CAREER: Understanding the Role of Oceans in the Planetry Energy Budget

职业：了解海洋在地球能源预算中的作用

• 批准号: 1455071
• 负责人: Brian Rose
• 金额: $ 54.47万
• 依托单位: SUNY at Albany
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-01 至 2021-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1455071&HistoricalAwards=false
• 关键词: CAREER; Understanding; Role; Oceans; Planetry

This is a CAREER proposal in which the research goal is to understand the roles of ocean heat transport (OHT) and ocean heat uptake (OHU) in the planetary energy budget. Here OHU refers to the transfer of heat from the ocean surface to depths at which the heat no longer longer affects the overlying atmosphere, thus effectively removing heat from the surface climate for a period of years to decades or longer. OHT refers to heat transport in which heat is removed from the surface in one region, transported by the subsurface ocean, and resurfaces in another. The role of OHU in climate change has become a topic of some interest, as increased OHU could explain the hiatus in global warming following the end of the 20th century. Further motivation for the project comes from modeling studies showing that different spatial patterns of OHU can cause different amounts of global warming suppression, even when the total heat uptake is the same. To some extent these differences can be explained in terms of regional climate feedbacks. For example the sea ice albedo feedback can play a significant role in amplifying the global warming caused by greenhouse gas (GHG) increases, but sea ice only occurs in cold regions near the poles. Removal of surface heat from high latitudes by OHU or OHT could reduce GHG-induced warming in these regions and thus reduce the amplifying effect of the sea ice albedo feedback. But previous work by the PI and others suggests that the effects of OHU and OHT cannot be entirely explained in terms of regional climate feedbacks activated to a greater or lesser extent depending on how the oceans redirect heat. In addition, the effects of OHU and OHT cannot be understood without considering the role of atmospheric energy transport. A previous study found that if OHU removes heat from the tropical oceans (or if OHT transfers heat out of the tropics), atmospheric transport of moist static energy will be quite efficient in spreading the effect beyond the tropics and evenly cooling the globe. But an equivalent heat removal in high latitudes instead produces concentrated high latitude cooling, a difference which can be explained in terms of the strong background moisture contrast between the warm tropics and the cold poles. The work is primarily concerned with the ocean's role in current and future climate change, but it will also consider the role of OHT in producing past climates in which the temperature contrast between low and high latitudes was reduced, such as occurred in the Phanerozoic and early Eocene. The research will also consider the response of the hydrological cycle to OHU and OHT, with a focus on the subtropics. Past work suggests that while global warming simulations often find subtropical drying, subtropical warming due to OHT can produce the opposite effect. Thus OHT could counteract GHG-induced drying to the extent that heat absorbed by the tropical oceans is transported to the subtropics, a potentially relevant effect given recent results relating the warming hiatus to OHU in the equatorial Pacific.The research agenda for the project has two key components. First, much of the work will be conducted using simplified climate models in which the ocean component model is replaced by a "slab ocean", which can absorb heat and interact thermally with the atmosphere, but which cannot transport heat. In this context heat OHT and OHU are externally imposed in the form of heat sources and sinks applied to regions where OHT converges and diverges, and where heat is sequestered in the deep ocean. Such external forcing is commonly used and is generally referred to as Q-flux forcing. The experiments allow the feedbacks and atmospheric transports to be examined in isolation, without the complications introduced by an interactive ocean. Second, the results of such experiments are often model dependent, and thus an ensemble of models is required to determine which aspects of the response to imposed OHT and OHU forcing are robust. To address this issue, the PI will organize a model intercomparison project (MIP), in which a common set of experiments will be performed using several different models. Some experiments will be performed by the PI, but he will also solicit contributions to the MIP by other researchers. Further research will include an examination of global warming simulations from state-of-the-art climate models in the Coupled Model Intercomparison Project version 5 (CMIP5), as well as perturbed physics sensitivity experiments with a single slab ocean climate model.The educational component of this CAREER project is centered on the development of a flexible climate modeling and analysis package in the Python language. The educational activity is intended to address the lack of computing skills commonly found among undergraduate and graduate students enrolled in atmospheric science departments. Specific tasks are 1) to develop a short introductory course in practical scientific computing in the Python language; 2) to develop a modular Python-based climate modeling and analysis toolkit; and 3) to develop a series of interactive educational modules illustrating fundamental principles of climate and atmospheric science. Several factors motivate the choice of Python as the language of choice, including its inherent modularity, its ability to serve as a "wrapper" for compiled Fortran and C codes, thereby promoting seamless use of established codes, and the numerous visualization and software development tools available for the language. The software to be developed will be open source, freely available online, and well documented. It will consist of a number of simplified dynamical core and process models (for radiative transfer, boundary layer turbulent fluxes, etc.), which can be integrated alone or combined in various ways to form simple a simple climate model. In addition to the on-campus teaching activities, Python-based modules will be developed for use in a summer camp for local high school students.

这是一项职业提案，其研究目标是了解海洋热传输（OHT）和海洋吸热（OHU）在行星能量预算中的作用。这里的OHU是指热量从海洋表面转移到热量不再影响上覆大气的深度，从而在数年至数十年或更长时间内有效地从表面气候中去除热量。 OHT 是指热传输，其中热量从一个区域的表面被带走，通过地下海洋传输，并在另一区域重新出现。 OHU 在气候变化中的作用已成为人们感兴趣的话题，因为 OHU 的增加可以解释 20 世纪末后全球变暖的中断。该项目的进一步动机来自于模型研究，该研究表明，即使总吸热量相同，不同的 OHU 空间模式也会导致不同程度的全球变暖抑制。 在某种程度上，这些差异可以用区域气候反馈来解释。 例如，海冰反照率反馈可以在放大温室气体（GHG）增加引起的全球变暖方面发挥重要作用，但海冰只出现在两极附近的寒冷地区。 通过 OHU 或 OHT 去除高纬度地区的地表热量可以减少温室气体引起的这些地区的变暖，从而减少海冰反照率反馈的放大效应。 但 PI 和其他人之前的工作表明，OHU 和 OHT 的影响不能完全用区域气候反馈来解释，区域气候反馈的激活或多或少取决于海洋如何重新引导热量。此外，如果不考虑大气能量传输的作用，就无法理解 OHU 和 OHT 的影响。 先前的一项研究发现，如果 OHU 消除热带海洋的热量（或者如果 OHT 将热量转移出热带地区），湿静态能量的大气传输将非常有效地将效应传播到热带地区以外，并均匀地冷却全球。 但高纬度地区同等的热量去除反而会产生集中的高纬度冷却，这种差异可以用温暖的热带地区和寒冷的两极之间强烈的背景湿度对比来解释。这项工作主要关注海洋在当前和未来气候变化中的作用，但也会考虑 OHT 在产生过去气候中的作用，在过去的气候中，低纬度和高纬度之间的温度差异减小，例如发生在显生宙和早期。始新世。 该研究还将考虑水文循环对 OHU 和 OHT 的响应，重点关注亚热带地区。 过去的研究表明，虽然全球变暖模拟经常发现亚热带干燥，但 OHT 导致的亚热带变暖可能会产生相反的效果。 因此，OHT 可以抵消温室气体引起的干燥，因为热带海洋吸收的热量被输送到亚热带，考虑到赤道太平洋变暖中断与 OHU 相关的最新结果，这是一个潜在的相关影响。该项目的研究议程有两个关键部件。 首先，大部分工作将使用简化的气候模型进行，其中海洋成分模型被“板状海洋”取代，“板状海洋”可以吸收热量并与大气发生热相互作用，但不能传输热量。 在这种情况下，热量 OHT 和 OHU 以热源和热汇的形式从外部强加，应用于 OHT 汇聚和发散的区域以及热量被隔离在深海中的区域。 这种外部强迫是常用的并且通常被称为Q-通量强迫。 这些实验可以单独检查反馈和大气传输，而不会出现交互式海洋带来的复杂情况。 其次，此类实验的结果通常依赖于模型，因此需要一组模型来确定对强加的 OHT 和 OHU 强迫响应的哪些方面是稳健的。 为了解决这个问题，PI 将组织一个模型比对项目 (MIP)，其中将使用几个不同的模型进行一组通用的实验。 一些实验将由 PI 进行，但他也会征求其他研究人员对 MIP 的贡献。进一步的研究将包括对耦合模型比对项目第 5 版 (CMIP5) 中最先进的气候模型的全球变暖模拟进行检查，以及使用单个板状海洋气候模型进行扰动物理敏感性实验。该 CAREER 项目的重点是使用 Python 语言开发灵活的气候建模和分析包。 该教育活动旨在解决大气科学系本科生和研究生普遍缺乏计算技能的问题。 具体任务是1）用Python语言开发实用科学计算的简短入门课程； 2）开发基于Python的模块化气候建模和分析工具包； 3) 开发一系列互动教育模块，阐释气候和大气科学的基本原理。 选择 Python 作为首选语言有几个因素，包括其固有的模块化性、作为已编译的 Fortran 和 C 代码的“包装器”的能力，从而促进已建立代码的无缝使用，以及众多的可视化和软件开发工具可用于该语言。 待开发的软件将是开源的，可以免费在线获取，并且有详细的文档记录。它将由许多简化的动力核心和过程模型（用于辐射传输、边界层湍流通量等）组成，这些模型可以单独集成或以各种方式组合以形成简单的气候模型。 除了校内教学活动外，还将开发基于Python的模块，供当地高中生夏令营使用。