4 Conclusions

The research provides a synthetical scientometric review for uncertainty analysis in hydrologic simulaation and water resources system on account of bibliographic data. In detail, the research was conducted from various orientations: characteristics of publications, cooperation of countries/territories and institutions, co-citation of schloars and references, co-occurrence of topics and keywords. Thus, some valuable insights are acquired for the current stage.
Over the past three decades, there have been approximately 2020 publications related to the uncertainty in the hydrological system, and the number has increased steadily, which indicates that this field is receiving increasing attention from scholars. Generally, the USA, China, Canada, Australia, and Germany were the first five prolific countries, at the same time, the Chinese Academy of Sciences, Beijing Normal University, University of Regina, North China Electric Power University, and Texas A&M University were the first five prolific institutions in this related field. The USA contributed greatly to the publications and cooperated with most countries/territories. The Chinese Academy of Sciences was the leading institution and had a relatively intimate relationship with other institutions.
Most studies were published in the representative journals in this field, such as the Journal of Hydrology and Water Resources Research. Arnold, Beven, and Huang were the representative scholars who made outstanding contributions to the field of uncertainty in hydrologic simulation and water resources management.
Research on the uncertainty in hydrologic simulation and water resources management covered broad subjects, such as environmental science, ecology, geology, mathematics, and chemistry. Through the keyword analysis, Uncertainty, Hydrological Simulation, Climate Change, Calibration, and Optimization were the hotspots in the research domain. Research on water quality and sensitivity analysis have been proved new topics over the years. By evaluating the co-cited network, the primary study field was determined to be hydrological simulations using the SWAT model, and this topic is becoming more and more mature.
In conclusion, this study field for the uncertainty in hydrologic simulation and water resources management is still a research front, and it needs to be further explored and improved in the following aspects. (i) The uncertainty mainly exists in the hydrologic model, further exploration of structure, parameters, and data acquisition can enhance the reliability of hydrologic prediction and decision-making. (ii) The uncertainty analysis of hydrological systems is insufficient to study the water-transforming pattern within atmospheric water, surface water, and groundwater included in the hydrological cycle, and new methods should be used to explore each link of the eco-hydrological process. (iii) As the single method was unable to meet the study of the uncertainty in the hydrological system, future research will likely focus on the establishment of coupled uncertainty analysis methods for synthetical uncertainty in hydrological model application and management. The research provides a broad perspective on uncertain study for hydrologic simulation and management. Furthermore, this study helps scholars identify influential trends and build new perspectives in the field. As a result, the scientific structure and frontiers of this research field of uncertainty in hydrological simulation and management can be extracted and generalized.