• 한국지구과학회지
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• 제32권4호
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• pp.373-387
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• 2011

본 연구에서는 CORDEX 동아시아 영역에서 경계조건(ERA-Interim, NCEP/DOE2) 및 적운모수화방안(Grell, Emanuel)이 2010년 7월에 공개된 지역기후모델(RegCM4)의 모의성능에 미치는 영향을 평가하기 위해 1989년에 대해 총 4개의 민감도 실험(EG, EE, NG, NE)을 수행하였다. 남한에서의 기온, 강수에 대한 RegCM4의 모의성능을 분석하기 위해 기상청의 기온, 강수자료를 이용하였다. RegCM4는 경계조건 및 적운모수화방안에 관계없이 기온의 공간분포, 계절변동을 잘 모의한 반면, 모든 실험에서 강수의 시 공간 분포를 적절히 모의하지 못하였다. 특히, EG, NG, NE 실험은 여름 강수를 관측보다 현저히 적게 모의하는 등 강수의 계절변동을 전혀 모의하지 못하고 있다. 하지만 EE 실험에서는 여름 강수를 포함하여 계절변동을 상대적으로 잘 모의하였다. 동아시아 여름 몬순 및 강수강도별 강수량, 강수빈도 모의에서도 EE 실험이 우수한 모의성능을 보였다. RegCM4는 경계조건에 관계없이 기온, 강수 모두 여름보다는 겨울에, Grell 보다는 Emanuel 방안을 적용할 때 높은 모의성능을 보였다. 또한 전체적으로 모의성능은 경계조건보다는 적운모수화방안에 더 큰 영향을 받는다.

• 대기
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• 제21권4호
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• pp.391-404
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• 2011

This study investigates the impact of cumulus parameterization scheme (CPS) with different horizontal grid sizes on the simulation of the local heavy rainfall case over the Korean Peninsula. The Weather Research and Forecasting (WRF)-based real-time forecast system of the Joint Center for High-impact Weather and Climate Research (JHWC) is used. Three CPSs are used for sensitivity experiments: the BMJ (Betts-Miller-Janjic), GD (Grell-Devenyi ensemble), and KF (Kain-Fritsch) CPSs. The heavy rainfall case selected in this study is characterized by low-level jet and low-level transport of warm and moist air. In 27-km simulations (DM1), simulated precipitation is overestimated in the experiment with BMJ scheme, and it is underestimated with GD scheme. The experiment with KF scheme shows well-developed precipitation cells in the southern and the central region of the Korean Peninsula, which are similar to the observations. All schemes show wet bias and cold bias in the lower troposphere. The simulated rainfall in 27-km horizontal resolution has influence on rainfall forecast in 9-km horizontal resolution, so the statements on 27-km horizontal resolution can be applied to 9-km horizontal resolution. In the sensitivity experiments of CPS for DM3 (3-km resolution), the experiment with BMJ scheme shows better heavy rainfall forecast than the other experiments. The experiments with CPS in 3-km horizontal resolution improve rainfall forecasts compared to the experiments without CPS, especially in rainfall distribution. The experiments with CPS show lower LCL(Lifted Condensation Level) than those without CPS at the maximum rainfall point, and weaker vertical velocity is simulated in the experiments with CPS compared to the experiments without CPS. It means that CPS suppresses convective instability and influences mainly convective rainfall. Consequently, heavy rainfall simulation with BMJ CPS is better than the other CPSs, and even in 3-km horizontal resolution, CPS should be applied to control convective instability. This conclusion can be generalized by conducting more experiments for a variety of cases over the Korean Peninsula.

• 대기
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• 제27권1호
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• pp.105-118
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• 2017

This study assesses the performance of the Weather Research and Forecasting (WRF) model in reproducing regional climate over CORDEX-East Asia Phase 2 domain with different cumulus parameterization schemes [Kain-Fritch (KF), Betts-Miller-Janjic (BM), and Grell-Devenyi-Ensemble (GD)]. The model is integrated for 27 months from January 1979 to March 1981 and the initial and boundary conditions are derived from European Centre for Medium-Range Weather Forecast Interim Reanalysis (ERA-Interim). The WRF model reasonably reproduces the temperature and precipitation characteristics over East Asia, but the regional scale responses are very sensitive to cumulus parameterization schemes. In terms of mean bias, WRF model with BM scheme shows the best performance in terms of summer/winter mean precipitation as well as summer mean temperature throughout the North East Asia. In contrast, the seasonal mean precipitation is generally overestimated (underestimated) by KF (GD) scheme. In addition, the seasonal variation of the temperature and precipitation is well simulated by WRF model, but with an overestimation in summer precipitation derived from KF experiment and with an underestimation in wet season precipitation from BM and GD schemes. Also, the frequency distribution of daily precipitation derived from KF and BM experiments (GD experiment) is well reproduced, except for the overestimation (underestimation) in the intensity range above (less) then $2.5mm\;d^{-1}$. In the case of the amount of daily precipitation, all experiments tend to underestimate (overestimate) the amount of daily precipitation in the low-intensity range < $4mm\;d^{-1}$ (high-intensity range > $12mm\;d^{-1}$). This type of error is largest in the KF experiment.