Hydrological simulation and prediction of the Jinghe River Basin based on CMIP6 climate scenario

Abstract

[Purpose]The land use change caused by climate change and human activities brings challenges to water resources regulation and management, which makes it a current research need to explore the hydrological simulation process under the influence of both and make quantitative prediction and analysis. [Methods] Based on three climate models of CMIP6, namely ACCESS-CM2, BCC-CSM2-MR, and Nor ESM2-LM, two concentration scenarios SSP245 and SSP585 were used to simulate the precipitation, minimum temperature, and maximum temperature of the Jinghe River Basin in the future period(2022—2044)after deviation correction; Based on the land use data of the watershed in 2005 and 2015, the CA-Markov model is used to predict the spatial distribution of land use in the watershed in 2025. Combined with climate model data, the SWAT distributed hydrological model is driven to predict future runoff changes in the Jinghe River Basin and analyze the impact of two factors on the rate of runoff change. [Results] The research result indicate that:(1) In the future period(2022—2044), under the SSP245 and SSP585 scenarios, the annual average precipitation will increase by 0. 3% and 1. 41% compared to the reference period(2006—2012), with the lowest temperature increasing by 0. 9 ℃ and 1. 11 ℃, and the highest temperature increasing by 0. 28 ℃ and 0. 07 ℃, respectively.(2) In 2025, the area of construction land and arable land increased by 34. 97% and 3. 15% respectively compared to 2005, while the area of grassland and forest land decreased by 4. 30% and 1. 59%.(3) The R² and NSE values of the simulated and measured runoff values during the reference period and validation period are 0. 86 and 0. 7,0. 76 and 0. 71, respectively, with R² greater than 0. 7 and NSE greater than 0. 65.(4) The simulated annual average runoff values for the four scenarios(S45_ LUC05, S85_ LUC05, S45_ LUC25, S85_LUC25) are 387 m³/s, 387. 87 m³/s, 419. 17 m³/s, and 422. 94 m³/s, respectively. [Conclusion] (1) In the future(2022—2044), the average annual precipitation and temperature in the Jinghe River Basin will show an overall upward trend.(2) In the future period(2025), the construction land area of the Jinghe River Basin will significantly increase, while the grassland and forest area will show a decreasing trend.(3) The SWAT model has good applicability in hydrological simulation of the Jinghe River Basin.(4) Under the four scenarios, future runoff will show an upward trend, Climate and land use change jointly affect runoff change, and the impact of land use change on runoff is greater than that of climate factors.

Keywords

CMIP6 / SWAT model / land use / runoff simulation / Jinghe River Basin / climate change / precipitation