Response of runoff to climate change in the Haihe River basin

The Variable Infiltration Capacity (VIC) model was used to investigate the response of runoff to climate change in the Haihe River basin(HRB). Firstly, the parameters of the VIC model were calibrated in six sub-catchments in the HRB. Secondly, using the parameter regionalization methodology, the model parameters were estimated in other parts of the HRB. Thirdly, The response of runoff to climate change in the HRB was estimated based on the hypothetical climate scenarios. The results indicated that a 2℃ increase of annual mean temperature would lead to a 6.5% decrease of runoff in the HRB. A 10% increase or decrease of annual precipitation would lead to a 26% increase or 23% decrease of runoff, respectively. A 10% increase or decrease of the percentage of precipitation in the flood season would lead to a 12% increase or 7% decrease of runoff, respectively. Spatially, under the change of temperature and/or precipitation, the runoff in the north-western HRB was more sensitive than that in the south-eastern HRB. Otherwise, under the change of the percentage of precipitation in the flood season, the runoff in the south-eastern HRB was more sensitive than that in the north-western HRB. Overall, the more precipitation, the less sensitive of runoff to precipitation and/or temperature, but the more sensitive of runoff to the percentage of precipitation in the flood season.