Impact of Atmospheric 30-60 Day and Quasi-biweekly Oscillation on Tropical Indian Ocean Dynamics, Heat Transport, and Upper Ocean Heat Content

热带印度洋大气季内振荡（ISOs）的气候重要性已受到越来越多的关注。反映这一重要性的是，广泛的模拟研究以及一些新部署的系泊观测，在过去几年中大大提高了我们对大气iso引起的印度洋变率的各个方面的理解。然而，这种理解还远远不够完整，许多突出的科学问题仍未得到解决。该项目的目标是探索：(i)赤道印度洋的地表和地下经向流如何以及为什么对大气iso（特别是占主导地位的30-60天和准双周振荡）做出响应，以及这种响应如何影响跨赤道热输送的多时间尺度变率？（ii）上层印度洋对大气iso响应的季节性和年际变化是什么？（三）大气iso如何影响热带印度洋（特别是暖池）热含量的变率？这个项目的主要工具是海洋环流模型。卫星数据结合来自欧洲中期天气预报中心的每日再分析将被用作强迫场模式。海洋模型中物理的现实表现允许对海洋如何响应季节内大气强迫进行直接调查。为了深入了解所涉及的关键海洋过程，还将使用线性连续分层模型和非线性中间海洋模型。将对印度洋现有数据进行分析、比较，并用模型解决方案进行解释。所提出的研究具有重要的科学意义，因为对热带印度洋（独立于ENSO的部分）的年际变率还没有很好地了解，并且已经提出了大气iso的跨时间尺度影响。该项目涉及气候研究的一个中心主题，对于理解大气iso在引起热带地区多尺度气候变化中的作用至关重要。拟议项目的智力价值在于它有助于增进我们对热带印度洋如何以及为什么对季节内大气强迫作出反应的理解，并提供新的见解，这项研究将为确定大气iso在引起热带海洋/大气耦合系统气候变率方面所起的作用奠定坚实的基础。通过将研究与教育相结合，该项目将通过推进气候研究和促进研究生教育，对我们的社会产生更广泛的影响。

0452917The climatic importance of atmospheric IntraSeasonal Oscillations (ISOs) in the tropical Indian Ocean has been receiving increasing attention. Reflecting this importance, extensive modeling studies, together with a few newly deployed mooring observations, have significantly advanced our understanding of various aspects of Indian Ocean variability induced by atmospheric ISOs in the past a few years. This understanding, however, is far from complete and many outstanding science issues remain unaddressed.The objectives of the proposed project are to explore: (i) How and why do the surface and subsurface meridional currents in the equatorial Indian Ocean respond to atmospheric ISOs (especially the dominant 30-60 day and quasi-biweekly oscillations), and how does that response impact multi-timescale variability of cross-equatorial heat transport? (ii) What are the seasonality and interannual variability of the upper Indian Ocean response to atmospheric ISOs? (iii) How do atmospheric ISOs affect the variability of tropical Indian Ocean (especially the warm pool) heat content?The primary tool for this project is an ocean general circulation model. Satellite data combined with daily reanalysis from the European Center for Medium range Weather Forecasts will be used as the model forcing fields. The realistic representation of physics in the ocean model allows for a direct investigation of how the ocean responds to the intraseasonal atmospheric forcing. To provide insights into the key oceanic processes involved, a linear continuously stratified model and a nonlinear intermediate ocean model will also be used. Available data in the Indian Ocean will be analyzed, compared with, and interpreted by the model solutions. The proposed research is scientifically important because interannual variability of the tropical Indian Ocean (the part that is independent of ENSO) is not well understood, and the cross-timescale impact of atmospheric ISOs has been suggested. The project addresses a central theme of climate research and is essential for understanding the role of atmospheric ISOs in causing multi-scale climate variability in the tropics. The intellectual merit of the proposed project lies in its contribution to advancing our understanding of, and providing new insight into, how and why the tropical Indian Ocean responds to intraseasonal atmospheric forcing, a study that will build a solid foundation for identifying the role played by atmospheric ISOs in causing climate variability in the tropical coupled ocean/atmosphere system. By integrating the research with education, the project will have a broader impact on our society through both advancing climate research and promoting graduate education.