Journal of the Korean earth science society (한국지구과학회지)

The Korean Earth Science Society (한국지구과학회)
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Structure and Evolution of a Numerically Simulated Thunderstorm Outflow

수치 모사된 뇌우 유출의 구조와 진화

  • Kim, Yeon-Hee (Forecast Research Laboratory, National Institute of Meteorological Research) ;
  • Baik, Jong-Jin (School of Earth and Environmental Sciences, Seoul National University)
  • 김연희 (국립기상연구소 예보연구팀) ;
  • 백종진 (서울대학교 지구환경과학부)
  • Published : 2007.12.31
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Abstract

The structure and evolution of a thunderstorm outflow in two dimensions with no environmental wind are investigated using a cloud-resolving model with explicit liquid-ice phase microphysical processes (ARPS: Advanced Regional Prediction System). The turbulence structure of the outflow is explicitly resolved with a high-resolution grid size of 50m. The simulated single-cell storm and its associated Kelvin-Helmholtz (KH) billows are found to have the lift stages of development maturity, and decay. The secondary pulsation and splitting of convective cells resulted from interactions between cloud dynamics and microphysics are observed. The cooled downdrafts caused by the evaporation of rain and hail in the relatively dry lower atmosphere result in thunderstorm cold-air outflow. The outflow head propagates with almost constant speed. The KH billows formed by the KH instability cause turbulence mixing from the top of the outflow and control the structure of the outflow. Ihe KH billows are initiated at the outflow head, and pow and decay as moving rearward relative to the gust front. The numerical simulation results of the ratio of the horizontal wavelength of the fastest growing perturbation to the critical shear-layer depth and the ratio of the horizontal wavelength of the billow to its maximum amplitude are matched well with the results of other studies.

명시적 액체-얼음상 미시물리 과정을 포함하는 구름 분해 모형(ARPS: Advanced Regional Prediction System)을 이용하여 2차원 그리고 주변 바람이 없는 경우에 뇌우 유출의 구조와 진화를 조사하였다. 고해상도 격자 간격(50m)을 이용하여 유출의 난류 구조를 명시적으로 분해하였다. 모사된 단세포 스톰과 스톰과 연관된 Kelvin-Helmholtz(KH) 빌로우(billow)는 발달, 성숙, 소멸의 생애 단계를 가졌다. 구름 역학과 미시물리 사이의 상호작용으로 야기된 이차 맥동과 대류 세포의 분활이 관측되었다. 상대적으로 건조한 하층 대기를 낙하하는 빗방울과 우박의 증발에 기인한 찬 하강류는 뇌우 찬 공기 유출을 야기시켰다. 유출 머리는 거의 일정한 속도로 이동하였다. KH 불안정에 의해 생성된 KH 빌로우는 유출 상부에서 난류 혼합을 야기하였으며 유출의 구조를 지배하였다. KH 빌로우는 유출 머리에서 생성되었고 돌풍 전선에 상대적으로 뒤쪽으로 이동함에 따라 성장하고 소멸하였다. 가장 빨리 성장하는 섭동의 수평 파장과 임계 시어층 깊이의 비 그리고 KH 빌로우의 수평 파장과 최대 진폭의 비에 대한 수치 모사 결과는 다른 연구 결과와 잘 일치하였다.

Keywords

References

  1. 김연희, 백종진, 1998, 밀도류에 미치는 배경 안정도의 효과. 한국기상학회지, 34, 154-168
  2. Benjamin, T.B., 1968, Gravity currents and related phenomena. Journal of Fluid Mechanics, 31, 209-248 https://doi.org/10.1017/S0022112068000133
  3. Charba, J., 1974, Application of a gravity current model to analysis of squall line gust front. Monthly Weather Review, 102, 140-156 https://doi.org/10.1175/1520-0493(1974)102<0140:AOGCMT>2.0.CO;2
  4. Chen, C., 1995, Numerical simulations of gravity currents in uniform shear flows. Monthly Weather Review, 123, 3240-3253 https://doi.org/10.1175/1520-0493(1995)123<3240:NSOGCI>2.0.CO;2
  5. Crook, N.A. and Miller, M.J., 1985, A numerical and analytical study of atmospheric undular bores. Quartly Journal of the Royal Meteorological Soceity, 111, 225-242 https://doi.org/10.1256/smsqj.46709
  6. Drazin, P.G., 1958, The stability of a shear layer in an unbounded heterogeneous inviscid fluid. Journal of Fluid Mechanics, 4, 214-224 https://doi.org/10.1017/S0022112058000409
  7. Droegemeier, K.K. and Wilhelmson, R.B., 1987, Simulations of thunderstorm outflow dynamics. Part I: Outflow sensitivity experiments and turbulence dynamics. Journal of the Atmospheric Sciences, 44, 1180-1210 https://doi.org/10.1175/1520-0469(1987)044<1180:NSOTOD>2.0.CO;2
  8. Goff, R.C., 1976, Vertical structure of thunderstorm outflows. Monthly Weather Review, 104, 1429-1440 https://doi.org/10.1175/1520-0493(1976)104<1429:VSOTO>2.0.CO;2
  9. Houze, Jr., R.A., 1993, Cloud dynamics. Academic Press, 573 p
  10. Mahoney III, W.P., 1988, Gust front characteristics and the kinematics associated with interacting thunderstorm outflows. Monthly Weather Review, 116, 1474-1491 https://doi.org/10.1175/1520-0493(1988)116<1474:GFCATK>2.0.CO;2
  11. Miles, J.W and Howard, L.N., 1964, Note on a heterogeneous shear flow. Journal of Fluid Mechanics, 20, 331-336 https://doi.org/10.1017/S0022112064001252
  12. Mitchell, K.E. and Hovermale, J.B., 1977, A numerical investigation of a severe thunderstorm gust front. Monthly Weather Review, 105, 657-675 https://doi.org/10.1175/1520-0493(1977)105<0657:ANIOTS>2.0.CO;2
  13. Mueller, C.K. and Carbone, R.E., 1987, Dynamics of a thunderstorm outflow. Journal of the Atmospheric Sciences, 44, 1879-1898 https://doi.org/10.1175/1520-0469(1987)044<1879:DOATO>2.0.CO;2
  14. Proctor, F.H., 1988, Numerical simulations of an isolated microburst. Part I: Dynamics and structure. Journal of the Atmospheric Sciences, 45, 3137-3160 https://doi.org/10.1175/1520-0469(1988)045<3137:NSOAIM>2.0.CO;2
  15. Proctor, F.H., 1989, Numerical simulations of an isolated microburst. Part II: Sensitivity experiments. Journal of the Atmospheric Sciences, 45, 3137-3160 https://doi.org/10.1175/1520-0469(1988)045<3137:NSOAIM>2.0.CO;2
  16. Seitter, K.L., 1983, The effect of arc cloud generation on thunderstorm gust front motion. Preprints, 13th Conference on Severe Local Storms, Tulsa, American Meteorological Society, 249-252
  17. Simpson, J.E., 1969, A comparison between laboratory and atmospheric density currents. Quartly Journal of the Royal Meteorological Soceity, 95, 758-765 https://doi.org/10.1002/qj.49709540609
  18. Simpson, J.E. and Britter, R.E., 1979, The dynamics of the head of a gravity current advancing over a horizontal surface. Journal of Fluid Mechanics, 94, 477-495 https://doi.org/10.1017/S0022112079001142
  19. Simpson, J.E. and Britter, R.E., 1980, A laboratory model of an atmospheric mesofront. Quartly Journal of the Royal Meteorological Society, 106, 485-500 https://doi.org/10.1002/qj.49710644907
  20. Soong, S.T. and Ogura, Y., 1973, A comparison between axisymmetric and slab-symmetric cumulus cloud models. Journal of the Atmospheric Sciences, 30, 879-893 https://doi.org/10.1175/1520-0469(1973)030<0879:ACBAAS>2.0.CO;2
  21. Wakimoto, R.M., 1982, The life cycle of thunderstorm gust fronts as viewed with Doppler radar and rawinsonde data. Monthly Weather Review, 110, 1060-1082 https://doi.org/10.1175/1520-0493(1982)110<1060:TLCOTG>2.0.CO;2
  22. Weaver, J.F. and Nelson, S.P., 1982, Multiscale aspects of thunderstorm gust fronts and their effects on subsequent storm development. Monthly Weather Review, 110, 707-718 https://doi.org/10.1175/1520-0493(1982)110<0707:MAOTGF>2.0.CO;2
  23. Weisman, M.L. and Klemp, J.B., 1982, The dependence of numerically simulated convective storms on vertical shear and buoyancy. Monthly Weather Review, 110, 504-529 https://doi.org/10.1175/1520-0493(1982)110<0504:TDONSC>2.0.CO;2
  24. Xue, M., Droegemeier, K.K., Wong, V., Shapiro, A., and Brewster, K., 1995, ARPS version 4.0 User's Guide. Center for Analysis and Prediction of Storms, University of Oklahoma, USA, 380 p
  25. Xue, M., Qin, X., and Droegemeier, K.K., 1997, A theoretical and numerical study of density currents in nonconstant shear flows. Journal of the Atmospheric Sciences, 54, 1998-2019 https://doi.org/10.1175/1520-0469(1997)054<1998:ATANSO>2.0.CO;2

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