*2.1. Observation Station and Disdrometer Datasets*

Microphysical characteristics of different precipitation types were measured at Yulin Ecohydrological Station (109◦28 2.7E, 38◦26 43.6N, 1236 m above sea level (a.s.l.), located in Mu Us Sandy Land) in Shaanxi Province, China. Mu Us Sandy Land has a semi-arid climate type with a low amount of precipitation [24]. The average annual precipitation in this area is 413 mm (from the year 1951 to 2018, measured by Yulin Meteorological Station (109◦28 12E, 38◦9 36N, 936 m a.s.l.)).

Figure 1a shows the location of Yulin Ecohydrological Station and Yulin Meteorological Station. One OTT Parsivel-2 Disdrometer was placed in Yulin Ecohydrological Station, and continuously recorded data during a 1-year period between 10 August 2018 and 10 August 2019. There are also four TE525MM rainfall gauges placed at the same location (shown in Figure 1b), and the specific placement of the disdrometer and the four gauges is proposed by Xie et al. [25], providing a reference for the measurement data by the disdrometer. Data were recorded every 30 min during the researching period, with the four gauges recording data simultaneously and individually. The disdrometer conducted a 54 cm<sup>2</sup> laser beam to record the rainfall spectrum every 1 min. The record of the disdrometer includes two parts: raindrop diameters (*D*) and raindrop terminal velocity (*v*). When precipitation particles pass the laser beam of the sensor, the beam is blocked off by the particles equal to the diameters, and the output voltage will be reduced. If there is no particle passing through, the voltage will then be recorded as maximum. The duration of the reducing signal will be used to determine the terminal speed of a particle. Through the observation by the disdrometer, radar reflectivity (*Z*), rainfall intensity (*R*) and kinetic energy (KE) are derived from *D* and *v*. Figure 2 summarizes how the materials and methods and results are managed via a schematic.
