Geoscience Reference
In-Depth Information
Table 7.8 The list of environmental characteristics used for the detection of the beginning of a
tropical hurricane
Parameter
Identi
er
Parameter characteristic
Ocean surface temperature,
°
C
x
1
Temperature is measured on the depths 1.0
or 1.5 m depending on the buoy station
type with precision
±
0.003 to
±
0.02
°
C
Wind speed (m/s) and its direction (in
degrees on clockwise from northern
direction)
x
2
, x
3
Wind parameters are measured on the
altitude 3.5 m. Wind speed is measured
with precision 3 %. In direction it is
determined with precision 5.0
-
7.8
°
Precipitation (mm/h)
x
4
Precipitation are registered every 10 min
on the altitude 3.5 m with preci-
sion
±
0.4 mm/h.
Sea water density (kg m
3
)
x
5
Water density is calculated as function of
its salinity
Depth of the isotherm 20
°
C
x
6
Depth of isotherm is calculated on the base
of vertical temperature distribution by
means of linear interpolation with the step
20 m by depth
Water temperature of
xed depths
{h
i
},
°
C
x
7
(h
i
)
Water temperature is measured up to
750 m on the
fixed horizons with the
precision
±
0.02
°
C
Relative humidity of atmospheric air,
%
x
8
Air humidity is measured on the altitude
2.2 m above the sea level with
precision
±
2.7 %
Atmospheric pressure, atm.
x
9
Atmospheric pressure is fixed with the
precision
0.01 % on the altitude 3 m
above the sea level
±
Atmospheric temperature,
°
C
x
10
Atmospheric temperature is measured on
the latitude 2.2 m with the
precision
±
0.2
°
C
Sea water salinity,
‰
x
11
Salinity is assessed by the data on the
water temperature and its conductivity
with the precision
±
0.02
‰
Signi
cant wave height, m
x
12
It is calculated as the average of the
highest one-third of all of the wave heights
during the 20-min sampling period
Dominant wave period, s
x
13
It is the period with the maximum wave
energy
Average wave period, s
x
14
It is the period (seconds) of all waves
during the 20-min period
The direction from which the waves at
the dominant period are coming,
degrees
x
15
The units are degrees from true North,
increasing clockwise, with North as 0
(zero) degrees and East as 90
°
C x
16
Dewpoint temperature taken at the same
height as the air temperature measurement
Station visibility, nmi x
17
Buoy stations are limited to reports from 0
to 1.6 nmi
Meteorological parameters are measured by of the TAO/TRITON&PIRATA system
Dewpoint temperature,
°
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