Abstract
The primary approach to realizing long-term runoff prediction involves
combining a hydrological model with general circulation model. Previous
studies on the Source area of the Yellow River were all based on the
Coupled Model Intercomparison Project Phase 5 (CMIP5) data sets with
defects in physical mechanisms. In this paper, the Beijing Climate
Center Climate System Model (BCC-CSM2-MR) of CMIP6, which proved to
perform well in arid and semi-arid regions, will be used to drive the
Soil & Water Assessment Tool (SWAT) model and evaluate its
applicability in runoff simulation at Tang Nahai Hydrological Station
from 2011 to 2019. The occurrence of the extreme value of runoff, its
change trend, and the year of abrupt change of runoff in the four Shared
Socio-economic Pathway (SSP) scenarios (SSP1-2.6, 2-4.5, 3-7.0, and
5-8.5) during 2021-2100 were analyzed. The results show that: (1) the
runoff simulation evaluation index of SWAT driven by BCC-CSM2-MR in the
research area from 2011 to 2019 is excellent, and the runoff simulation
in the future is reliable and effective. (2) only the average annual
runoff in scenario 5-8.5 (708.5m /s) from 2021 to 2100 was significantly
higher than that in 2011-2019. Other scenarios are close to or less than
the annual runoff observed. Most importantly, the maximum and minimum
annual runoff values under the four scenarios all occurred during
2060-2080, so the attribution analysis of runoff extremum during
2060-2080 is worth further study. (3) it is necessary to evaluate
whether the existing reservoirs and hydropower stations in the Yellow
River basin can reasonably regulate and utilize the annual runoff under
scenario 5-8.5.