Evaluation and projection of precipitation and temperature in a coastal climatic transitional zone in China based on CMIP6 GCMs

Changing climate has altered the trends and variability of precipitation and temperature globally and thereby increasing the risk of natural and social disasters, especially in coastal climatic transitional zones such as the Huaihe river basin (HRB). This paper applies the Empirical Quantile Mapping (EQM) method for bias correction and systematically evaluates the performance of the 30 Global climate models (GCMs) of the Coupled Model Intercomparison Project phase 6 (CMIP6) in simulating precipitation and temperature over the Huaihe river basin (HRB) for 1979-2014. A suitable multi-model ensemble subset (BMME) is selected based on the Euclidean Distance (ED) synthetic metric. Results show that in comparison to the baseline period 1995-2014, precipitation (temperature) over HRB is projected to increase at the rate of around 15 mm/decade (0.1 degrees C/decade), 16 mm/decade (0.3 degrees C/decade), 20 mm/decade (0.5 degrees C/decade), and 15 mm/decade (0.6 degrees C/decade) for the period 2015-2100, under Shared Socioeconomic Pathways SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5, respectively. In the long-term (2081-2100), the annual precipitation is projected to increase by 32%, 27%, 35%, and 26%, under the four scenarios, respectively. The temperature is projected to remain stable or slightly decrease under SSP1-2.6 (2 degrees C) and SSP2-4.5 (3 degrees C), while will keep rising and increasing by 6 degrees C under SSP5-8.5 and by 4 degrees C under SSP3-7.0 by 2100. The isotherm and isohyet are projected to shift northwest from southeastern coastal China to inland in the future, which is likely associated with the northwestward shift of the western Pacific anticyclone in summer.

Automated summary

Changing climate has increased the risk of natural and social disasters, particularly in coastal areas like the Huaihe river basin (HRB), by altering precipitation and temperature trends. This study evaluates the performance of 30 Global climate models (GCMs) in simulating HRB's precipitation and temperature from 1979 to 2014, using the Empirical Quantile Mapping (EQM) method for bias correction. The results project an increase in precipitation and temperature for the period 2015-2100, with varying rates depending on the scenarios. In the long-term, annual precipitation is projected to increase by 32-35%, while temperature is expected to either remain stable or slightly decrease under certain scenarios and increase by 4-6 degrees C under others.