Under the possible impact of climate warming, recent changes in dry and wet spells have contributed significantly to climate-related hazards around the world. In this work, spatial and temporal variations in dry and wet spells over Canada are investigated using daily precipitation data from 1979 to 2018. The time-varying relationships between precipitation spells and large-scale climate anomalies are modeled using a nonstationary generalized extreme value (GEV) distribution and Bayesian quantile regression. Over the period 1979–2018, significant changes in dry and wet spells have been observed across Canada, particularly in the southern Canadian Prairies (CP), where both the number and duration of dry spells show positive trends. Dry and wet spells over many parts of Canada are nonstationary under the effects of the El Niño–Southern Oscillation (ENSO) and the Pacific–North American pattern (PNA), with PNA having stronger effects on annual maximum dry spells than ENSO, especially in the central CP and eastern Ontario. For western Canada, the influence of ENSO on dry spells tends to be relatively strong, especially for dry spells of high quantiles, as El Niño generally induces atmospheric moisture deficit. For central Canada, ENSO and PNA have a negative (positive) impact on the wet spell duration of low (high) quantiles. For eastern Canada, PNA is negatively correlated with the duration of wet spells, especially for wet spells of high quantiles. Therefore, a better understanding of the spatial and temporal variability in dry and wet spell return periods will be useful for the effective management of water resources, and for developing effective disaster mitigation measures against the possible social and economic impacts of climate-related hazards.

在气候变暖的可能影响下，干湿法最近的变化极大地加剧了世界范围内与气候相关的危害。在这项工作中，使用1979年至2018年的每日降水量数据调查了加拿大干湿法时空的变化。使用非平稳广义极值（GEV）来模拟降水量法则与大规模气候异常之间的时变关系。 ）分布和贝叶斯分位数回归。在1979年至2018年期间，整个加拿大，尤其是在加拿大南部大草原（CP）的干旱和潮湿季节都有明显变化，干旱季节的数量和持续时间均显示出积极的趋势。在厄尔尼诺-南方涛动（ENSO）和太平洋-北美格局（PNA）的影响下，加拿大许多地区的干湿法不平稳，其中PNA对年度最大干法的影响要大于ENSO，特别是在中部CP和安大略省东部。在加拿大西部，由于厄尔尼诺现象通常会导致大气湿度不足，因此ENSO对干旱的影响往往相对较强，尤其是对于高分位数的干旱。在加拿大中部，ENSO和PNA对低（高）分位数的湿法持续时间有负面（正面）影响。在加拿大东部，PNA与湿拼法的持续时间呈负相关，特别是对于高分位数的湿拼法。所以，