HydrOlogical cYcle Understanding vIa Process-bAsed GlObal Detection, Attribution and prediction (Horyuji PAGODA)

宝塔将侧重于全球范围内大气、陆地和海洋水循环的变化。总体目标是通过基于过程的探测、归因和预测，提高对全球到区域尺度上不断变化的水循环预测的信心。科学范围优先考虑AO的主题2、1、3和4，将重点放在气候过程上，以扩大我们对区域尺度上水源/汇不确定性的原因的理解，在区域尺度上，gcm在降水、蒸发和其他与水相关的变量的预估变化方面显示出巨大的变化。这种模式的不确定性与大尺度环流模式和地表反馈过程的变化密切相关，而这些变化在不同模式之间是不同的。此外，即使在模型相互一致的地方（例如，与风暴路径和陆地表面过程有关的欧洲冬季更潮湿夏季更干燥的趋势），也不能想当然地认为与现实世界的一致性。在模式和观测之间进行定量比较的重要性怎么强调都不过分：现在有机会而且迫切需要进行研究，以了解在从全球到微观的空间尺度上驱动水循环变化的过程，并确定明显的差异是由于观测的不确定性、强迫说明中的错误还是模式的局限性。宝塔将通过将模型与观测相结合，并将具有内在不确定性和异质性的观测与强健的物理机制链相协调，以一种整体的方式采用模型分析和实验，从而实现其科学目标。检测和归因贯穿始终，以迭代的方式，始终如一地合并来自观察和模型的理解，以便隔离过程并确定因果关系。PAGODA的设计重点是控制水循环中全球到区域尺度变化的过程，特别是在十年时间尺度上（人为气候变化的时间尺度）。它涉及大气、陆地和海洋中的过程，并汇集了气候观测、气候模式以及探测和归因方面的专家。它寻求利用重要的新研究进展机会，包括新的观测数据集（如海洋盐度再分析，TRMM和SSMIS卫星产品，长降水记录），新模式（HadGEM3和高分辨率模拟的新功能），以及新的CMIP5模式的相互比较，并开发基于过程的检测，归因和预测的新方法。

PAGODA will focus on the global dimensions of changes in the water cycle in the atmosphere, land, and oceans. The overarching aim is to increase confidence in projections of the changing water cycle on global-to-regional scales through a process-based detection, attribution and prediction. The scientific scope prioritises themes 2,1,3,4 in the AO, adopting a focus on climate processes to extend our understanding of the causes of water source/sink uncertainty at the regional scale, which is where GCMs show huge variations concerning projected changes in precipitation, evaporation, and other water related variables. This model uncertainty is closely linked to shifts in large-scale circulation patterns and surface feedback processes, which differ between models. Furthermore, even where models agree with each other (for example, the suggested trend towards wetter winters and drier summers in Europe, connected to storm tracks and land surface processes), consistency with the real world cannot be taken for granted. The importance of quantitative comparisons between models and observations cannot be overstated: there is opportunity and urgent need for research to understand the processes that are driving changes in the water cycle, on spatial scales that range from global to microscopic, and to establish whether apparent discrepancies are attributable to observational uncertainties, to errors in the specification of forcings, or to model limitations. PAGODA will achieve its scientific objectives by confronting models with observations and reconciling observations, which possess inherent uncertainty and heterogeneity, with robust chains of physical mechanisms - employing model analysis and experiments in an integral way. Detection and attribution is applied throughout, in an iterative fashion, to merge the understanding from observations and models consistently, in order to isolate processes and identify causality. PAGODA is designed to focus specifically on the processes that govern global-to-regional scale changes in the water cycle, particularly on decadal timescales (the timescale of anthropogenic climate change). It addresses processes in the atmosphere, land and oceans, and brings together experts in climate observations, climate models, and detection and attribution. It seeks to exploit important new opportunities for research progress, including new observational data sets (e.g. ocean salinity reanalysis, TRMM and SSMIS satellite products, long precipitation records), new models (HadGEM3 & new capabilities for high resolution simulations), and the new CMIP5 model inter-comparison and to develop new methodologies for process-based detection, attribution and prediction.