CAREER: Causes for the Indian Ocean Vertical Warming Structure and its Decadal Change during Recent Decades

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。自20世纪50年代以来，印度洋上层的变暖已被探测到，并显示出其具有复杂的垂直结构：近地表变暖伴随着热带上层温跃层变冷，而海底变暖较弱。造成这种复杂结构及其年代际变化的原因尚不清楚。该项目的总体目标是深入了解过去几十年印度洋变暖结构及其年代际变化。实现这一目标的目标是：(i)探索导致北印度洋和南印度洋表面变暖趋势的物理过程；（ii）限定和量化观测到的温跃层变冷和海底变暖减弱的原因，并估计温跃层变冷对海表温度（SST）的影响；(3)记录了垂直增温结构的年代际变化，并探讨了引起这种变化的机制。数据分析将与模型实验相结合。为了深入了解过程，将分析各种观测数据集和数据同化产品，并使用海洋环流模式（OGCM）进行一套精心设计的模式实验。线性模型也将用于提供对OGCM中发生的波浪过程的深入了解。此外，将对政府间气候变化专门委员会（IPCC）第四次评估报告（AR4）的一些气候模式的结果进行分析，并与OGCM解决方案进行比较，以期揭示人为强迫对印度洋变暖趋势的影响。学术价值：该项目将促进我们对IO复杂的垂直变暖结构是如何形成的，以及该结构如何以及为什么在年代际时间尺度上变化的科学理解，并提供新的见解。更广泛的影响：拟议项目的结果将为规划持续的实地项目提供科学指导，也可能有助于具有强烈社会需求的十年气候预测。该研究项目直接涉及研究生的专业培养。教育目标是：(i)通过与国家大气研究中心（NCAR）建立良好的多样性计划SOARS（大气研究和科学的重要机会）办公室合作，通过参与研究项目，为本科生实习生提供研究经验，以及（ii）加强科罗拉多大学（CU）的研究生教育。该教育计划的智力价值在于它在内陆州科罗拉多州的海洋学本科和研究生教育方面的进步。其成果将通过指导来自美国不同地区的实习生并传播结果，在国家和国际层面产生更广泛的影响。由于SOARS计划的目标是来自代表性不足的群体的学生，这些活动也将有助于扩大对地球科学的参与。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Warming of the upper Indian Ocean since the 1950s has been detected and shown to have a complex vertical structure: near-surface warming accompanies upper-thermocline cooling in the tropics and weaker warming underneath. Causes for the complex structure and its decadal change are unclear. The overall goal of this project is to develop an in-depth understanding of the Indian Ocean warming structure and its decadal to inter-decadal change in the past a few decades. The objectives to achieve this goal are to: (i) explore the physical processes that cause the north Indian Ocean and south Indian Ocean surface warming trend; (ii) qualify and quantify the causes for the observed thermocline cooling and weaker warming underneath, and estimate the effects of the cooling thermocline on the sea surface temperature (SST); (iii) document the decadal and inter-decadal change of the vertical warming structure, and investigate the mechanisms that cause the change. Data analysis will be combined with model experiments. Various observational datasets and data assimilation products will be analyzed, and a suite of carefully designed model experiments will be performed using an ocean general circulation model (OGCM), in order to achieve in-depth understanding of processes. A linear model will also be used to provide insight into the wave processes that occur in the OGCM. In addition, results from some climate models of the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) will be analyzed and compared to the OGCM solutions, with a hope to shed some light on the effects of anthropogenic forcing on the Indian Ocean warming trend.Intellectual merit: The proposed project will advance our scientific understanding of, and provide new insight into how the complex vertical warming structure of the IO is formed, and how and why the structure varies on decadal timescales. Broader impact: Results from the proposed project will provide scientific guidance for planning the sustained field programs, and may also contribute to decadal climate prediction, which has a strong societal need. The research project directly involves professional training of graduate students. The education objectives are to: (i) provide research experience for undergraduate interns through their participation in the research project by collaborating with the office of the wellestablished diversity program, SOARS (Significant Opportunities in Atmospheric Research and Science), at the National Center for Atmospheric Research (NCAR), and (ii) to enhance graduate education at the University of Colorado (CU). The intellectual merit of the education plan lies in its advancement in undergraduate and graduate education in oceanography in the land-locked state of Colorado. Its outcome will have broader impact at national and international levels through mentoring interns from various regions of the U.S. and by dissemination of results. Since the SOARS program targets students from under-represented groups, these activities will also contribute to broadening participation in the geosciences.