0 0 MANUAL OBSERVATION
1 1 OPTICAL SCATTER SYSTEM COMBINED WITH PRECIPITATION OCCURRENCE SENSING SYSTEM
2 2 FORWARD AND/OR BACK-SCATTER SYSTEM OF VISIBLE LIGHT
3 3 FORWARD AND/OR BACK-SCATTER SYSTEM OF INFRARED LIGHT
4 4 INFRARED LIGHT EMITTING DIODE (IRED) SYSTEM
5 5 DOPPLER RADAR SYSTEM
14 14 OTHER
15 15 MISSING VALUE
