• 제목/요약/키워드: Atmospheric environment effect

검색결과 619건 처리시간 0.052초

풍력 발전 예보 정확도 향상을 위한 국지 기상장 수치모의 개선 방안 연구 (A Study on Effect of Improvement Plan for Wind Energy Forecasting)

  • 정지아;이화운;전원배;김동혁;김현구;강용혁
    • 한국대기환경학회지
    • /
    • 제31권1호
    • /
    • pp.1-14
    • /
    • 2015
  • This study investigates the impact of enhanced regional meteorological fields on improvement of wind energy forecasting accuracy in the southwestern coast of the Korean Peninsula. To clarify the effect of detailed surface boundary data and application of analysis nudging technique on simulated meteorological fields, several WRF simulations were carried out. Case_LT, which is a simulation with high resolution terrain height and land use data, shows the most remarkable accuracy improvement along the shoreline mainly due to modified surface characteristics such as albedo, roughness length and thermal inertia. Case_RS with high resolution SST data shows accurate SST distributions compared to observation data, and they led to change in land and sea breeze circulation. Case_GN, grid nudging applied simulation, also shows changed temperature and wind fields. Especially, the application of grid nudging dominantly influences on the change of horizontal wind components in comparison with vertical wind component.

한반도 주변에서 MODIS와 NCEP/NCAR 재분석 자료를 이용한 에어로졸과 구름의 연관성 분석 (An Analysis of Aerosol-Cloud Relationship Using MODIS and NCEP/NCAR Reanalysis Data around Korea)

  • 김유준;이진화;김병곤
    • 한국대기환경학회지
    • /
    • 제27권2호
    • /
    • pp.152-167
    • /
    • 2011
  • MODIS/Terra level 3 and NCEP/NCAR Reanalysis data from 2001 to 2008 have been analyzed to understand long-term aerosol and cloud optical properties, and their relationships around Korea. Interestingly, cloud fraction(CF) has the similar annual variation to aerosol optical depth (${\tau}_a$) without any temporal significant trend. Horizontal distributions of ${\tau}_a$ showed the substantial horizontal gradient from China to Korea, especially with the strong difference over the Yellow Sea, which could represent the evidence of the anthropogenic influence from China in the perspective of long-term average. Specifically the negative correlations between ${\tau}_a$ and liquid-phase cloud effective radius ($r_e$) were shown on the monthly-average basis, only in summer with significant associations over the Yellow Sea, but not in the other seasons and/or specific regions. Relationship between ${\tau}_a$ and CF for the low-level liquid-phase clouds exhibited the overall positive correlation, being consistent with cloud lifetime effect. Meanwhile static stability showed no deterministic relationships with ${\tau}_a$ as well as CF. The dependence of aerosol-cloud relationship on the meteorological conditions should be examined more in detail with the satellite remote sensing and reanalysis data.

지표 에너지 수지에 미치는 구름의 복사 역할 (Radiative Role of Clouds on the Earth Surface Energy Balance)

  • 홍성철;정일웅;김형진;이재범;오성남
    • 한국환경과학회지
    • /
    • 제16권3호
    • /
    • pp.261-267
    • /
    • 2007
  • In this study, the Slab Ocean Model (SOM) is coupled with an Atmospheric General Circulation Model (AGCM) which developed in University of Kangnung based on the land surface model of Biosphere-Atmosphere Transfer Scheme (BATS). The purposes of this study are to understand radiative role of clouds considering of the atmospheric feedback, and to compare the Clouds Radiative Forcing (CRF) come from the analyses using the clear-cloud sky method and CGCM. The new CGCM was integrated by using two sets of the clouds with radiative role (EXP-A) and without radiative role (EXP-B). Clouds in this two cases show the negative effect $-26.0\;Wm^{-2}$ of difference of radiation budget at top of atmosphere (TOA). The annual global means radiation budget of this simulation at TOA is larger than the estimations ($-17.0 Wm^{-2}$) came from Earth Radiation Budget Experiment (ERBE). The work showed the surface negative effect with $-18.6 Wm^{-2}$ in the two different simulations of CRF. Otherwise, sensible heat flux in the simulation shows a great contribution with positive forcing of $+24.4 Wm^{-2}$. It is found that cooling effect to the surface temperature due to radiative role of clouds is about $7.5^{\circ}C$. From this study it could make an accurate of the different CRF estimation considering either feedback of EXP-B or not EXP-A under clear-sky and cloud-sky conditions respectively at TOA. This result clearly shows its difference of CRF $-11.1 Wm^{-2}$.

Numerical Simulations of Dry and Wet Deposition over Simplified Terrains

  • Michioka, T.;Takimoto, H.;Ono, H.;Sato, A.
    • Asian Journal of Atmospheric Environment
    • /
    • 제11권4호
    • /
    • pp.270-282
    • /
    • 2017
  • To evaluate the deposition amount on a ground surface, mesoscale numerical models coupled with atmospheric chemistry are widely used for larger horizontal domains ranging from a few to several hundreds of kilometers; however, these models are rarely applied to high-resolution simulations. In this study, the performance of a dry and wet deposition model is investigated to estimate the amount of deposition via computational fluid dynamics (CFD) models with high grid resolution. Reynolds-averaged Navier-Stokes (RANS) simulations are implemented for a cone and a two-dimensional ridge to estimate the dry deposition rate, and a constant deposition velocity is used to obtain the dry deposition flux. The results show that the dry deposition rate of RANS generally corresponds to that observed in wind-tunnel experiments. For the wet deposition model, the transport equation of a new scalar concentration scavenged by rain droplets is developed and used instead of the scalar concentration scavenged by raindrops falling to the ground surface just below the scavenging point, which is normally used in mesoscale numerical models. A sensitivity analysis of the proposed wet deposition procedure is implemented. The result indicates the applicability of RANS for high-resolution grids considering the effect of terrains on the wet deposition.