Constraining the HBV model for robust water balance assessments in a cold climate

Abstract Robust projections of changes in the hydrological cycle a non-stationary climate rely on trustworthy estimates water balance elements. Additional drivers than precipitation and temperature, namely wind, radiation, humidity are known to have significant influence processes such as evaporation, snow accumulation, snow-melt. A gridded version rainfall-runoff HBV model is run at 1 × km scale for mainland Norway period 1980–2014, with following alterations: (i) implementation physically based evaporation scheme; (ii) net radiation-restricted degree-day factor snow-melt, (iii) diagnostic phase threshold temperature humidity. The combination improved forcing data alterations allowed regional calibration fewer calibrated parameters. Concurrently, modeled discharge showed equally good or better validation results previous versions constructed same domain; trend patterns, equivalent, potential compared fairly observations. Compared studies, lower values were found. suggest that more robust change studies has been obtained, although additional will be needed further constrain estimates.