Climate change is increasingly affecting the water cycle and as freshwater plays a vital role in countries’ societal and environmental well-being it is important to develop national assessments of potential climate change impacts. Focussing on New Zealand, a climate-hydrology model cascade is used to project hydrological impacts of late 21st century climate change at 43,862 river locations across the country for seven hydrological metrics. Mean annual and seasonal river flows validate well across the whole model cascade, and the mean annual floods to a lesser extent, while low flows exhibit a large positive bias. Model projections show large swathes of non-significant effects across the country due to interannual variability and climate model uncertainty. Where changes are significant, mean annual, autumn, and spring flows increase along the west and south and decrease in the north and east. The largest and most extensive increases occur during winter, while during summer decreasing flows outnumber increasing. The mean annual flood increases more in the south, while mean annual low flows show both increases and decreases. These hydrological changes are likely to have important long-term implications for New Zealand’s societal, cultural, economic, and environmental well-being.

中文翻译：

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21世纪后期气候变化下的新西兰河流水文

气候变化对水循环的影响越来越大，由于淡水在各国社会和环境福祉中发挥着至关重要的作用，因此对潜在的气候变化影响进行国家评估非常重要。以新西兰为重点，使用气候水文模型级联来预测 21 世纪后期气候变化对全国 43,862 个河流位置的水文影响，以获得七个水文指标。平均年和季节性河流流量在整个模型级联中得到了很好的验证，年平均洪水的程度较小，而低流量则表现出很大的正偏差。模型预测显示，由于年际变率和气候模型的不确定性，全国范围内存在大量非显着影响。在变化显着的地方，平均每年、秋季、春季流量沿西部和南部增加，北部和东部减少。最大和最广泛的增加发生在冬季，而在夏季减少流量超过增加。年平均洪水在南部增加较多，而年平均低流量则有增有减。这些水文变化可能对新西兰的社会、文化、经济和环境福祉产生重要的长期影响。