Meteorological and Hydrographic data

Introduction/Additional information: 

This message should not be transmitted when positional information or time of measurement are not available. If there is no data available for that particular data field, it should be displayed as "not available

Registrant: 
IMO Circ. 289
Message number: 
8
DAC: 
1
FI: 
31
State: 
in force
Used by: 
ARIADNA project
Number of slots (max): 
2
Permitted as from: 
01/06/2010
Details: 

Table 1.1 Metrological and Hydrographic data

Parameter No. of bits Description
Message ID 6 Identifier for Message 8; always 8.
Repeat Indicator 2 Used by the repeater to indicate how many times a message has been repeated. 0 - 3 0 = default 3 = do not repeat anymore
Source ID 30 MMSI number of source station.
Spare 2 Not used. Set to zero.
IAI 16 DAC = 001; FI = 31
Longitude 25 Longitude in 1/1,000 min, ±180 degrees as per 2's complement (East = positive, West = negative). 181 = not available = default
Latitude 24 Latitude in 1/1,000 min, ±90 degrees as per 2's complement (North = positive, South = negative). 91 = not available = default
Position Accuracy 1 1 = high (<10 m; Differential Mode of, e.g., DGNSS receiver) 0 = low (>10 m; Autonomous Mode of, e.g., GNSS receiver or of other electronic position fixing device) default = 0
Time Stamp UTC Day UTC Hour UTC Minute 5 5 6 UTC date and time of the data. 1 - 31 0 = not available = default 0 - 23 24 = not available = default 0 - 59 60 = not available = default
Average Wind Speed 7 Average of wind speed values for the last 10 minutes, in 1 knot steps. 0 - 125 knots 126 = wind 126 knots or greater 127 = not available = default
Wind Gust 7 Maximum wind speed reading during the last 10 minutes, in 1 knot steps. 0 - 125 knots 126 = wind 126 knots or greater 127 = not available = default
Wind Direction 9 Direction of the average wind during the last 10 minutes, in 1 degree steps. 0 - 359 degrees 360 = not available = default 361 - 511 (reserved for future use)
Wind Gust Direction 9 Direction of the maximum wind during the last 10 minutes, in 1 degree steps. 0 - 359 degrees 360 = not available = default 361 - 511 (not for use)
Air Temperature 11 Dry bulb temperature in degrees Celsius (as per 2's complement), in 0.1 degree steps. -60 to +60 degrees Celsius 601 - 1,023 (reserved for future use) -1,024 = data not available = default -1,023 to -601 (reserved for future use)
Relative Humidity 7 Relative Humidity, in 1% steps. 0 - 100% 101 = not available = default 102 -127 (reserved for future use)
Dew Point 10 Dew point temperature in degrees Celsius (as per 2's complement), in 0.1 degree steps. -20.0 to +50.0 degrees 501 = not available = default 502 - 511 (reserved for future use) -511 to -201 (reserved for future use)
Air Pressure 9 Air pressure, defined as pressure reduced to sea level, in 1 hPa steps. 0 = pressure 799 hPa or less 1 - 401 = 800 - 1200 hPa 402 = pressure 1201 hPa or greater 403 - 510 (reserved for future use) 511 = not available = default
Air Pressure Tendency 2 0 = steady 1 = decreasing 2 = increasing 3 = not available = default
Horizontal Visibility 8 Horizontal visibility, in 0.1 Nautical Miles steps (00000000 to 01111111). 0.0 - 12.6 Nautical Miles The most significant bit (MSB) indicates that the maximum range of the visibility equipment was reached and the reading shall be regarded as > x.x NM. (e.g., if 10110010, then visibility is 5.0 NM or greater) 127 = data not available = default
Water level (incl. tide) 12 Deviation from local chart datum, in 0.01 metre steps. -10.0 to +30.0 metres A value representing 0 - 4,000 is sent by the 12 binary bits. The water level is achieved by adding -10.0 to the sent value. Water level = (Integer value /100) – 10 for Integer = 0-4,000 4,001 = not available = default 4,002 – 4,095 (reserved for future use)
Water Level Trend 2 0 = steady 1 = decreasing 2 = increasing 3 = not available = default
Surface Current Speed (incl. tide) 8 Speed of Current measured at the sea surface, in 0.1 knot steps. 0.0 - 25.0 knots 251 = speed 25.1 knots or greater 255 = not available = default 252-254 (reserved for future use) 
Surface Current Direction 9 Direction of Current at the sea surface, in 1 degree steps. 0 - 359 degrees 360 = not available = default 361 - 511 (reserved for future use)
Current Speed, #2 8 Speed of Current 2 measured at a chosen level below the sea surface, in 0.1 knot steps. (Same as Surface Current Speed)
Current Direction, #2 9 Direction of Current 2, in 1 degree steps. (Same as Surface Current Direction)
Current Measuring level, #2 5 Measuring level below sea surface, in 1 metre increment. 0 - 30 metres 31 = not available = default
Current Speed, #3 8 Speed of Current 3 measured at a chosen level below the sea surface, in 0.1 knot steps. (Same as Surface Current Speed)
Current Direction, #3 9 Direction of Current 3, in 1 degree steps. (Same as Surface Current Direction)
Current Measuring level, #3 5 Measuring level below sea surface, in 1 metre steps. 0 - 30 metres 31 = data not available = default
Significant Wave Height 8 Height of the waves, in 0.1 metre steps. 0.0 - 25.0 metres 251 = height 25.1 metres or greater 255 = data not available = default 252 - 254 (reserved for future use)
Wave Period 6 Wave period, in 1 second steps. 0 - 60 seconds 61 - 62 (reserved for future use) 63 = not available = default
Wave Direction 9 Direction of waves, in 1 degree steps. 0 - 359 degrees 360 = data not available = default 361 - 511 (reserved for future use)
Swell Height 8 Height of the swell, in 0.1 metre steps. 0.0 - 25.0 metres 251 = height 25.1 metres or greater 255 = data not available = default 252 - 254 (reserved for future use)
Swell Period 6 Swell period, in 1 second steps. 0 - 60 seconds 61 - 62 (reserved for future use) 63 = not available = default
Swell Direction 9 Direction of swells, in 1 degree steps. 0 - 359 degrees 360 = not available = default 361 - 511 (reserved for future use)
Sea State 4 Beaufort Scale, as defined in Table 1.2
Water Temperature 10 Temperature of the water in degrees Celsius (as per 2's complement), in 0.1 degree steps. -10.0 to +50.0 degrees 501 = data not available = default 502 - 511 (reserved for future use) -511 to -101 (reserved for future use)
Precipitation (type) 3 According to WMO 306 Code table 4.201: 0 = reserved 1 = rain 2 = thunderstorm 3 = freezing rain 4 = mixed/ice 5 = snow 6 = reserved 7 = not available = default
Salinity 9 Salinity, in 0.1‰ (ppt) steps. 0.0 - 50.0 ‰ 50.1 = salinity 50.1 ‰ or greater 510 = not available = default 511 = sensor not available 502 - 509 (reserved for future use)
Ice 2 0 = No 1 = Yes 2 = (reserved for future use) 3 = not available = default
Spare 10 Not used. Set to zero
Total 360 Occupies 2 slots
 
Table 1.2 Beaufort scale
  Sea Conditions
0 Flat.
1 Ripples without crests.
2 Small wavelets. Crests of glassy appearance, not breaking.
3 Large wavelets. Crests begin to break; scattered whitecaps.
4 Small waves.
5 Moderate (1.2 m) longer waves. Some foam and spray.
6 Large waves with foam crests and some spray.
7 Sea heaps up and foam begins to streak.
8 Moderately high waves with breaking crests forming spindrift. Streaks of foam.
9 High waves (6-7 m) with dense foam. Wave crests start to roll over. Considerable spray.
10 Very high waves. The sea surface is white and there is considerable tumbling. Visibility is reduced.
11 Exceptionally high waves.
12 Huge waves. Air filled with foam and spray. Sea completely white with driving spray. Visibility greatly reduced.
13 not available = default
14 - 15 (reserved for future use)