An analysis of concurrent extreme events of continental precipitation and Integrated Water Vapor Transport (IVT) is crucial to our understanding of the role of the major global mechanisms of atmospheric moisture transport, including that of the landfalling Atmospheric Rivers (ARs) in extratropical regions. For this purpose, gridded data on CPC precipitation and ERA-5 IVT at a spatial resolution of 0.5° were used to analyse these concurrent events, covering the period from Winter 1980/1981 to Autumn 2017. For each season, and for each point with more than 400 non-dry days, several copula models were fitted to model the joint distribution function of the two variables. At each of the analysed points, the best copula model was used to estimate the probability of a concurrent extreme. At the same time, within the sample of observed concurrent extremes, the proportion of days with landfalling ARs was calculated for the whole period and for two 15-year sub-periods, one earlier period and one more recent (warmer) period. Three metrics based on copulas were used to analyse carefully the influence of IVT on extreme precipitation in the main regions of occurrence of AR landfall. The results show that the probability of occurrence of concurrent extremes is strongly conditioned by the dynamic component of the IVT, the wind. The occurrence of landfalling ARs accounts for most of the concurrent extreme days of IVT and continental precipitation, with percentages of concurrent extreme days close to 90% in some seasons in almost all the known regions of maximum occurrence of landfalling ARs, and with percentages greater than 75% downwind of AR landfall regions. This coincidence was lower in tropical regions, and in monsoonal areas in particular, with percentages of less than 50%. With a few exceptions, the role of landfalling ARs as drivers of concurrent extremes of IVT and continental precipitation tends to show a decrease in recent (warmer) periods. For almost all the landfalling AR regions with high or very high probabilities of achieving a concurrent extreme, there is a general trend towards a lower influence of IVT on extreme continental precipitation in recent (warmer) periods.

对大陆降水和综合水汽输送 (IVT) 的同时发生的极端事件的分析对于我们理解大气水分输送的主要全球机制的作用至关重要，包括在温带地区登陆的大气河流 (ARs) 的作用。为此，使用空间分辨率为 0.5° 的 CPC 降水和 ERA-5 IVT 的网格数据来分析这些同时发生的事件，涵盖 1980/1981 年冬季至 2017 年秋季期间。 400 多个非干旱天数，拟合了几个 copula 模型来模拟两个变量的联合分布函数。在每个分析点，使用最佳 copula 模型来估计并发极端的概率。同时，在观察到的并发极端样本中，计算了整个时期和两个 15 年子时期（一个较早时期和一个较近（较暖）时期）的登陆天数比例。基于 copulas 的三个指标被用来仔细分析 IVT 对 AR 登陆主要发生区域极端降水的影响。结果表明，并发极端事件的发生概率很大程度上受 IVT 的动态分量风的影响。登陆 ARs 的发生占 IVT 和大陆降水同时发生的极端日数的大部分，在几乎所有已知的登陆 ARs 最大发生区域的某些季节，同时极端日数的百分比接近 90%，并且百分比大于AR 登陆区域的 75% 顺风。这种巧合在热带地区较低，尤其是在季风区，百分比低于 50%。除了少数例外，登陆 AR 作为 IVT 和大陆降水同时极端驱动因素的作用在最近（温暖）时期趋于减少。对于几乎所有具有高或非常高概率同时发生极端事件的登陆 AR 区域，IVT 对近期（温暖）时期极端大陆降水的影响总体趋势较低。