Antarctic Climate Variability and Tropical Teleconnections

本研究将结合观测分析和三维全球气候模式（GCM）实验，深入了解南半球环模（SAM）的热带远相关和年代际变化。观测表明，近几十年来，以环极涡旋强度的增加为标志，SAM正极性增加。该研究将检验两种假设：厄尔尼诺-南方涛动（ENSO）与南极地区的遥相关是由南半球温带纬向风结构调制的，或者，不同的热带强迫导致遥相关的年代际变化。作为推论，SAM和ENSO反过来影响南极大陆的可降水量，从而影响冰的质量平衡。通过使用观测和GCM模拟，将对SAM和ENSO与全球遥相关和全球气候变化的联系有一个新的认识。观测研究包括对现代卫星时代动量、水分和热量输送作用的动力学研究，模式研究包括使用美国国家大气研究中心（NCAR）社区大气模式第4版（CAM4）进行的GCM模拟。这项研究的更广泛影响包括对国际极地年目标的贡献，以及研究生和研究科学家的职业发展。将编制大学讲座材料，并为哥伦布公立学校学生的讲座和实地考察提供便利。该项目将制作一个由高中生开发的网页，并将在伯德极地研究中心（BPRC）和国家冰雪数据中心存档公开可用的结果。与BPRC外联协调员的合作将为初高中学生提供数据和可视化活动，供当地一所以科学为导向的公立高中和俄亥俄州立大学的暑期项目使用。

This study will combine observational analyses and three-dimensional global climate model (GCM) experiments to gain insight to the tropical teleconnections and decadal variability of the Southern Hemisphere Annular Mode (SAM). Observations show an increasing positive polarity to the SAM in recent decades denoted by an increase in intensity of the circumpolar vortex. The study will test two hypotheses: that the teleconnection of the El Nino-Southern Oscillation (ENSO) to the Antarctic region is modulated by the zonal wind structure over the Southern Hemisphere extratropics, or alternatively, that different tropical forcing leads to decadal variability in the teleconnection. As a corollary, the SAM and ENSO in turn influence precipitable water transport over the Antarctic continent, and hence the ice mass balance. A new level of understanding of the SAM and ENSO linkages to global teleconnections and global climate change will be achieved by use of both observations and GCM simulations. The observational research includes a dynamical study of the role of momentum, moisture and heat transports during the modern satellite era, and the modeling study includes GCM simulations with the National Center for Atmospheric Research (NCAR) Community Atmosphere Model version 4 (CAM4).Broader impacts of this study include contributions to the goals of the International Polar Year, as well as career development for a graduate student and a research scientist. Material for university lectures will be developed, and lectures and field trips for students from the Columbus Public Schools will be facilitated. The project will produce a webpage developed by high school students, and will archive publicly-available results at the Byrd Polar Research Center (BPRC) and the National Snow and Ice Data Center. Collaboration with BPRC's outreach coordinator will yield data and visualization activities for middle and high school students to be used by a local science-oriented public high school and by summer programs at Ohio State University.