Abstract:

Mountainous alpine areas are important water−producing areas in inland river basins that are highly sensitive to climate change. This study explored the projected changes in precipitation, maximum temperature (Tmax) and minimum temperature (Tmin) in the Tailan river basin (TRB) based on 14 Global Climate Models (GCMs) from the coupled model intercomparison project phase 6 (CMIP6) and the multi−model ensemble (MME) of the bias−corrected dataset by Delta method during 2081−2100, with reference to the baseline period 1995−2014, under three integrated scenarios (SSP1−2.6, SSP2−4.5, and SSP5−8.5) of Shared Socioeconomic Pathways (SSPs) in order to understand precipitation and temperature changes over TRB and provide references for local strategies against climate change. The results showed that: (1) the biases between CMIP6 GCMs and observation value could be effectively corrected by DCM. Meanwhile, it was found that the MME was better than all other individual models for each climatic variable. (2) Precipitation,Tmax,Tmin over the TRB from 2025 to 2100 was projected to increase under SSP1−2.6, SSP2−4.5 and SSP5−8.5. Precipitation was projected to increase at the rate of 6.51mm·10y⁻¹, 8.81mm·10y⁻¹ and 9.01mm·10y⁻¹ under SSP1−2.6, SSP2−4.5, and SSP5−8.5, respectively. Tmax was projected to increase at the rate of 0.09℃·10y⁻¹, 0.16℃·10y⁻¹ and 0.42℃·10y⁻¹ under SSP1−2.6, SSP2−4.5 and SSP5−8.5, respectively. Tmin was projected to increase at the rate of 0.09℃·10y⁻¹, 0.17℃·10y⁻¹ and 0.43℃·10y⁻¹ under SSP1−2.6, SSP2−4.5 and SSP5−8.5, respectively. (3) During 2081−2100, both precipitation and temperature over TRB increased under three integrated scenarios (SSP1−2.6, SSP2−4.5 and SSP5−8.5). The annual precipitation was projected to increase by 7.84−11.45pp, 18.45−21.35pp and 20.20−24.02pp under SSP1−2.6, SSP2−4.5 and SSP5−8.5, respectively. The annual mean Tmax over the TRB was projected to increase by 2.03−2.07℃, 2.95−3.02℃ and 5.07−5.12℃ under SSP1−2.6, SSP2−4.5 and SSP5−8.5. The annual mean Tmin over the TRB was projected to increase by 1.85−1.92℃, 2.99−3.04℃ and 6.09−6.13℃ under SSP1−2.6, SSP2−4.5 and SSP5−8.5.

Key words: Tailan river basin (TRB), CMIP6, Delta method, Multi?model ensemble (MME)