Marine Ecosystems Research Department - jamstec japan agency ...

Japan Marine Science and Technology Center
Frontier Research System for Global Change
1000
800
a
V base = 0.24 ms -1
V base = 0.12 ms -1
V base = 0.06 ms -1
10000
8000
b V base = 2.0 ms -1
V base = 1.0 ms -1
V base = 0.5 ms -1
Nd (cm -3 )
600
400
Nd (cm -3 )
6000
4000
200
2000
0
0 200 400 600 800 1000
0
0 2000 4000 6000 8000 10000
N c (0.2%) (cm -3 )
N c (0.5%) (cm -3 )
Fig. 7 a. Relationship between cloud droplet concentration at 100m above cloud base, N d , and
the cumulative number of CCN that can be activated at 0.2% supersaturation, N c (0.2%),
for three updraft velocities: 0.24, 0.12 and 0.06m s -1 .
b. Relationship between the cloud droplet concentration at 100m above cloud base, N d ,
and the cumulative number of CCN that can be activated at 0.5% supersaturation, N c
(0.5%), for three updraft velocities: 0.5, 1.0, and 2.0m s -1 .
c-. Improvement of Cloud-resolving Models and
Numerical Experiments
A mesoscale-convection-resolving model (MCRM),
which had been developed and applied to cloud clusters
associated with a Baiu front in the previous year, was
used to simulate and understand typhoon Flo (T). It
was shown that the MCRM could simulate rainfall distributions
and other features of the typhoon much better
than those obtained in an international model intercomparison
(Nagata et al., ) by other researchers and
operational prediction centers (Figure ). Although it is
desirable to improve the MCRM further in coming years,
it appears that the performance of the model has nearly
attained a reasonable level with respect to parameterization
(or implicit representation) of the effects of cumulus
convection which is of the subgrid-scale in a model having
horizontal grid sizes of ~km. On the other hand, a
nonhydrostatic model, which can resolve cumulus convection
with a grid size of km, was significantly
improved, and used to simulate and understand a tropical
squall-line. A triply-nested grid version was also developed
to study efficiently weather systems such as Baiu
fronts and tropical cyclones in the near future, which
should also be a basis for improvement of the MCRM.
c-. Understanding the Physical Processes of
Mesoscale Convective Systems
Numerical experiments of the mesoscale system
along the Meiyu front were performed. The system is
the one observed near Fuyang radar site (. E,
. N) on July , . Two datasets, i.e., the
LATITUDE
LATITUDE
QC (200) at 24 hours
QC (200) at 48 hours
25
25
4
4
3
3
20
2 20
2
1
1
0
0
0
0
15
15
130 135 140 145
130 135 140 145
LONGITUDE
LONGITUDE
Fig. 8 Cloud water content at 200 hPa (upper panels) and lowlevel
rainwater content (lower panels) in Typhoon 9019
(Flo) simulated by our model (MCRM) at 24 hours (left) and
48 hours (right) after the initial time.
LATITUDE
LATITUDE
QR (SFC) at 24 hours
QR (SFC) at 48 hours
25
25
4
4
2
2
20
20
0
0
0
0
0
0
15
15
130 135 140 145
130 135 140 145
LONGITUDE
LONGITUDE
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