PICANTE - Processes, Impacts, and Changes of ANTarctic Extreme weather

从热浪到洪水等极端天气事件正变得更加强烈和频繁，这是气候变化的一个明显表现。在南极洲，极端天气通过加剧融化来消耗冰盖，从而提高全球海平面，或者通过加强降雪来加强冰盖，从而降低全球海平面。南极极端天气事件(AEWE)是由各种尺度上的因素驱动的复杂现象，人们对此知之甚少。在区域尺度上，它们是由高、低压系统驱动的，如天气图上看到的系统，以及大气河流--数千公里长的气流--从较低纬度带来温暖和潮湿的空气。反过来，这些天气系统是由更大范围的气候可变性模式驱动的，例如厄尔尼诺/南方涛动和环绕南极的西风强度，这些本身可能受到人类引起的气候变化的影响。Picante项目旨在改变我们对AEWE特征和驱动因素的理解，将自然气候可变性和人类影响的作用分开，并利用这些知识来预测未来AEWE对南极气候和冰架的影响。冰架特别容易受到AEWE的影响，因为它们自下而上(从温暖的海水)和自上而下(从温暖的空气)融化。较薄的冰架不太稳定，容易坍塌；这一点很重要，因为冰架阻挡了南极洲地面冰流入海洋的流动。失去冰架会导致冰盖更快地滑入海中，导致全球海平面上升。为了实现我们的目标，我们确定了符合呼吁范围的五个目标。1)使用南极洲气象站网络的观测、更广泛的观测网络(气候再分析)的内插数据和气候模型的模拟，汇编AEWE及其天气系统驱动因素和当地气候影响的综合数据集。2)使用这些数据和最先进的人工智能技术，调查不同尺度的AEWE驱动因素链的相对贡献。然后，我们将使用高分辨率气候模拟、新颖的卫星观测和冰盖表面模拟，将这些与当地对冰架稳定性的影响联系起来。3)为了了解AEWE未来的潜在分布及其影响，我们将使用一系列可能情景下的未来气候模拟，以及对冰盖表面和海洋的新模拟，以研究AEWE的变化将如何影响未来冰架稳定。4)这将自然导致确定需要改进模型以改进对AEWE及其影响的预测，特别是在当地气候、冰面和海洋模型方面。5)最后，我们留出空间来发现前所未有的极端情况。由于(1)中观察到的极端只是一个样本；在目前的气候下，可能会发生更多极端事件，可能产生前所未有的影响。政府间气候变化专门委员会预测，到本世纪末，南极洲将变暖高达5摄氏度，极端天气事件将变得更加强烈和频繁。因此，如果我们要了解这些变化对南极冰盖和全球海平面上升命运的影响，了解AEWE的原因和影响现在至关重要。

Extreme weather events, from heatwaves to flooding, are becoming stronger and more frequent in a visible manifestation of climate change. In Antarctica, extreme weather depletes the ice sheet through enhanced melting, which can raise global sea level, or strengthens the ice sheet through enhanced snowfall, which can lower global sea level.Antarctic extreme weather events (AEWE) are poorly understood and complex phenomena driven by factors across a range of scales. At the regional scale, they are driven by high and low-pressure systems, such as those seen on weather maps, and by atmospheric rivers - currents of air thousands of kilometres long - which bring warm and moist air from lower latitudes. In turn, these weather systems are driven by larger-scale patterns of climate variability, such as the El Niño/Southern Oscillation and the strength of the westerly winds encircling the Antarctic, which may themselves be affected by human-induced climate change.The PICANTE project aims to transform our understanding of the characteristics and drivers of AEWE, to disentangle the roles of natural climate variability and human influence, and to use this knowledge to predict the impact of future AEWEs on Antarctic climate and ice shelves. Ice shelves are particularly vulnerable to AEWE because they melt from both the bottom up (from warm ocean water) and the top down (from warm air). Thinner ice shelves are less stable and prone to collapse; this is important because ice shelves dam the flow of Antarctica's grounded ice into the ocean. Losing the ice shelves causes the ice sheet to slide into the sea faster, causing global sea level to rise.To achieve our aim, we have identified five objectives fit to the scope of the call.1) To compile a comprehensive dataset of AEWEs, their weather system drivers, and their local climate impacts using observations from Antarctica's weather station network, interpolated data from a wider network of observations (climate reanalysis) and simulations from climate models.2) To use these data and state-of-the-art artificial intelligence techniques, to investigate the relative contribution of the chain of drivers of AEWE across different scales. We will then use high resolution climate simulations, novel satellite observations and simulations of the ice sheet surface to connect these to local impacts on ice shelf stability.3) To understand the potential future distribution of AEWE and their impacts, we will use simulations of future climate under a range of possible scenarios together with new simulations of the ice sheet surface and ocean to investigate how changes to AEWE will affect future ice shelf stability.4) This will naturally lead to identifying model improvements needed to improve projections of AEWEs and their impacts, specifically in terms of local climate, ice surface and ocean models.5) Finally, we leave space to discover unprecedented extremes. Since the observed extremes from (1) can only represent a sample; more extreme events may be possible in the current climate, with potentially unprecedented impacts.The Intergovernmental Panel on Climate Change projects that Antarctica will warm by up to 5oC by the end of the century, and that extreme weather events will become stronger and more frequent. Understanding the causes and impacts of AEWE is therefore now critical if we are to understand the implications of these changes for the fate of the Antarctic ice sheet and global sea level rise.