Diagnosing Earth's Energy Pathways in the Climate system (DEEP-C)

自20世纪70年代以来的全球变暖趋势在最近10-15年间有所减缓，尽管大气中的二氧化碳仍在不断增加（主要是由于化石燃料的燃烧）。我们提出的研究旨在了解全球变暖“中断”的原因，特别是海洋和大气通过围绕气候系统的能量运动在促成这一中断方面的作用。这将有助于我们监测气候变化，并了解使我们能够更准确地预测未来几十年气候变化的重要过程。地球变暖的原因是地球吸收的阳光和不断从地球向太空发射的热辐射能量（红外线）之间存在一种微小但持续的不平衡：如果到达地球的能量多于离开地球的能量，那么气候就会变暖。要理解升温明显减缓的原因，需要对来自太空的能量流进行详细的评估，以及这些能量是如何被大气输送、被表层海洋吸收并俯冲到海面以下深处的。此前，科学家们已经发现了这些能量流之间的差异，即气候中的“缺失能量”。这项研究计划的主要目标是解决这些能量流之间的差异，并了解地球表面变暖中断的根本原因。我们提出的项目结合了最新的、改进的地球辐射能不平衡卫星测量（反射的阳光和发射的热辐射），我们对大气中能量流的最佳估计（来自再分析模拟）和由数千个自动浮动浮标进行的详细的三维海洋加热测量，以确定观测到的气候系统中的能量流。我们将把这些测量结果与最先进的地球气候描述结合起来，通过复杂的计算机模拟来了解由于温室气体增加而积聚的能量被重新分配到海洋中的机制。大气中反射性气溶胶数量的增加（由于人类活动或火山喷发自然排放）可能减轻了地球的升温，这似乎是合理的。然而，我们的初步分析使我们得出这样的假设：事实上，更多的热量进入了深海，而不是加热了行星表面。弄清这个问题的真相对于理解当前的气候变率以及未来10年或更长时间的气候变化至关重要。我们认为，这项研究对于了解区域海平面上升（因为较暖的水占据更大的体积导致海平面上升）、云的波动以及它们是否放大或减少变暖趋势（气候反馈）和模拟海洋环流和热吸收也很重要，这对于代表未来几十年的气候变化至关重要。我们认为，这项研究只有结合三个机构（雷丁大学、南安普顿国家海洋学中心和英国气象局）的专业知识，包括卫星数据、大气和海洋的再分析、海洋测量和气候系统的计算机数值模拟。当前的行星变化是不寻常的，为了解我们的气候系统如何工作提供了及时的机会：发现全球变暖中断的原因，并了解和模拟在未来几十年里代表气候变率和变化的重要机制。

A global warming trend since the 1970s has slowed over the most recent 10-15 years despite the continuing build up of carbon dioxide in the atmosphere (due primarily to the burning of fossil fuels). Our proposed research seeks to understand the reasons for this "hiatus" in global warming and in particular the roles of the ocean and atmosphere in contributing to this hiatus through movement of energy around the climate system. This will help us monitor changes in climate and understand the processes that are important in enabling us to predict climate change more accurately over the coming decades.Warming of the planet is caused by a small yet persistent imbalance between the amount of sunlight absorbed by the Earth and the outgoing flow of thermal (infra-red) radiative energy constantly emanating from our planet to space: if more energy is arriving than leaving then the climate heats up. To understand why the heating has apparently slowed requires a detailed assessment of the flows of energy arriving from space, how this energy is transported by the atmosphere, taken up by the surface ocean and subducted deep below the sea surface. Previously, scientists had identified a discrepancy between these energy flows, or "missing energy" in the climate. A primary objective to the proposed research program is to resolve the discrepancy between these energy flows and understand the root causes of the hiatus in the warming of the Earth's surface.Our proposed project combines the latest, improved satellite measurements of Earth's radiative energy imbalance (reflected sunlight and emitted thermal radiation) with our best estimates of energy flows in the atmosphere (from reanalysis simulations) and detailed 3-dimensional ocean heating measurements made by thousands of automated floating buoys, to determine the observed flows of energy in the climate system. We will combine these measurements with state-of-the-art depictions of Earth's climate from sophisticated computer simulations to understand the mechanisms by which the build up of energy due to greenhouse gas increases is redistributed into the oceans.It is plausible that increased amounts of reflective aerosols in the atmosphere (due to human activities or naturally through emissions by volcanic eruptions) may have diminished the heating of the planet. However, our preliminary analyses lead us to the hypothesis that in fact more heat has been entering the deep ocean rather than heating the planets surface. Getting to the bottom of this question is vital for understanding current climate variability and future change over the coming 10 years or more. We consider that the research is also important for understanding regional sea level rise (since warmer water occupies a larger volume leading to rising sea level), fluctuations in clouds and whether they magnify or reduce warming tendencies (climate feedbacks) and simulating the ocean circulation and heat uptake, crucial for representing climate change over the coming decades.We consider that this research is only possible by combining the expertise from three institutions (the University of Reading, the National Oceanography Centre Southampton and the Met Office) covering satellite data, reanalyses of the atmosphere and ocean, ocean measurements and numerical computer simulations of the climate system. The current planetary changes are unusual and present a timely opportunity for understanding how our climate system works: to discover the cause of the global warming hiatus and to understand and simulate the mechanisms important in representing climate variability and change over the coming decades.