Attributing the streamflow variation by incorporating glacier mass balance and frozen ground into the Budyko framework in alpine rivers

The remarkable climate change has profound impact on the alpine hydrology, it remains unclear to date on the role of the changes in glacier and frozen ground degradation to the regional streamflow variation. Here, we incorporated the glacier mass balance and frozen ground degradation into the Budyko framework and used the elasticity method to attribute the variation of annual streamflow for 22 rivers in Qilian Mountains (QLM) from 1982 to 2015. The results indicates the simulated annual streamflow that considering glacier mass balance and frozen ground can explain more than 90% of observed streamflow at a significance of p < 0.01, especially for the rivers with high glacier coverage. The elasticity method revealed the simulated streamflow variation can explain more than 91% of variation in respect to the detected streamflow variation. It indicates the robust of the elasticity method and highlights the ability of capture the variation in streamflow with the Budyko framework that incorporated glacier mass balance and frozen ground. There were 3 classifications was clustered and the contribution of precipitation to streamflow variation in the 3 classifications were consistency to the streamflow variation in the 22 rivers of QLM. The precipitation play as a dominant role for the streamflow increased rivers, and ET₀ play as a dominant role for the streamflow decreased rivers in QLM. The impact of vegetation on streamflow variation illustrated the strong regional divergence with the contribution varied between -34.55% and 36.79%. The contribution of glacier and frozen ground degradation on streamflow variation were moderate with negative contributions of frozen ground degradation to the streamflow decrease varying between -31.09% and -0.43%, while the contribution of glacier mass balance to variation in streamflow varied between -2.42% and 11.63% in QLM. The results can utilize for understanding the impacts of climate change on alpine hydrological processes and provide the perspective of water resource management.