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the Fritsch-Chappell (FC) type closures. The third scheme is Emanuel 11
(EMU).
The period of RegCM3 simulations are from January to December,
2002 for the purpose of present study. The computation domain covers
area approximately 24 N-48 N and 109 E-148 E with a grid point spacing
at 27 km. For validation of simulated precipitation, daily rainfall data for
59 stations spread over South Korea, are used during summer monsoon
(June-August) in 2002 from Korea Meteorological Administration (KMA).
The observed (KMA) precipitation over 59 stations is interpolated using an
objective analysis 12 to get better spatial details. For examining the intensity
of intra-seasonal oscillations and its temporal variation, Butterworth band
pass filter, 13 with half power points at 10 and 20 days for the quasi-biweekly
oscillations and at 30 and 60 days for the Madden Julian oscillation (MJO)
is applied to the precipitation time series.
3. Simulation of Mean Monsoon Features
The seasonal wind fields simulated by model at lower (850 hPa) and
upper (200 hPa) levels have the maximum strength of tropical southerly
by 6 m/s and upper level westerly of 25 m/s, respectively. This result show
that mean monsoon wind fields at 850 and 200 hPa are in line with the
NCEP/NCAR reanalysis. While spatial distribution of seasonal tempera-
ture fields (850 hPa) shows that RegCM3 seems to be characterized by cold
biases of few degree over some regions. Cold bias in RegCM3 simulation
may be caused by the physical parameterizations such as non-local bound-
ary layer, convection and land surface scheme. 14 A comparison of simulated
temperature and wind patterns with NCEP/NCAR reanalysis fields indi-
cate that the EMU scheme exhibits a better simulation compared to other
convective schemes over east Asia.
Figure 1 shows the precipitation only for the interior of the domain
(mainly over South Korea) in order to more clearly illustrate the fine scale
topographical induced details. Figure 1(a)-(d) shows the precipitation rate
(mm/day) simulated by RegCM3 during summer monsoon season (average
of June-August) using various cumulus convective schemes such as AS, FC,
a Kuo-type, and EMU in RegCM3. Figure 1(e) shows the observed precip-
itation rate (mm/day) from KMA. RegCM3 simulation with AS scheme
shows the maximum precipitation of 12 mm/day over southern Korea and
northeast coast of Korea, while FC scheme shows that the maximum pre-
cipitation of 14 mm/day over southwest parts and 12 mm/day over central
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