호수에 의한 국지 순환의 영향을 조사하기 위하여 대청호수 주변에 대하여 수치 실험을 수행하고 국지 순환의 형태를 연구하였다. WRF 모델로부터 예보된 지상 기온은 관측보다 작으며, 풍속은 모델에서 관측보다 강하게 모의됨을 보였다. 호수 주변의 국지 순환은 호수와 주변 지면과의 열적 차이에 의해 발생하는 호수풍이 특징적이었다. 대청호수에서는 호수풍이 09 LST에 발생하며, 15 LST에 최대를 보이고 18 LST에 소멸하였다. 수치 모의된 연직 순환의 높이는 1,200m를 나타냈다. 비습의 분포는 낮 시간동안 호수풍 순환에 의해 호수위의 습윤한 공기의 내륙 이동으로 주위 지면에서 증가함을 보였다. 호수를 제거한 민감도 실험에서 호수가 존재할 때 주위 지면 온도가 감소함을 보였다. 호수 지표이용도를 초원으로 변경하였을 때 호수 주변의 기상관측소에서 풍속은 증가하였다. 수치실험은 호수로부터 발생된 호수풍 순환이 주위 대기경계층 기상에 영향을 주고 있음을 지시한다.
Mesoscale low is often observed over the downstream region of the East Sea (or, northwest coast off the Japan Islands) during East-Asia winter monsoon. The low system causes a heavy snowfall at the region. A series of numerical experiments were conducted with the aid of a regional model (MM5 ver. 3.5) to examine the formation mechanism of the mesoscale low. The following results were obtained: 1) A well-developed mesoscale low was simulated by the regional model under real topography, NCEP reanalysis, and OISST; 2) The mesoscale low was simulated under a zonally averaged SST without topography. This implies that the meridional gradient of SST is the main factor in the formation of a mesoscale low; 3) A thermal contrast (>10˚C) of land-sea and topography-induced disturbance served as the second important factor for the formation; 4) Paektu Mountain caused the surface wind to decelerate downstream, which created a more favorable environment for thermodynamic modification than that was found in a flat topography; and 5) The types of cumulus parameterizations did not affect the development of the mesoscale low.
In order to clarify the impacts of thermal difference in atmospheric boundary layer due to the different sophistication of building information in Busan metropolitan areas, several numerical simulations were carried out. ACM (Albedo Calculation Model) and WRF (Weather Research and Forecasting) was applied for estimating albedo and meteorological elements in urban area, respectively. In comparison with coarse aggregated and small buildings, diurnal variation of albedo is highly frequent and its total value tend to be smaller in densely aggregated and tall buildings.
Estimated TKE and sensible heat flux with sophisticatedly urban building parameterization is more resonable and valid values are mainly induced by urban building sophistication. The simulation results suggest that decreased albedo and increased roughness due to skyscraper plays an important role in the result of thermal change in atmospheric boundary layer.
The Characteristics of atmospheric flow and dispersion of air pollutants in the mountainous coastal area were studied using two-dimensional model by the combination of land-sea breezes and transport.
The pollutants emitted into the simulated wind field in considering with the mesoscale local circulations. The typical effects of land-sea breezes and tophography of coastal area on the dispersion are discussed in detail, and the model is proved as an useful tool to pridict real time pollutant transport by the results of application studies in Pusan, Korea where the urbanized coastal area with mountainous topography.
It was found that sulfur dioxide (SO2) are differently transported and concentrated as going inland by the influence of the sea breeze with topographic changes.
Dispersion characteristics of air pollutants in the mountainous coastal area are investigated in considering with the mesoscale local circulations using a two dimensional numerical model with two kinds of topograpy of 500m and 300m. In the model, land-sea breezes and mountain-valley wind are mainly considered under the condition of the absence of large scale prevailing flow in the circulation analysis, and the pollutants dispersion is traced by the Lagrangian methods. According to the results, the wind velocity is affected by topography and is stronger in the case of 500m height mountain than that of 300m, the pollutants that source is near the coast transported over the mountain and dispersed to behind inland area. It is classified that the topography change control affects the wind velocity and the circulations. The pollutants that source is different transported and concentrated to behind inland and/or diffused to the sea area by the combination of the wind system with topographic changes. The results can be applied to the air pollution control with the arrangement design of industrial area and the planning of coastal developments.