Abstract:
Background Erosion and sediment generation processes not only respond to climate and land use changes, but also further affect regional ecological environment and sustainable development, which is one of the most important land surface processes. The erosion and sediment generation in cold regions are affected by cryospheric processes such as glacier melting, snowmelt, and soil freeze-thaw. Under the influence of climate change, these processes and sediment flux change have great uncertainty. To analyze the mechanism and future changes of the erosion and sediment generation in cold regions, it is very important to improve the existing hydrological model to quantify the influence of cryospheric elements.
Methods We conducted a large number of literature reviews based on Web of Science and CNKI databases, summarized the influences of glacier melt, snowmelt and soil freeze-thaw on the erosion and sediment generation and related model algorithms, then compares the applicability of existing distributed hydrological models in cold regions.
Results 1) Glaciers mainly affect erosion and sediment generation through glacier runoff and glacier bedrock erosion. The calculation of glacier meltwater includes energy balance algorithm, temperature index algorithm and their improved versions, and then glacier runoff is calculated combining with different glacier dynamic algorithm and distribution methods of glacier meltwater in different hydrological models; the impact of bedrock erosion can be obtained by taking the glacier area as a whole to calculate the sediment flux and then coupling it with hydrological model. 2) The snowmelt process mainly affects erosion by increasing surface runoff. Snowmelt is also calculated by energy balance algorithm, temperature index algorithm or its improved versions and then usually treated as rainfall with zero kinetic energy to calculate erosion and sediment flux. 3) The impact of soil freeze-thaw includes freeze-thaw depth affecting runoff, freeze-thaw cycle increasing soil erodibility and freeze-thaw depth limiting the contributing erosion extent, which are mostly calculated by conceptual or empirical methods. 4) The existing hydrological models are relatively complete in calculating runoff under the influences of glacier melt, snowmelt, and soil freeze-thaw, but they do not adequately consider the effects of glacier melt and soil freeze-thaw on erosion and sediment generation.
Conclusions Based on the above summary, it is suggested that the existing model should add relevant algorithms to refine their model structure, then to enhance the applicability of existing models in cold regions. And in future studies, we can quantify the influence of cryosphere elements on erosion and sediment generation with the improved hydrological model, which will contribute to a better understanding of these processes and their future changes in cold regions.