The northern Bering Sea (NBS) and southern Chukchi Sea (SCS) contain several water masses with different characteristics that have been conventionally classified using temperature and salinity data. However, recent warming and sea ice decline can change these water properties, which suggests that classifying water masses using temperature–salinity diagrams could be problematic for this region. We used the light absorption coefficient of chromophoric dissolved organic matter (CDOM), a_CDOM, as an alternative way to classify water masses. The a_CDOM spectra of several water depths were measured in the NBS, the Gulf of Anadyr included, and SCS in July 2017 and 2018, and August 2018. Optical parameters that indicate CDOM quantity and quality, a_CDOM(350) and spectral slopes (S_275–295 and S_350–400), were calculated for each sample; water masses were classified using cluster analysis. When surface waters in the NBS and SCS are classified on the basis of the conventional method using a temperature–salinity diagram, they are mistakenly identified as Alaskan Coastal Water because of warmer temperatures. However, our cluster analysis using CDOM parameters evenly classified seven water masses with reasonable distributions. A water mass with the highest a_CDOM(350) and lowest S_275–295 was found along the coast of the Gulf of Anadyr and Alaska mainland, which suggests that freshwater originates from the Anadyr and Yukon rivers and is transported by the Anadyr Current and Alaskan Coastal Current, respectively. A CDOM-based water mass with high S_275–295, indicating CDOM degradation by ultraviolet radiation, was present at the sea surface. A water mass with low S_275–295 was found at deeper water depths and river mouths. These results suggest that classification with CDOM parameters is consistent with geographical features. In addition, we recognized a water mass with high nitrate concentrations, which is likely Anadyr Water that originates in the region from the Bering Slope to the Gulf of Anadyr. Overall, this study reveals that water mass classification using CDOM parameters is useful in coastal sea areas in which water mass mixing is complex.

白令海北部 (NBS) 和楚科奇海南部 (SCS) 包含几个具有不同特征的水团，这些水团通常使用温度和盐度数据进行分类。然而，最近的变暖和海冰减少会改变这些水的特性，这表明使用温度-盐度图对水团进行分类可能对该地区存在问题。我们使用发色溶解有机物 (CDOM) 的光吸收系数，一种_CDOM，作为对水团进行分类的替代方法。在一个_CDOM的几个水深光谱在NBS进行测定，阿纳德尔湾包括在内，并在7月2017 2018，以及2018年八月光学参数指示CDOM数量和质量，SCS一个计算每个样品的_CDOM (350) 和光谱斜率（S _275-295和S _350-400）；使用聚类分析对水团进行分类。当根据常规方法使用温度-盐度图对 NBS 和 SCS 中的地表水进行分类时，由于温度较高，它们被错误地识别为阿拉斯加沿岸水。然而，我们使用 CDOM 参数的聚类分析将七个具有合理分布的水团均匀地分类。一种水的质量具有最高一个_CDOM（350）和最低小号_275-295在阿纳德尔湾和阿拉斯加大陆沿岸发现了淡水，这表明淡水起源于阿纳德尔河和育空河，分别由阿纳德尔海流和阿拉斯加沿海海流输送。海面存在具有高S _275-295的 CDOM 基水团，表明 CDOM 被紫外线辐射降解。低S _{275–295 的}水团被发现在更深的水深和河口。这些结果表明，使用 CDOM 参数进行分类与地理特征一致。此外，我们还发现了一个硝酸盐浓度高的水团，这很可能是源自白令斜坡到阿纳德尔湾地区的阿纳德尔水。总体而言，这项研究表明，使用 CDOM 参数进行水团分类在水团混合复杂的沿海海域很有用。