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

点击翻译按钮获取中文摘要

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.