Geoscience Reference
In-Depth Information
Yasuda, N. (1975). The heat balance of the sea surface observed in the East China Sea.
Sci. Rept.
Tohoku Univ.,
Sendai, Japan.
Ser. 5, Geophys.
,
22
, 87-105.
Zilitinkevich, S. S. and Deardorff, J. W. (1974). Similarity theory for the planetary boundary layer of
time-dependent height.
J. Atmos. Sci.
,
31
, 1449-1452.
PROBLEMS
2.1
Multiple
choice.
Indicate
which
of
the
following
statements
are
correct.
An
unstable
atmosphere:
(a)
causes turbulence to be damped;
(b)
usually results in a vertical profile of the horizontal wind velocity that is more uniform than
that of a stable atmosphere;
(c)
causes the mean horizontal wind velocity to be larger (on a regional scale) than that of a
neutral atmosphere;
(d)
in the surface layer is favorable to disperse the pollutants;
(e)
is likely to be found over a deep lake in the spring, when warm air blows over the water;
2.2
Multiple choice. Indicate which of the following statements are correct. Stable conditions in the
atmosphere near the Earth's surface:
(a)
result in increased turbulent mixing (as compared to unstable conditions);
(b)
are necessarily the result of smoothness of the surface;
(c)
are often observed under nearly windless conditions with surface cooling by long-wave
radiation;
(d)
would be expected over an extensive and deep-water body in early spring under a cloudy
sky, when warm air moves over the water;
(e)
are more likely to be accompanied by dew (negative evaporation) than unstable conditions
(over land);
(f)
indicate that there is a high likelihood for thunderstorm activity.
2.3
For the ocean and for large lakes, typical values of the drag coefficient and the water vapor transfer
coefficient (both with wind and specific humidity measurements at 10 m above the surface) are of
the order of Cd
10
=
1
.
4
×
10
−
3
and Ce
10
=
1
.
2
×
10
−
3
, respectively. Calculate the roughness
parameters
z
0
and
z
0v
from these transfer coefficients for neutral conditions.
2.4
From observations at an ocean station, it has been determined that the estimation of the drag
coefficient, Cd
10
(with wind speed measurements, in m s
−
1
, at 10 m above the surface), can be
improved by assuming that it is a function of the wind speed, namely, Cd
10
=
×
10
−
3
. In contrast, the heat transfer coefficient, Ch
10
(with wind speed, in m s
−
1
, and temperature
both measured at 10 m), is a constant, namely Ch
10
=
1
.
2
×
10
−
3
. Determine the range of the
roughness parameters,
z
0
and
z
0h
,
in the wind speed range, 4
(0
.
80
+
0
.
05
u
10
)
≤
u
≤
21 m s
−
1
. Assume neutral
atmospheric conditions.
2.5
Solve
t
he previous problem but with a drag coefficient assumed to be given by Cd
10
=
0
.
50 (
u
10
)
0
.
45
×
10
−
3
, again, with the wind speed in m s
−
1
.
2.6
For wind speed measurements at
z
1
and
z
2
, and specific humidity measurements at
z
3
and
z
4
,
derive an expression for the water vapor transfer coefficient, Ce, in terms of
z
1
,
z
2
,
z
3
and
z
4
,
valid under neutral conditions. Make use of Equations (2.40) and (2.43).
