Assessment of soil erosion characteristics in response to temperature and precipitation in a freeze-thaw watershed

Precipitation and temperature are important factors affecting soil erosion especially in mid-high latitude areas. The effects of climatic factors on soil erosion have been observed in many studies. However, watershed soil erosion and its links between the contributors under climatic impacts display unique characteristics due to the freeze-thaw process, which are not fully understood. Therefore, the approaches of meteorological data monitoring, hydrological modelling (Soil and Water Assessment Tool) and multivariate statistical analysis of long-term data were integrated. Based on the cluster analysis, four categories of years (C1-C4) were classified as high precipitation, freezing with sufficient precipitation, dry hot, and normal years, respectively. The soil erosion loads from C1 to C4 were 2.03 t ha−1 a−1, 1.27 t ha−1 a−1, 2.12 t ha−1 a−1, and 1.61 t ha−1 a−1, respectively. The results demonstrated that soil erosion tended to increase in years observed with high precipitation and in years observed with cold temperature but sufficient precipitation, with the erosion loads under these two categories respectively 26% and 32% higher than the load in normal years. Low temperature combined with adequate precipitation may cause higher soil loss in the freeze-thaw areas. Furthermore, runoff and precipitation were the dominate factors affecting soil erosion, with high correlations with erosion load (0.920, p = 0.01 and 0.768, p = 0.01, respectively). Nonetheless, snowmelt runoff and Rs played more substantial roles than precipitation in the snowmelt period. Temperature was also related to soil erosion, but not for the snowmelt period. The weakest relationships between erosion and dominate contributors were observed in C1 under all conditions, but the strongest relationships were found in C4 except that between Rs in the snowmelt period. These findings of the study provide important implications for soil erosion control in freeze-thaw areas, which can help decision makers conserve soil and water resources with high efficiency in the event of adverse weather conditions.