You can use them to provide context information for a measured value.
Every entry is listed together with its measure unit, length in characters or digits and description.
Code Description Unit Format 001001 WMO BLOCK NUMBER Numeric 2 digits 001002 WMO STATION NUMBER Numeric 3 digits 001007 SATELLITE IDENTIFIER CODE TABLE 1007 3 chars 001008 AIRCRAFT REGISTRATION NUMBER OR OTHER IDENTIFICATION Character 8 chars 001011 SHIP OR MOBILE LAND STATION IDENTIFIER Character 9 chars 001012 DIRECTION OF MOTION OF MOVING OBSERVING PLATFORM** DEGREE TRUE 3 digits 001013 SPEED OF MOTION OF MOVING OBSERVING PLATFORM* M/S 3 digits 001019 LONG STATION OR SITE NAME Character 32 chars 001063 ICAO LOCATION INDICATOR Character 8 chars 001192 [SIM] MeteoDB station ID Numeric 8 digits 001193 [SIM] Report code Numeric 5 digits 001212 AIR QUALITY OBSERVING STATION LOCAL CODE Character 7 chars 001213 AIRBASE AIR QUALITY OBSERVING STATION CODE Character 7 chars 001214 GEMS AIR QUALITY OBSERVING STATION CODE Character 6 chars 001215 AIR QUALITY OBSERVING STATION DOMINANT EMISSION SOURCE CODE TABLE 001215 1 chars 001216 AIR QUALITY OBSERVING STATION AREA TYPE CODE TABLE 001216 1 chars 001217 AIR QUALITY OBSERVING STATION TERRAIN TYPE CODE TABLE 001217 2 chars 002001 TYPE OF STATION CODE TABLE 2001 1 chars 002002 TYPE OF INSTRUMENTATION FOR WIND MEASUREMENT FLAG TABLE 2002 2 digits 002005 PRECISION OF TEMPERATURE OBSERVATION K #.## 002011 RADIOSONDE TYPE CODE TABLE 2011 3 chars 002012 RADIOSONDE COMPUTATIONAL METHOD CODE TABLE 2012 2 chars 002048 SATELLITE SENSOR INDICATOR CODE TABLE 2048 2 chars 002061 AIRCRAFT NAVIGATIONAL SYSTEM CODE TABLE 2061 1 chars 002062 TYPE OF AIRCRAFT DATA RELAY SYSTEM CODE TABLE 2062 2 chars 002063 AIRCRAFT ROLL ANGLE DEGREE ###.## 002070 ORIGINAL SPECIFICATION OF LATITUDE/LONGITUDE CODE TABLE 2070 2 chars 004001 YEAR YEAR 4 digits 004002 MONTH MONTH 2 digits 004003 DAY DAY 2 digits 004004 HOUR HOUR 2 digits 004005 MINUTE MINUTE 2 digits 004006 SECOND SECOND 2 digits 004192 [SIM] Time range type Numeric 4 digits 004193 [SIM] Time range P1 Numeric 10 digits 004194 [SIM] Time range P2 Numeric 10 digits 005001 LATITUDE (HIGH ACCURACY) DEGREE ##.##### 005021 BEARING OR AZIMUTH DEGREE TRUE ###.## 005022 SOLAR AZIMUTH DEGREE TRUE ###.## 005040 ORBIT NUMBER Numeric 8 digits 005041 SCAN LINE NUMBER Numeric 3 digits 005043 FIELD OF VIEW NUMBER Numeric 3 digits 006001 LONGITUDE (HIGH ACCURACY) DEGREE ###.##### 007001 HEIGHT OF STATION (SEE NOTE 1) M 5 digits 007002 HEIGHT OR ALTITUDE M #####0 007004 PRESSURE PA #####0 007024 SATELLITE ZENITH ANGLE DEGREE ###.## 007025 SOLAR ZENITH ANGLE DEGREE ###.## 007031 HEIGHT OF BAROMETER ABOVE MEAN SEA LEVEL (SEE NOTE 4) M ####.# 007192 [SIM] First level type Numeric 4 digits 007193 [SIM] Level L1 Numeric 10 digits 007194 [SIM] Level L2 Numeric 10 digits 007195 [SIM] Second level type Numeric 4 digits 008001 VERTICAL SOUNDING SIGNIFICANCE FLAG TABLE 8001 3 digits 008004 PHASE OF AIRCRAFT FLIGHT CODE TABLE 8004 1 chars 008021 TIME SIGNIFICANCE CODE TABLE 8021 2 chars 008044 (VAL) CAS REGISTRY NUMBER Character 11 chars 010003 GEOPOTENTIAL M**2/S**2 7 digits 010004 PRESSURE PA #####0 Code Description Unit Format 010009 GEOPOTENTIAL HEIGHT GPM 5 digits 010051 PRESSURE REDUCED TO MEAN SEA LEVEL PA #####0 010052 ALTIMETER SETTING (QNH) PA #####0 010061 3-HOUR PRESSURE CHANGE PA ####0 010063 CHARACTERISTIC OF PRESSURE TENDENCY CODE TABLE 10063 2 chars 010197 ANEMOMETER HEIGHT M 3 digits 011001 WIND DIRECTION DEGREE TRUE 3 digits 011002 WIND SPEED M/S ###.# 011003 U-COMPONENT M/S ###.# 011004 V-COMPONENT M/S ###.# 011016 EXTREME COUNTERCLOCKWISE WIND DIRECTION OF A VARIABLE WIND DEGREE TRUE 3 digits 011017 EXTREME CLOCKWISE WIND DIRECTION OF A VARIABLE WIND DEGREE TRUE 3 digits 011041 MAXIMUM WIND GUST SPEED M/S ###.# 012001 TEMPERATURE/DRY-BULB TEMPERATURE K ###.# 012002 WET-BULB TEMPERATURE K ###.# 012003 DEW-POINT TEMPERATURE K ###.# 012011 MAXIMUM TEMPERATURE K ###.# 012012 MINIMUM TEMPERATURE K ###.# 012030 SOIL TEMPERATURE K ###.# 012061 SKIN TEMPERATURE K ###.# 012063 BRIGHTNESS TEMPERATURE K ###.# 013001 SPECIFIC HUMIDITY KG/KG .##### 013003 RELATIVE HUMIDITY % 3 digits 013011 TOTAL PRECIPITATION / TOTAL WATER EQUIVALENT KG/M**2 ####.# 013013 TOTAL SNOW DEPTH M ###.### 014016 NET RADIATION J/M**2 #####0000 014018 INSTANTANEOUS SHORT-WAVE RADIATION W/M**2 ####000 014021 GLOBAL SOLAR RADIATION, INTEGRATED OVER PERIOD SPECIFIED J/M**2 #####0000 015192 [SIM] NO Concentration KG/M**3 .############# 015193 [SIM] NO2 Concentration KG/M**3 .############# 015194 [SIM] O3 Concentration KG/M**3 .############# 015195 [SIM] PM10 Concentration KG/M**3 .############# 020001 HORIZONTAL VISIBILITY M ####0 020003 PRESENT WEATHER (SEE NOTE 1) CODE TABLE 20003 3 chars 020004 PAST WEATHER (1) (SEE NOTE 2) CODE TABLE 20004 2 chars 020005 PAST WEATHER (2) (SEE NOTE 2) CODE TABLE 20005 2 chars 020009 GENERAL WEATHER INDICATOR (TAF/METAR) CODE TABLE 20009 2 chars 020010 CLOUD COVER (TOTAL) % 3 digits 020011 CLOUD AMOUNT CODE TABLE 20011 2 chars 020012 CLOUD TYPE CODE TABLE 20012 2 chars 020013 HEIGHT OF BASE OF CLOUD M 5 digits 020019 SIGNIFICANT PRESENT OR FORECAST WEATHER Character 9 chars 020021 TYPE OF PRECIPITATION FLAG TABLE 20021 10 digits 020062 STATE OF THE GROUND (WITH OR WITHOUT SNOW) CODE TABLE 20062 2 chars 020193 [SIM] Cloud type (METAR) Character 2 chars 022001 DIRECTION OF WAVES DEGREE TRUE 3 digits 022011 PERIOD OF WAVES S 2 digits 022012 PERIOD OF WIND WAVES S 2 digits 022021 HEIGHT OF WAVES M ###.# 022022 HEIGHT OF WIND WAVES M ###.# 022042 SEA/WATER TEMPERATURE K ###.# 022070 SIGNIFICANT WAVE HEIGHT M ##.## 022071 SPECTRAL PEAK WAVE PERIOD S ##.# 022074 AVERAGE WAVE PERIOD S ##.# 025076 LOG-10 OF (TEMP-RAD CENTRAL WAVENUMBER) FOR ATOVS LOGM-1 ##.######## 031000 SHORT DELAYED DESCRIPTOR REPLICATION FACTOR Numeric 1 digits 031001 DELAYED DESCRIPTOR REPLICATION FACTOR Numeric 3 digits 031002 EXTENDED DELAYED DESCRIPTOR REPLICATION FACTOR Numeric 5 digits 031011 DELAYED DESCRIPTOR AND DATA REPETITION FACTOR Numeric 3 digits Code Description Unit Format 031012 EXTENDED DELAYED DESCRIPTOR AND DATA REPETITION FACTOR Numeric 5 digits 031021 ASSOCIATED FIELD SIGNIFICANCE CODE TABLE 31021 2 chars 031031 DATA PRESENT INDICATOR FLAG TABLE 31031 1 digits 033002 QUALITY INFORMATION CODE TABLE 33002 1 chars 033003 QUALITY INFORMATION CODE TABLE 33003 1 chars 033005 QUALITY INFORMATION (AWS DATA) FLAG TABLE 33005 10 digits 033006 INTERNAL MEASUREMENT STATUS INFORMATION (AWS) CODE TABLE 33006 1 chars 033007 PER CENT CONFIDENCE % 3 digits 033015 DATA QUALITY CHECK INDICATOR CODE TABLE 33015 2 chars 033020 QUALITY CONTROL INDICATION OF FOLLOWING VALUE CODE TABLE 33020 1 chars 033021 QUALITY OF FOLLOWING VALUE CODE TABLE 33021 1 chars 033022 QUALITY OF BUOY SATELLITE TRANSMISSION CODE TABLE 33022 1 chars 033023 QUALITY OF BUOY LOCATION CODE TABLE 33023 1 chars 033024 STATION ELEVATION QUALITY MARK (FOR MOBILE STATIONS) CODE TABLE 33024 2 chars 033025 ACARS INTERPOLATED VALUES CODE TABLE 33025 1 chars 033026 MOISTURE QUALITY CODE TABLE 33026 2 chars 033027 LOCATION QUALITY CLASS (RANGE OF RADIUS OF 66 % CONFIDENCE) CODE TABLE 33027 1 chars 033030 SCAN LINE STATUS FLAGS FOR ATOVS FLAG TABLE 33030 8 digits 033031 SCAN LINE QUALITY FLAGS FOR ATOVS FLAG TABLE 33031 8 digits 033032 CHANNEL QUALITY FLAGS FOR ATOVS FLAG TABLE 33032 8 digits 033033 FIELD OF VIEW QUALITY FLAGS FOR ATOVS FLAG TABLE 33033 8 digits 033035 MANUAL/AUTOMATIC QUALITY CONTROL CODE TABLE 33035 2 chars 033036 NOMINAL CONFIDENCE THRESHOLD % 3 digits 033037 WIND CORRELATION ERROR FLAG TABLE 33037 7 digits 033038 QUALITY FLAGS FOR GROUND-BASED GNSS DATA FLAG TABLE 33038 4 digits 033040 CONFIDENCE INTERVAL PERCENT 3 digits 033041 ATTRIBUTE OF FOLLOWING VALUE CODE TABLE 33041 1 chars 033050 GLOBAL GTSPP QUALITY FLAG CODE TABLE 33050 2 chars 033192 [SIM] Climatological and consistency check PERCENT 3 digits 033193 [SIM] Time consistency PERCENT 3 digits 033194 [SIM] Space consistency PERCENT 3 digits 033195 [SIM] MeteoDB variable ID Numeric 8 digits 033196 [SIM] Data has been invalidated CODE TABLE 33196 1 chars 033197 [SIM] Manual replacement in substitution CODE TABLE 33197 1 chars