10 0 MANUAL OBSERVATION
21 1 OPTICAL SCATTER SYSTEM COMBINED WITH PRECIPITATION OCCURRENCE SENSING SYSTEM
32 2 FORWARD AND/OR BACKSCATTER SYSTEM OF VISIBLE LIGHT
43 3 FORWARD AND/OR BACKSCATTER SYSTEM OF INFRARED LIGHT
54 4 INFRARED LIGHT EMITTING DIODE (IRED) SYSTEM
65 5 DOPPLER RADAR SYSTEM
714 14 OTHERS
815 15 MISSING VALUE
9