Low (web) Quality - BALTEX

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summer particularly in the Pacific side, indicating that not
only synoptic scale behavior but also finer scale feature may
take an important role by, such as, localized disturbances.
The wind fields are similarly reproduced as air temperature
(figure not shown).
In contrast, precipitation is not reproduced as well as
temperature and wind by the JP10, with averaged correlation
coefficient of 0.3~0.7. Figure 4 shows the same but for
precipitation, with significantly larger number of the
observatories. Interestingly, the seasonality of the scores is
more apparent in precipitation, i.e., summer and Pacific side
precipitation is more difficult, due to sub-grid scale
convective activity and also low quantitative reproducibility
of typhoon and Baiu systems by the model and analysis.
Hazardous snow events
In Figure 5, monthly mean snow water equivalent (SWE)
amount is averaged over all Honshu Island. According to the
hazard record in Japan reported by JMA, there were deadly
severe events in the winters of 1960-61, 62-63, 73-74, 76-77,
80-81, 83-86, and 2005-06. These hazardous events are
captured in this preliminary analysis of JP10 to some extent.
Note that there is no official record before 1960.
Figure 4. Distributions of correlation coefficients of
monthly-long daily precipitation in four seasons.
Number of the observation sites and arithmetic
average of the coefficients of all sites are also shown.
Precipitation
Precip [mm/day]
16
14
12
10
8
6
4
2
0
Annual
Feb
Apr
Jun
Aug
16
14
12
10
8
6
4
Kyushu 2
Kant o 0
DecAll
Surface Air Temperature
Oct
Annual
Feb
Apr
Jun
Aug
Oct
Kyushu
Kant o
DecAll
All
N- Hokkaido
S- Hokkaido
Tohoku
Kant o
Chubu
Kinki
Shikoku
Kyushu
Okinawa
Temperature [C]
30
25
20
15
10
5
0
-5
-10
Annual
Feb
Apr
Jun
Aug
Oct
AMeDAS
DecAll
30
25
20
15
10
5
0
Kyushu-5
Kant o -10
Annual
Feb
Apr
Jun
Aug
Oct
JP10
DecAll
Kyushu
Kant o
Figure 2. Monthly climatology of precipitation and
surface air temperature averaged over the nine
AMeDAS regions.
Figure 5. Same as Figure 3, but for precipitation.
1963/01
1960/12-61/01
74/01
76/12-77/02
80/12-81/01 85/01
84/01-02 86/01
No especially hazardous
event observed
2005/12
Figure 3. Daily variations of surface wind
components, air temperature, and precipitation of
AMeDAS observation (blue) and JP10 (red) in
Okinawa Island.
Figure 6. JP10 monthly mean SWE averaged over
all Honshu Island and historical hazardous snow
events.