Many drifting buoys are deployed from ships and
aircraft into the Gulf of Mexico and into the Atlantic and
Pacific Oceans. Drifting buoys move with the
prevailing currents and automatically report observed
meteorological and oceanographic elements via
satellite. There are several types of drifting buoys, and
not all buoys transmit the same package of
environmental data. Normally, drifting buoys sample
data continuously, but data is reported only when polar-
orbiting meteorological satellites pass over the buoy
positions. This occurs a minimum of twice a day.
Information observed by drifting buoys is encoded
in WMO International Code FM 18-XI BUOY. This
code contains some elements similar to the ship
S y n o p t i c c o d e a n d o t h e r s s i m i l a r t o t h e
Bathythermograph code. The symbolic format of the
BUOY code is shown in table 2-3. The report contains 5
sections of data, identified as section 0 through section
4. Section 0 is identification information, and section 1
contains meteorological and other non-marine data.
Section 2 contains surface marine data. Section 3 is
used to report bathymetric readings, while the last
section, section 4, is used to report engineering and
quality control data.
SECTION 0 ZZYY A1bwnbnbnb YYMMJ GGggiw
QcLaLaLaLaLa LoLoLoLoLoLo (6Q1QtQA/)
SECTION 1 111QdQx 0ddff 1snTTT 2SnTdTdTd or (29UUU)
3POPOPOPO 4PPPP 5appp
SECTION 2 222QdQx 0SnTwTwTw 1PwaPwaHwaHwa 20PwaPwaPwa
21HwaHwaHwa
SECTION 3333Qd1Qd2 8887k2 2ZnZnZnZn 3TnTnTnTn 4SnSnSnSn
(66k69k3 2ZnZnZnZn dndncncncn)
SECTION 4 444 1QPQ2QTWQ4 2QNQLQA/ QcLaLaLaLaLa
LoLoLoLoLoLo
or (YYMMJ GGgg/ 7VBVBdBdB) 8ViViViVi
9idZdZdZd
Data from drifting buoys is relayed from satellites
to designated sites around the world, where the
information is checked for validity and then transmitted
over environmental networks. In most cases, the data is
already received from the buoy in the ZZYY format,
and only the data quality indicators must be encoded.
A typical drifting buoy report, which reports
weather and ocean temperatures every 10 meters to 150
meters, would appear similar to the following:
SSVX06 KARS 231145
ZZYY 93503 23027 11454 712238 095139 11119
00308 10255 29075 30132 40133 52003 22219
00262 10302 33311 88870 20010 31820 20020
31252 20030 31103 20040 31055 20050 31037
20060 31027 20070 31002 20080 31002 20090
30944 20100 30915 20110 30891 20120 30830
20130 30876 20140 30844 20150 30819 66091
20150 18135 444 201// 23027 1000/ 71227
81101
90150;
Other than the information in the buoy
identification section, all other data is optional; it is
reported only when available. Many drifting buoys
Table 2-3.—Symbolic Format of WMO Code FM 18-XI
BUOY
report surface conditions until the battery fails (about 6
to 12 months), but only report subsurface
temperatures/currents/depths for the first 3 to 6 months
after deployment, the engineering life of the "tails."
IDENTIFICATION SECTION
All code groups in section 0 must be included in
each report with the exception of the last group. All
buoy reports, even those grouped within a collective
bulletin, begin with the data type identifier "ZZYY."
Group A1bwnbnbnb is the WMO assigned area,
block, and identification number of each individual
buoy. The number is assigned before the buoy is
deployed, based on the intended deployment location.
This number will remain the same throughout the life of
the buoy. In our example, the buoy identifier is 93503.
Groups YYMMJ (the day, month, and year) and
GGggiw are nearly identical to the bathy code
identification groups. except for the indicator iw used as
the last digit of the group. This code figure is used to
indicate the units of wind speed (1 = meters per second,
4 = knots). In our example, the date and time of the
observation are provided by 23027 11454, for the 23d of
February, 1997, at 11452. The indicator 4 shows the
wind is measured in knots.
The buoy’s position is given by the groups
QcLaLaLaLaLa LOLOLOLOLOLO. Notice that these are
each 6-digit groups instead of the standard 5-digit
groups. As in the bathy code, Qc is quadrant of the globe
from WMO code table 3333 (refer to Appendix III).
However, LaLaLaLaLa is the latitude to the nearest
thousandth of a degree (3 decimal places). Likewise,
LoLoLoLoLoLo is the longitude to the nearest
thousandth of a degree. A report may replace the last
figure in each group with a slant if the position is only
reported to the nearest hundredth of a degree. For
example, 712238 095139 would report a position in
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