Measured fall velocities of raindrops allow for a precise normalization from the number of drops reaching the measuring area to the volume above. Melting Particles Figures 8 and 9 present melting snow. The bigger particles are still of mixed phase, they have not the terminal fall velocity of raindrops and they show quite irregular shapes. Figure 9 gives an example. Snowflakes Figures 10 and 11 show data acquired during snowfall.
Snowflakes have all sorts of irregular shadows.
It should be noted that only the shadow of snowflakes is recorded, not their detailed three-dimensional structure. The discussion on reliability of such methods needs the verification with point monitoring ground based gages. In widespread rain situations with moderate rainrates tipping bucket raingages promise to be reliable. Figure 12 presents a rainrate versus time diagram. The two devices have been installed in a distance of 21 meters.