Future runoff simulation based on different typical climate models: a case study in the Yalong River basin.

Area of Science:

• Hydrology and Climate Science
• Environmental Modeling

Background:

• Accurate simulation of future river runoff is essential for water resource management.
• Climate change projections necessitate robust hydrological models for impact assessment.

Purpose of the Study:

• To simulate future runoff in the Yalong River Basin using calibrated hydrological models and climate projections.
• To identify optimal climate model data for hydrological impact studies.
• To analyze trends and periodicities in projected runoff under different emission scenarios.

Main Methods:

• Optimal climate model selection using Taylor diagrams and skill scores from NEX-GDDP-CMIP6.
• Parameterization and calibration of a Variable Infiltration Capacity (VIC) model using basin-specific data.
• Hydrological simulation using coupled climate and VIC models for future runoff projections (2025-2100).
• Statistical analysis including spectral analysis for wet-dry cycle identification.

Main Results:

• The calibrated VIC model demonstrated high accuracy (NSE > 0.8, error < 15%) for historical runoff simulation.
• Future runoff projections indicate significant increasing trends under SSP245 and SSP585 scenarios, with acceleration post-2069 under SSP585.
• Runoff remains seasonally concentrated (June-October ~75%), and spectral analysis revealed distinct multidecadal periodicities and oscillation modes under different scenarios.

Conclusions:

• The study provides a validated framework for simulating future river basin runoff.
• Projected increases in runoff and altered wet-dry cycles necessitate adaptive water resource management strategies.
• Understanding multidecadal periodicities is critical for long-term hydrological planning in the Yalong River Basin.