High-resolution in situ water level data are one of the core sources for the identification and understanding the reaction of the sea to climate change. We analyse digitized recordings of water level measurements from all 10 currently functioning coastal tide gauges on the Latvian shores of the Baltic proper and in the Gulf of Riga for the period 1961–2018. The frequency and temporal coverage of measurements vary greatly for these stations. The most complete hourly data are available from Liepaja on the Baltic proper coast and from Daugavgriva in the south-eastern bayhead of the Gulf of Riga. The water level regime is analysed from the viewpoint of (i) the entire range of water level variations, (ii) empirical probability distributions of different water levels, (iii) the seasonal course of water level, (iv) trends in the annual, seasonal, and monthly means and extremes of water level (in terms of the relative and uplift corrected absolute values), and (v) correlations of the main properties of water level with the North Atlantic Oscillation (NAO Gibraltar) index.

The empirical probability distributions of different water levels have become narrower 1991–2018 compared to 1961–1990 whereas very low water levels are now less frequent. The amplitude of the seasonal course has greatly decreased over these time intervals. The annual mean and maxima of water level have increased 1961–2018. The rate of increase is smaller than the rate of increase in the sea level in the North Atlantic suggesting that changes in the local drivers of water level mitigate the sea level rise in Latvian waters. Variations in the NAO index can explain 1/3 of the annual variability of the main properties of water level and up to 2/3 of this variability in wintertime (December–March). The changes in the statistical properties of water level are consistent with alterations to the directional structure of strong winds.

高分辨率的原位水位数据是识别和了解海洋对气候变化的反应的核心来源之一。我们分析了1961-2018年期间波罗的海拉脱维亚沿岸和里加湾所有10个当前运行的沿海潮汐水位的数字化记录。这些电台的测量频率和时间覆盖范围相差很大。可从波罗的海沿岸的利耶帕亚和里加湾东南湾的陶格夫格里瓦获得最完整的小时数据。从（i）水位变化的整个范围，（ii）不同水位的经验概率分布，（iii）水位的季节性变化，（iv）年度趋势，季节性

与1961-1990年相比，不同水位的经验概率分布在1991-2018年变得更窄，而现在非常低的水位已经不那么频繁了。在这些时间间隔内，季节性过程的幅度已大大降低。1961-2018年，年平均水位和最高水位增加了。上升速度小于北大西洋海平面上升速度，这表明当地水位驱动因素的变化减轻了拉脱维亚水域的海平面上升。NAO指数的变化可以解释水位主要特征的年度变化的1/3，而冬季（12月至3月）则高达这种变化的2/3。水位统计特性的变化与强风的定向结构的变化一致。