Response of runoff and its components to climate change and its future trend in the source region of the Yangtze River

• Published in: Hydrological processes 2024-06, Vol.38 (6), p.n/a
• Main Authors: Gao, Tailai, Li, Jiadi, Tang, Yuanzhi, Jiang, Xiaoxuan, Huo, Junjun
• Format: Article
• Language: English
• Subjects: Ablation; Base flow; Climate change; Climate models; Climate prediction; CMIP6 climate model; Components; Glacial ablation; Glacial runoff; Glacier melting; Glaciers; Glaciohydrology; Global climate; Hydrologic models; Hydrology; Precipitation; Rainfall; Rainfall runoff; Rainfall-runoff relationships; Resource management; Rivers; Runoff; runoff simulation; Snowmelt; Snowmelt runoff; the spatial processes in hydrology model; the Yangtze River source; Water conservation; Water resources; Water resources management
• ISSN: 0885-6087; 1099-1085
• DOI: 10.1002/hyp.15180

Under global climate changes, the temperature and precipitation on the Tibetan Plateau changed significantly, causing accelerated melting of glaciers and snow and changes in runoff. The response of runoff and its components to climate change is important for water resource management and ecology conservation in the region. Therefore, the Spatial Processes in Hydrology model, a distributed cold‐zone hydrological model that contains a glacial ablation module, was used to simulate runoff in the Yangtze River source located in the middle of the Tibetan Plateau during 2000–2050, and the Nash‐Sutcliffe efficiency coefficient, relative error and coefficient of determination (R2) for the calibration period and validation period revealed that the model performed well in most years. The results showed that rainfall runoff contributed the most to the total runoff (61%), followed by baseflow (23%), snowmelt runoff (12%) and glacier runoff (4%) in the Yangtze River source during 2000–2020. The runoff amounts of the three source rivers, Dangqu River, Tuotuo River and Chumar River, accounted for approximately 53% of the total runoff in the Yangtze River source basin, with rainfall runoff (52%) contributing the most and glacier runoff (6%) contributing the least. Compared to the contributions of glacial runoff in the Dangqu River (9%) and Tuotuo River (7%), the proportion of glacial runoff in the Chumar River is small (1%). Under the CMIP6 climate model, the mean runoff depth is predicted to increase by approximately 13.5 mm from 2020 to 2050 compared with that from 2000 to 2020. A distributed cold‐zone hydrological model, the Spatial Processes in Hydrology model, was used to simulate runoff in the Yangtze River source. The calibration and validation of model parameter used runoff data from Zhimenda hydrological station. In 2000–2020, rainfall runoff contributed most to the total runoff (60.87%) in the Yangtze River source, followed by baseflow (22.96%), snowmelt runoff (11.59%) and glacier runoff (4.58%). Under the CMIP6 climate model, the mean runoff depth increases 13.5 mm during 2020–2050.