Decreased inter-annual streamflow variability are found in snow-affected catchments by using the second-order Budyko framework

With persistent global warming, more precipitation will land on the earth's surface as rainfall instead of snowfall. Here, based on observations from hundreds of catchments, we proposed a framework (the second-order Budyko framework) to investigate hydro-climatic relationships between annual streamflow and snowfall fraction. Results show that in addition to the mean annual streamflow, the inter-annual streamflow variability will also decrease with lower snowfall fraction in the context of warming. The positive relationship between streamflow variability and snowfall fraction may result from the asymmetric hydrological effects of snowfall in the wet and dry years. To our knowledge, it is the first attempt to detect the role of snowfall on the streamflow variability. This study provides new way and understandings of the second-order hydro-climatic effects, and these findings will facilitate decisions for water resource management in a changing climate.