Naturalized daily discharge data for major river gauges in Yenisei river basin (1956-2019)

We introduce a new Arctic daily discharge data set covering 8 major gauges in the Yenisei drainage basin, largest in the pan-Arctic. All gauges are under significant influence of reservoir regulation. The data file includes two types of discharge data: 1) observed daily discharge values officially published by Roshydromet and 2) modeled “naturalized” daily discharge. The “naturalized” discharge means discharge values with excluded human impact. The naturalized data were used along with tree-ring data to reconstruct long-term annual discharge records. The data can be used in hydro-climatological analysis to understand interactions between climate and hydrology. A specially developed Hydrograph Routing Model (HRM) was used to eliminate effects of reservoirs and other human impact from discharge records. The model routes observed daily hydrographs from unregulated upstream gauges in the downstream direction using a Duhamel integral approach and ‘naturalizes’ the river flow (1956-2019). This method provides more accurate hydrograph simulations than water balance modelling approaches for hydrograph simulation as it uses only observed river discharge which is the most accurately measured component of the hydrological cycle. The HRM was tested over the unregulated period (before 1957) and showed good results for all reconstructed gauges in the Yenisei basin.

本研究提出一套全新的北极地区日径流量数据集，涵盖泛北极最大流域——叶尼塞河流域内的8处主要水文测站。所有测站均受到水库调度的显著影响。该数据集包含两类径流量数据：1）由俄罗斯水文气象局（Roshydromet）正式发布的实测日径流量数据；2）经模型模拟得到的“天然化”日径流量数据。所谓“天然化”径流量，即剔除人类活动影响后的径流量数值。天然化径流量数据与树木年轮数据结合，被用于重建长期年径流量序列。该数据集可用于水文气候学分析，以揭示气候与水文之间的相互作用机制。研究团队通过专门开发的河道汇流模型（Hydrograph Routing Model, HRM），去除了径流量记录中的水库调度及其他人类活动干扰。该模型采用杜哈梅积分法，沿下游方向对未受调控的上游测站的实测日流量过程线进行汇流演算，从而实现1956-2019年时段内的河道径流天然化处理。相较于水文过程模拟常用的水量平衡模型方法，该方法仅使用水文循环中观测精度最高的河道径流量数据，因此可实现更为精准的流量过程线模拟。河道汇流模型（HRM）在1957年之前的未受调控时段进行了验证，结果显示其在叶尼塞河流域所有经重建的水文测站的模拟效果均表现良好。