Impact of climate change on the sensitivity and uncertainty of HBV hydrologic model parameters

Elucidating the impact of climate change on watershed hydrological model parameters is a fundamental scientific issue for analyzing parameter transferability and estimating future water balance components.Based on meteorological data from three global climate models (CNRM, IPSL and MRI) under the CMIP6 framework, the HBV hydrological model was used to simulate monthly runoff changes in the Ganjiang River basin from 2015 to 2100.The sensitivity and uncertainty of typical parameters controlling runoff simulation processes under climate change were quantified and evaluated.The major findings of this research are as follows: ① In scenarios where future precipitation either increases or decreases, the sensitivity of model parameters is generally higher relative to the stable precipitation scenario, with the soil module parameters (which calculate soil evapotranspiration and water content) being most sensitive.② The amount and intra-annual distribution of precipitation could influence parameters' sensitivity.③ If future climate change would significantly alter the proportions of runoff components (fast and slow flow), particularly under future scenarios of increased precipitation, more attention should be paid to the response module parameters.