Abstract:In order to explore the temporal and spatial evolution process of energy parameters dynamic response of sand covered loess slope in spring thawing period, two soil treatments (unfrozen slope and frozen slope) and four sand cover thicknesses (0, 1, 2 and 3 cm) were used under the same discharge (1 L/min). The temporal and spatial evolution process of runoff velocity (V), stream power (W), unit stream power (P), and runoff kinetic energy (E) under different soil treatments and different thickness of sediment cover were systematically analyzed. The results showed that: (1) The runoff velocity under different treatments decreased with the extension of runoff generation time, and increased with the increase of distance from the top of slope. The average runoff velocity of unfrozen slope and frozen slope varied from 0.23 to 0.35 m/s and from 0.18 to 0.35 m/s, respectively. The temporal and spatial variation of runoff depth was opposite to that of runoff velocity. The values of unfrozen slope and frozen slope varied from 0.36 to 1.32 mm and 0.46 to 2.89 mm, respectively. (2) The variation range of stream power of unfrozen slope and frozen slope was 0.22 ~ 0.82 and 0.29 ~ 1.13 N/(m·s), respectively. The average value of unit stream power of unfrozen slope and frozen slope varied from 0.047 to 0.072 m/s and 0.037 to 0.072 m/s, respectively. The runoff kinetic energy of unfrozen slope increased with the increase of sediment thickness, and the runoff kinetic energy of frozen slope increased at first and then decreased with the extension of time. In space, the energy parameters of unfrozen slope and frozen slope could be expressed by linear function (R2 > 0.71). (3) There was a significant linear relationship between runoff rate and runoff velocity and energy parameters (p <0.01). Runoff velocity and unit stream power could describe the runoff generation process of unfrozen slope and frozen slope under different sediment thickness. The results of this study can provide reference for the establishment of erosion model of sand covered loess slope in thawing period.