THE NEAR-SURFACE LAYER OF THE OCEAN
where 0 8
n
m
-3 m
-1 and
0.21
3
6
4.1 10 3.6 10 P
/
u
u
(in m
-1 ) are
parameters describing the distribution, P is the rain rate (in m s
-1 ), and N is
the particle density (in m
-3 ).
Natural rain can exhibit more complicated drop size distributions
(Ulbrich, 1983). In particular, (1.65) does not capture “instantaneous”
raindrop size distributions. Remote sensing of reflectivity and attenuation
with the dual-wavelength radar technique, or the reflectivities at horizontal
and vertical polarization with the polarimetric radar, opens new
opportunities in the measurement of rain parameters (Zhang et al., 2003). At
this point the use of the Marshall-Palmer dependence is “justified” only by
the fact that the rainrate has nearly always been the only rain parameter
measured.
From (1.64) and (1.65), the total volume of rainwater is
3
0
0
0
0
0
0
4
0
4
exp 2
3
2
u
u
n
V V
n r
r dr V
S
S
f
/
/
³
.
(1.66)
Surface tension prevents drops with smaller than critical radius c
r from
entering the water body, since they do not have sufficient energy to
overcome the surface tension. These drops stay on the sea surface and lead
to a surface flux rather than a volume flux. The critical radius below which
raindrops do not penetrate the ocean surface has been observed to be c
r = 0.4
mm by Oguz and Prosperetti (1991) and about c
r = 0.75 mm by Green and
Houk (1979). The latter result was obtained in a laboratory experiment at
rather low impact velocities, however.
The volume of freshwater that does not submerge but stays at the surface
is determined as follows:
4
3
3
0 0
0
0
0
0
0
0
0
0
4
8
exp 2
exp 2
3
3
c
c
r
r
s
u
V V
n r
r dr V
r
r dr
S
/
/
/
³
³
.
(1.67)
et al. (1997) obtained the following solution to (1.67):
2 2
3 3
0
4
8
1 1 2
exp 2
2
6
c
c
s
c
c
r
r
V V
r
r
ª
º
§
·
/
/
/
/
«
»
¨
¸
«
»
©
¹
¬
¼
.
(1.68)
The volume of freshwater due to rain submerging into the ocean is:
36
6
10
u
Schl ssel
ü
where 0 8
n
m
-3 m
-1 and
0.21
3
6
4.1 10 3.6 10 P
/
u
u
(in m
-1 ) are
parameters describing the distribution, P is the rain rate (in m s
-1 ), and N is
the particle density (in m
-3 ).
Natural rain can exhibit more complicated drop size distributions
(Ulbrich, 1983). In particular, (1.65) does not capture “instantaneous”
raindrop size distributions. Remote sensing of reflectivity and attenuation
with the dual-wavelength radar technique, or the reflectivities at horizontal
and vertical polarization with the polarimetric radar, opens new
opportunities in the measurement of rain parameters (Zhang et al., 2003). At
this point the use of the Marshall-Palmer dependence is “justified” only by
the fact that the rainrate has nearly always been the only rain parameter
measured.
From (1.64) and (1.65), the total volume of rainwater is
3
0
0
0
0
0
0
4
0
4
exp 2
3
2
u
u
n
V V
n r
r dr V
S
S
f
/
/
³
.
(1.66)
Surface tension prevents drops with smaller than critical radius c
r from
entering the water body, since they do not have sufficient energy to
overcome the surface tension. These drops stay on the sea surface and lead
to a surface flux rather than a volume flux. The critical radius below which
raindrops do not penetrate the ocean surface has been observed to be c
r = 0.4
mm by Oguz and Prosperetti (1991) and about c
r = 0.75 mm by Green and
Houk (1979). The latter result was obtained in a laboratory experiment at
rather low impact velocities, however.
The volume of freshwater that does not submerge but stays at the surface
is determined as follows:
4
3
3
0 0
0
0
0
0
0
0
0
0
4
8
exp 2
exp 2
3
3
c
c
r
r
s
u
V V
n r
r dr V
r
r dr
S
/
/
/
³
³
.
(1.67)
et al. (1997) obtained the following solution to (1.67):
2 2
3 3
0
4
8
1 1 2
exp 2
2
6
c
c
s
c
c
r
r
V V
r
r
ª
º
§
·
/
/
/
/
«
»
¨
¸
«
»
©
¹
¬
¼
.
(1.68)
The volume of freshwater due to rain submerging into the ocean is:
36
6
10
u
Schl ssel
ü