Sensitivity of Southern Hemispheric Atmospheric Structures to Tropical Forcing

该项目的目标是提高对热带对流系统如何影响高纬度南半球（SH）气候异常的季节，厄尔尼诺南方涛动（ENSO）和人为变化时间尺度的理解。 SH大气结构对热带强迫的敏感性将通过观测分析和新的模拟策略进行检查。 以下假设将被测试：SH大气结构是敏感的对流层上部和平流层下部（UTLS）的深对流流出的位置和时间，这种调制取决于季节，阶段ENSO，和长期趋势。一种新的技术，避免了模拟热带对流的复杂性，代表热带对流异常与南半球副热带UTLS的纬向外流扰动将在研究中使用。 月平均和ENSO平均的基本状态，目前（从全球分析）和2100 AD（从气候模式预测）将被用作边界条件的合奏模拟与威斯康星州大学非流体静力学模拟系统（UWNMS）。 这项工作的一个重要组成部分是整合关于热带和南极洲之间耦合的已知知识，通过专门网站上的图像和文字向公众传播。这一外联活动将有助于教育公众了解热带和南极如何在季节性、厄尔尼诺/南方涛动和人为全球变化时间尺度上相互耦合。 这项工作还将有助于减少南极洲季节性厄尔尼诺/南方涛动预测和未来气候模拟的不确定性。 这项工作有可能通过仔细分析ENSO和南极表面数据以及高分辨率UWNMS模拟来改进ENSO对南极洲影响的季节性预测。 这项工作也将提高我们对遥相关的理解，并提供副热带UTLS反气旋，天气Rossby波破碎和热带行星外波之间的关系的气候学描述。

The goal of this project is to improve understanding of how tropical convective systems influence high latitude Southern Hemisphere (SH) climate anomalies on seasonal, El Nino Southern Oscillation (ENSO), and anthropogenic change time scales. Sensitivity of SH atmospheric structures to tropical forcing will be examined through observational analysis and a new modeling strategy. The following hypothesis will be tested: SH atmospheric structures are sensitive to the location and timing of outflow from deep convection in the upper troposphere and lower stratosphere (UTLS), and this modulation depends on season, phase of ENSO, and longer-term trends. A novel technique that avoids the complexity of modeling tropical convection by representing tropical convective anomalies with meridional outflow perturbations in the SH subtropical UTLS will be utilized in the study. Monthly mean and ENSO mean basic states for the present (from global analyses) and for 2100 AD (from climate model forecasts) will be used as boundary conditions for ensembles of simulations with the University of Wisconsin Nonhydrostatic Modeling System (UWNMS). An important component of this work is to integrate what is known about coupling between the tropics and Antarctica for dissemination to the public via images and text on a dedicated website. This outreach activity will help educate the public regarding how the tropics and Antarctica are coupled on seasonal, ENSO, and anthropogenic global change time scales. This work will also help reduce uncertainty in seasonal ENSO forecasts for Antarctica and future climate simulations. This work has the potential to improve seasonal forecasting of the influence of ENSO on Antarctica, via a careful analysis of ENSO and Antarctic surface data and high resolution UWNMS simulations. This work will also improve our understanding of teleconnections and provide climatological descriptions of the relationship among subtropical UTLS anticyclones, synoptic Rossby wave breaking, and extratropical planetary waves.