Geoscience Reference
In-Depth Information
and flooding and severe damage in southeastern Korea for more than
10 days.
2
This naturally led to select a case of monsoon of 2002 for our
studies.
It is well known that the precipitation over Asia varies considerably
from day to day basis. Generally, rain occurs in spell over major parts
under the influence of favorable circulation conditions. This periodical rain-
fall is related to a hierarchy of quasi-periods, namely 3-7 days, 10-20 days,
and 30-60 days oscillations. The 3-7 days periodicity is associated with the
oscillation of low pressure zone (monsoon trough over India, Changma over
Korea, Baiu over Japan, and Meiyu over China), 10-20 and 30-60 days peri-
odicities are associated with the west ward moving waves formed over Bay
of Bengal and the globally eastward moving wave numbers 1 and 2 over the
tropics,
3
respectively. Most of the observational and modeling studies on
the intra-seasonal low-frequency oscillations have focused mainly for south
Asian regions, some studies have done for east Asian regions, but a very few
studies available over South Korea using regional climate model. Hence, in
this study, we have investigated the temporal characteristics of the 10-20
and 30-60 days oscillations to summer precipitation over South Korea using
RegCM3 model with different cumulus parameterization schemes. The mon-
soon of 2002 over South Korea has been selected for this study. We have
focused mainly precipitation fields simulated with RegCM3 because of its
sensitivity to climate. Section 2 describes the details of model and simulated
results are given in Sec. 3. Wavelet analysis of precipitation is presented in
Sec. 4 and conclusions are given in Sec. 5.
2. Model Descriptions
The model used in this study is the recent version of NCAR RegCM3.
4
-
6
The model dynamical core is essentially the same as that of the hydro-
static version of the meso-scale model MM5.
7
The RegCM3 includes the
large scale precipitation scheme,
8
the radiative transfer scheme of the global
model CCM3
9
and the ocean-atmosphere flux scheme.
10
In this study, we
have used three convective parameterization schemes. The first is the sim-
plified Kuo-type parameterization.
7
The second scheme we have used is
also extensively used within both the MM5 and RegCM3 modeling frame
work. This is a mass flux scheme that includes the moistening and heating
effects of penetrative updrafts and corresponding downdrafts. The schemes
have two closer assumptions, the so-called Arakawa-Schubert (AS) and
