TerraMaris: The Maritime Continent - Driver of the Global Climate System

海洋大陆(MC)是位于印度洋和太平洋之间的热带岛屿群岛，人口超过4亿。它由大岛(苏门答腊岛、爪哇岛、婆罗洲岛和新几内亚岛)和许多小岛组成，还有高山。高的太阳输入使周围的海洋变暖，为大气提供了大量的水分，将整个地区变成了大气中的“锅炉箱”。深对流云每天在这些岛屿上空上升，导致平均降雨量超过每天10毫米，大约是英国降雨量的三倍。除了供应当地的农业外，降雨量还会对天气和气候产生深远的全球影响。在这些对流云中，巨大的热能通过冷凝释放到大气中。这种热源驱动着大气中巨大的、颠覆的环流：哈德利环流和沃克环流，它们进入急流，导致下游的天气和气候变化，甚至在英国上空。例如，1962/63年臭名昭著的寒冬和最近的极冷的2013年3月的起源被追溯到MC上空的大气对流。由于岛屿分布的复杂性，以及现有大气模式的根本不足(主要与其对流表示有关)，气候预报和天气预报都显示出严重的误差，特别是在模拟降雨方面。到目前为止，这些错误一直很难解决，因为对该区域缺乏适当的观测。计算能力和利用计算资源进步的大气模拟专业知识，一直不足以运行足够详细的计算机模式来解决对流过程及其相互作用，这是大气环流的基石，足够长的时间来允许更大规模的相互作用。然而，我们现在站在改变我们对MC上的大气过程的理解的尖端。计算机能力和建模技术已经取得进展，我们有能力以足够的分辨率对大气进行模拟，以准确地捕捉岛屿的复杂分布，并准确地对对流过程本身进行模拟。对此，海洋大陆国际年(2017-2020年)将在非常小的尺度上对大气和海洋进行测量，这对于评估和理解这些新模式模拟的结果是必要的。通过TerraMaris，英国将通过使用英国气象研究飞机、大气雷达、气球和岛屿上的陆基测量来观测MC上的对流过程，并使用自动水下和水面飞行器观测周围海域，从而在YMC上发挥主导作用。这一史无前例的协调观测将补充我们的国际伙伴正在进行的测量。近年来，英国和TerraMaris研究团队在开发高分辨率大气模型方面走在了前列。我们将运用所学的技能和知识来理解多尺度对流和大气环流背后的复杂机制，这些机制使得MC上的天气成为一个如此难以解决的问题。这一知识将使大气模拟方面取得突破性进展，改善MC地区的天气预报和气候预报，直接造福于该地区的大量人口。下游影响将使这些好处延伸到全球的遥远角落，改善全球和地区的中期天气预报和气候预测。

The Maritime Continent (MC) is the archipelago of tropical islands that lies between the Indian and Pacific Oceans, with a population of over 400 million. It comprises large (Sumatra, Java, Borneo, and New Guinea) and many smaller islands, with high mountains. High solar input warms the surrounding seas, which supply an abundance of moisture to the atmosphere, turning the whole region into an atmospheric "boiler box". Deep convective clouds rise up over the islands every day, leading to average rainfall rates in excess of 10 mm per day, approximately three times the rainfall rate over the UK. As well as supplying local agriculture, rain that falls over the MC has a far-reaching, global effect on weather and climate. Tremendous heat energy is released by condensation into the atmosphere in these convective clouds. This heat source drives giant, overturning circulations in the atmosphere: the Hadley and Walker cells, which feed into the jet streams and lead to weather and climate changes far downstream, even over the UK. For example, the origins of the infamous cold winter of 1962/63 and the recent very cold March of 2013 have been traced to atmospheric convection over the MC. For these reasons, the MC has been described as the engine room of the global climate system.Due to the complex nature of the distribution of the islands, and fundamental inadequacies in current models of the atmosphere (mainly related to their representation of convection), both climate predictions and weather forecasts show serious errors over the MC, particularly in their simulation of rainfall. Up until now, these errors have been extremely difficult to address, as there has been a lack of suitable observations over this region. Computing power, and the atmospheric modelling expertise to harness the advances in computing resources, has been inadequate to run computer models with sufficient detail to resolve the convective processes and their interactions, which are the building blocks of atmospheric circulation, for long enough to allow interactions with larger scales.However, we now stand on the cusp of transforming our understanding of atmospheric processes over the MC. Computer power and modelling expertise have progressed to the point where we have the capability to run simulations of the atmosphere at sufficient resolution to accurately capture the complex distribution of islands, and to accurately model the convective processes themselves. In response to this, the international Years of the Maritime Continent (YMC) field experiment (2017-2020) will make the measurements of the atmosphere and ocean at the very small scales that are needed to evaluate and understand the outputs of these new model simulations. Through TerraMaris the UK will take a leading role in YMC, by making observations of convective processes over the MC using the UK meteorological research aircraft, atmospheric radars, balloon and land-based measurements on the islands, and observing the surrounding seas using autonomous underwater and surface vehicles. This unprecedented suite of coordinated observations will complement measurements being taken by our international partners. The UK and the TerraMaris research team has led the way in developing high-resolution atmospheric modelling over recent years. We will apply the skills and knowledge learned to understand the complex mechanisms behind the multiple scales of convection and atmospheric circulations that have made the weather over the MC such a tough problem to crack. This knowledge will enable ground-breaking advances in atmospheric modelling, to improve weather forecasts and climate prediction over the MC region, with direct benefit to the substantial regional population. The downstream effects will see these benefits extend to the far corners of the globe, improving global and regional medium-range weather prediction, and climate projections.