Geoscience Reference
In-Depth Information
Table A3.1
Synoptic code (World Meteorological Organization, January 1982).
Symbol Key
Example
Comments
{
yy
Day of the month (GMT)
05
All groups are in blocks
GG
Time (GMT) to nearest hour
06
of five digits
i
w
Indicator for type of wind speed observation and units
4
Measured by anemometer
(knots)
IIiii
International index number of station
i
R
Indicator: precipitation data included/omitted (code)
3
Data omitted
i
X
Indicator: station type + ww W
1
W
2
included/omitted (code)
1
Manned station with ww W
1
W
2
included
h
Height of lowest cloud (code)
3
vv
Visibility (code)
66
N
Total cloud amount (oktas)
7
dd
Wind direction (tens of degrees)
32
ff
Wind speed (knots, or m s
-1
)
20
Knots
I
Header
1
S
n
Sign of temperature (code)
0
Positive value
TTT
Temperature (0.1°C), plotted rounded to nearest 1°C
203
(1 = negative value)
2
Header
2
S
n
Sign of temperature (code)
0
T
d
T
d
T
d
Dew-point temperature (as TTT)
138
4
Header
4
PPPP
Mean sea-level pressure (tenths of mb, omitting thousands)
0105
5
Header
5
a
Characteristic of pressure tendency (coded symbol)
3
ppp
Three-hour pressure tendency (tenths of mb)
005
7
Header
7
ww
Present weather (coded symbol)
80
}
W
1
Past weather (coded symbol)
9
(W
1
must be greater
W
2
Past weather (coded symbol)
8
than W
2
)
8
Header
8
N
h
Amount of low cloud (oktas)
4
C
L
Low cloud type (coded symbol)
2
C
M
Medium cloud type (coded symbol)
5
C
H
High cloud type (coded symbol)
2
Note
: Group 3 is for a report of surface pressure and group 6 for precipitation data.
