式v.6，这是一种最先进的大气环流模式，它将在北太平洋配置一个非常高的分辨率，在全球其他地方配置一个较低的分辨率，以真实地模拟锋面空气-Oyashio Extension上的海洋相互作用以及与大尺度环流的反馈。此外，通过比较大气模拟和耦合到一维柱海洋模式的模拟，将研究局部海洋耦合的作用。

This joint proposal to U.S. National Science Foundation's Directorate for Geosciences and U.K. NaturalEnvironment Research Council aims to investigate how the Oyashio Extension frontal variability in theNorthwest Pacific Ocean influences the large-scale atmospheric circulation by accumulating theinteraction between the individual weather system and underlying ocean front. The atmospheric stormtrack exhibits the local maximum strength in the Northwest Pacific over the strong ocean fronts driven bycollocated maximum baroclinicity, which is in turn maintained by huge heat and moisture supplied by theocean. While significant advances have been achieved in the past decade or so on our understanding ofocean front's impact on the atmosphere for the mean climate, there are still many crucial questions yet tobe answered, especially related to impact of ocean frontal variability on the atmospheric circulationvariability. A particular goal of this proposal is to unveil the link between the local air-sea interaction inweather scale near the Oyashio Extension and its cumulative impact on the large-scale atmosphericcirculation and climate variability. Specific emphases will be placed on the seasonality of this link bycontrasting the early and late winter, and also the asymmetry/nonlinearity in the large-scale atmosphericresponse to warm and cold SST anomalies induced by a shift of the Oyashio Extension front to the northand south, respectively. These challenging goals will be addressed by combining analyses ofobservational and reanalysis datasets and targeted climate model experiments using the VariableResolution Community Atmosphere Model v.6 with Spectral Element dynamical-core, a state-of-the artatmospheric general circulation model, which will be configured with a very high-resolution over theNorth Pacific and lower resolution elsewhere globally to realistically simulate the frontal air-seainteraction over the Oyashio Extension as well as the feedback with the large-scale circulation at amanageable computational cost. Furthermore, the role of local ocean coupling will be investigated bycomparing the atmosphere-only simulations with those coupled to the 1-dimensional column oceanmodel.