MEZCAL - Methods for Extending the horiZontal Coverage of the Amoc Latitudinally and retrospectively

AMOC是一个大规模的海洋循环系统，由洋流组成，洋流将温暖的浅水带到北方，将寒冷的深水送到南方。AMOC对于维持欧洲西北部相对温和的冬季气候至关重要。AMOC的关闭将严重影响欧洲的温度和降水变化。由于AMOC在调节全球气候系统方面的作用，已经建立了几个直接海洋观测计划来监测AMOC。在北大西洋，两个主要观测阵列分别是北纬26度和北纬50-60度的快速气候变化方案(RAPID)和亚极地北大西洋方案(OSNAP)的翻转。虽然这些计划改变了我们对AMOC变化的理解，但它们仅限于单一的纬度线，寿命相对较短(最多20年)。这些限制使我们无法理解长期(十年到百年)时间尺度上的变化，也无法理解AMOC是如何跨越我们没有直接测量的纬度连接起来的。此外，观测阵列的维护费用很高，而且在仪器发生故障或丢失的情况下没有备用系统。为了克服快速和OSNAP观测阵列的限制，海洋界寻求了使用具有成本效益的观测系统监测AMOC的替代解决方案，如现有的卫星和自主海洋机器人数据，这些系统具有较高的空间和时间覆盖率。这些监测AMOC的替代解决方案最近在北大西洋的几个地方进行了试验。与此同时，机器学习和建模方法的进步开始被证明对间接测量的AMOC监测有用。RAPID和OSNAP的AMOC监测不久将分别实现20年和10年的连续测量。这些AMOC记录与替代AMOC监测方法的最新发展相结合，意味着海洋学界现在已经有了适当的工具，可以极大地提高我们在很长一段时间内了解北大西洋AMOC的能力。因此，MEZCAL将把计算上的进步与最近被证实的监测AMOC的替代方法结合起来，以扩大AMOC观测的覆盖范围，并提供一个新的框架，使我们对AMOC可变性的理解发生重大变化。该项目还将为今后如何建立可持续的AMOC监测系统提供建议。

The AMOC is a large-scale ocean circulation system composed of currents that carry warm, shallow water northwards and return cold, deeper water southwards. The AMOC is crucial in maintaining the relatively mild winter climate of north west Europe. A shutdown of the AMOC would strongly impact European temperature and precipitation variability.Because of the AMOC's role in regulating the global climate system, several direct ocean observing programmes have been put in place to monitor the AMOC. In the North Atlantic, the two main observing arrays are the Rapid Climate Change Programme (RAPID) and the Overturning in the Subpolar North Atlantic Program (OSNAP) at 26N and 50-60N, respectively. While these programmes have transformed our understanding of changes in the AMOC, they are limited to single lines of latitude and have relatively short lifespans (two decades at most). These constraints prevent us from being able to understand changes on long (decadal to centennial) timescales or understand how the AMOC is connected across the latitudes where we don't have direct measurements. Further, the maintenance of the observing arrays is costly and there is no backup system in place in the event of instrumentation failure or loss.To overcome the limitations of the RAPID and OSNAP observing arrays, the oceanographic community has sought alternative solutions for monitoring the AMOC using cost-effective observing systems, like existing satellite and autonomous ocean robot data that have high spatial and temporal coverage. These alternative solutions for monitoring the AMOC have recently been trialled at a few places in the North Atlantic. At the same time, advances in machine learning and modelling methods are starting to prove useful for monitoring the AMOC from indirect measurements.The AMOC monitoring at RAPID and OSNAP will soon achieve 20- and 10- years worth of continuous measurements, respectively. The combination of these AMOC records with the recent developments in alternative AMOC monitoring methods means that the oceanographic community now has the tools in place to dramatically improve our ability to understand the AMOC across the North Atlantic Ocean over long time periods. Thus, MEZCAL will combine computational advances with the recent proven alternative methods for monitoring the AMOC to extend the coverage of AMOC observations across the North Atlantic and deliver a new framework that will make a step change in our understanding of AMOC variability. This project will also provide recommendations for how to build a sustainable AMOC monitoring system moving forward.