• Akaeda, K., J. Reisner, and D. Parsons, 1995: The role of mesoscale and topographically induced circulations in initiating a flash flood observed during the TAMEX project. Mon. Wea. Rev., 123 , 17201739.

    • Search Google Scholar
    • Export Citation
  • Akiyama, T., 1973: The large-scale aspects of the characteristic features of Baiu front. Pap. Meteor. Geophys., 24 , 157188.

  • Asselin, R., 1972: Frequency filter for time integrations. Mon. Wea. Rev., 100 , 487490.

  • Baines, P. G., 1995: Topographic Effects in Stratified Flows. Cambridge University Press, 482 pp.

  • Banta, R. M., 1990: The role of mountain flows in making clouds. Atmospheric Processes over Complex Terrain, Meteor. Monogr., No. 45, Amer. Meteor. Soc., 229–284.

    • Search Google Scholar
    • Export Citation
  • Bluestein, H. B., and M. H. Jain, 1985: Formation of mesoscale lines of precipitation: Severe squall lines in Oklahoma during the spring. J. Atmos. Sci., 42 , 17111732.

    • Search Google Scholar
    • Export Citation
  • Blumen, W., 1990: Atmospheric Processes over Complex Terrain. Meteor. Monogr. , No. 45, Amer. Meteor. Soc., 323 pp.

  • Bousquet, O., and B. F. Smull, 2003: Observations and impacts of upstream blocking during a widespread orographic precipitation event. Quart. J. Roy. Meteor. Soc., 129 , 391409.

    • Search Google Scholar
    • Export Citation
  • Braun, S. A., R. A. Houze Jr., and B. F. Smull, 1997: Airborne dual-Doppler observations of an intense frontal system approaching the Pacific Northwest coast. Mon. Wea. Rev., 125 , 31313156.

    • Search Google Scholar
    • Export Citation
  • Browning, K. A., 1990: Organization of clouds and precipitation in extratropical cyclones. Extratropical Cyclones: The Erik Palmén Memorial Volume, C. W. Newton and E. O. Holopanien, Eds., Amer. Meteor. Soc., 129–153.

    • Search Google Scholar
    • Export Citation
  • Carbone, R. E., 1982: A severe frontal rainband. Part I: Stormwide hydrodynamic structure. J. Atmos. Sci., 39 , 258279.

  • Chen, G. T-J., 1992: Mesoscale features observed in the Taiwan Mei-Yu season. J. Meteor. Soc. Japan, 70 , 497516.

  • Chen, G. T-J., and C. P. Chang, 1980: The structure and vorticity budget of an early summer monsoon trough (Mei-Yu) over southeastern China and Japan. Mon. Wea. Rev., 108 , 942953.

    • Search Google Scholar
    • Export Citation
  • Chen, G. T-J., and H-C. Chou, 1993: General characteristics of squall lines observed in TAMEX. Mon. Wea. Rev., 121 , 726733.

  • Chien, F-C., C. F. Mass, and P. J. Neiman, 2001: An observational and numerical study of an intense landfalling cold front along the northwest coast of the United States during COAST IOP 2. Mon. Wea. Rev., 129 , 934955.

    • Search Google Scholar
    • Export Citation
  • Colle, B. A., B. F. Smull, and M-J. Yang, 2002: Numerical simulations of a landfalling cold front observed during COAST: Rapid evolution and responsible mechanisms. Mon. Wea. Rev., 130 , 19451966.

    • Search Google Scholar
    • Export Citation
  • Cotton, W. R., G. J. Tripoli, R. M. Rauber, and E. A. Mulvihill, 1986: Numerical simulation of the effects of varying ice crystal nucleation rates and aggregation processes on orographic snowfall. J. Climate Appl. Meteor., 25 , 16581680.

    • Search Google Scholar
    • Export Citation
  • Courtier, P., J-N. Thepaut, and A. Hollingsworth, 1994: A strategy for operational implementation of 4-D-VAR using an incremental approach. Quart. J. Roy. Meteor. Soc., 120 , 13671388.

    • Search Google Scholar
    • Export Citation
  • Doyle, J. D., 1997: The influence of mesoscale orography on a coastal jet and rainband. Mon. Wea. Rev., 125 , 14651488.

  • Grossman, R. L., and D. R. Durran, 1984: Interaction of low-level flow with the Western Ghat Mountains and offshore convection in the summer monsoon. Mon. Wea. Rev., 112 , 652672.

    • Search Google Scholar
    • Export Citation
  • Houze Jr., R. A., B. F. Smull, and P. Dodge, 1990: Mesoscale organization of springtime rainstorms in Oklahoma. Mon. Wea. Rev., 118 , 613654.

    • Search Google Scholar
    • Export Citation
  • Ikawa, M., and K. Saito, 1991: Description of a nonhydrostatic model developed at the Forecast Research Department of the MRI. MRI Tech. Rep. 28, 238 pp.

  • Kanamitsu, T., K. Tada, T. Kudo, N. Sato, and S. Isa, 1983: Description of the JMA operational spectral model. J. Meteor. Soc. Japan, 61 , 812828.

    • Search Google Scholar
    • Export Citation
  • Kato, K., 1985: On the abrupt change in the structure of the Baiu front over the China continent in late May of 1979. J. Meteor. Soc. Japan, 63 , 2035.

    • Search Google Scholar
    • Export Citation
  • Klemp, J. B., and R. B. Wilhelmson, 1978: The simulation of three-dimensional convective storm dynamics. J. Atmos. Sci., 35 , 10701096.

    • Search Google Scholar
    • Export Citation
  • Kondo, J., 1976: Heat balance of the China Sea during the air mass transformation experiment. J. Meteor. Soc. Japan, 54 , 382398.

  • Kuo, Y-H., and G. T-J. Chen, 1990: The Taiwan Area Mesoscale Experiment: An overview. Bull. Amer. Meteor. Soc., 71 , 488503.

  • LeMone, M. A., E. J. Zipser, and S. B. Trier, 1998: The role of environmental shear and thermodynamic conditions in determining the structure and evolution of mesoscale convective systems during TOGA COARE. J. Atmos. Sci., 55 , 34933518.

    • Search Google Scholar
    • Export Citation
  • Li, J., and Y-L. Chen, 1998: Barrier jets during TAMEX. Mon. Wea. Rev., 126 , 959971.

  • Lin, Y-J., R. W. Paskin, and H-W. Chang, 1992: The structure of a subtropical prefrontal convective rainband. Part I: Mesoscale kinematic structure determined from dual-Doppler measurements. Mon. Wea. Rev., 120 , 18161836.

    • Search Google Scholar
    • Export Citation
  • Lin, Y-L., 1993: Orographic effects on airflow and mesoscale weather systems over Taiwan. Terr. Atmos. Ocean Sci., 4 , 381420.

  • Lin, Y-L., R. D. Farley, and H. D. Orville, 1983: Bulk parameterization of the snow field in a cloud model. J. Climate Appl. Meteor., 22 , 10651092.

    • Search Google Scholar
    • Export Citation
  • Liu, A. Q., G. W. K. Moore, K. Tsuboki, and I. A. Renfrew, 2004: A high-resolution simulation of convective roll clouds during a cold-air outbreak. Geophys. Res. Lett., 31 .L03101, doi:10.1029/2003GL018530.

    • Search Google Scholar
    • Export Citation
  • Louis, J. F., M. Tiedtke, and J. F. Geleyn, 1981: A short history of the operational PBL parameterization at ECMWF. Proc. Workshop on Planetary Boundary Layer Parameterization, Reading, United Kingdom, ECMWF, 59–79.

  • Medina, S., and R. A. Houze Jr., 2003: Air motions and precipitation growth in alpine storms. Quart. J. Roy. Meteor. Soc., 129 , 345371.

    • Search Google Scholar
    • Export Citation
  • Mellor, G. L., and T. Yamada, 1974: A hierarchy of turbulent closure models for planetary boundary layers. J. Atmos. Sci., 31 , 17911806.

    • Search Google Scholar
    • Export Citation
  • Murakami, M., 1990: Numerical modeling of dynamical and microphysical evolution of an isolated convective cloud—The 19 July 1981 CCOPE cloud. J. Meteor. Soc. Japan, 68 , 107128.

    • Search Google Scholar
    • Export Citation
  • Murakami, M., T. L. Clark, and W. D. Hall, 1994: Numerical simulations of convective snow clouds over the Sea of Japan: Two-dimensional simulation of mixed layer development and convective snow cloud formation. J. Meteor. Soc. Japan, 72 , 4362.

    • Search Google Scholar
    • Export Citation
  • Neiman, P. J., P. O. G. Persson, F. M. Ralph, D. P. Jorgensen, A. B. White, and D. E. Kingsmill, 2004: Modification of fronts and precipitation by coastal blocking during an intense landfalling winter storm in southern California: Observations during CALJET. Mon. Wea. Rev., 132 , 242273.

    • Search Google Scholar
    • Export Citation
  • Oh, J-H., K. Tsuboki, T-H. Kim, and D-Y. Kang, 2004: Numerical simulation of a strong wind event occurred by typhoon ‘Maemi’ during Sep. 12-13, 2003. Proc. First Annual Meeting, Singapore, Asia Oceania Geosciences Society, 539–540.

  • Onogi, K., 1998: A data quality control method using horizontal gradient and tendency in a NWP system: Dynamic QC. J. Meteor. Soc. Japan, 76 , 497516.

    • Search Google Scholar
    • Export Citation
  • Overland, J. E., and B. A. Bond, 1995: Observations and scale analysis of a coastal wind jet. Mon. Wea. Rev., 123 , 29342941.

  • Pierrehumbert, R. T., 1984: Linear results on the barrier effects of mesoscale mountains. J. Atmos. Sci., 41 , 13561367.

  • Pierrehumbert, R. T., and B. Wyman, 1985: Upstream effects of mesoscale mountains. J. Atmos. Sci., 42 , 9771003.

  • Richard, E., S. Cosma, P. Tabary, J-P. Pinty, and M. Hagen, 2003: High-resolution numerical simulations of the convective system observed in the Lago Maggiore area on 17 September 1999 (MAP IOP 2a). Quart. J. Roy. Meteor. Soc., 129 , 543563.

    • Search Google Scholar
    • Export Citation
  • Rotunno, R., and R. Ferretti, 2003: Orographic effects on rainfall in MAP cases IOP 2b and IOP 8. Quart. J. Roy. Meteor. Soc., 129 , 373390.

    • Search Google Scholar
    • Export Citation
  • Segami, A., K. Kurihara, H. Nakamura, M. Ueno, I. Takano, and Y. Tatsumi, 1989: Operational mesoscale weather prediction with Japan Spectral Model. J. Meteor. Soc. Japan, 67 , 907923.

    • Search Google Scholar
    • Export Citation
  • Smith, R. B., 1982: Synoptic observations and theory of orographically disturbed wind and pressure. J. Atmos. Sci., 39 , 6070.

  • Smolarkiewicz, P. K., R. M. Rasmussen, and T. L. Clark, 1988: On the dynamics of Hawaiian cloud bands: Island forcing. J. Atmos. Sci., 45 , 18721905.

    • Search Google Scholar
    • Export Citation
  • Steiner, M., O. Bousquet, R. A. Houze Jr., B. F. Smull, and M. Mancini, 2003: Airflow within major alpine river valleys under heavy rainfall. Quart. J. Roy. Meteor. Soc., 129 , 411431.

    • Search Google Scholar
    • Export Citation
  • Trier, S. B., and D. B. Parsons, 1995: Updraft dynamics within a numerically simulated subtropical rainband. Mon. Wea. Rev., 123 , 3958.

    • Search Google Scholar
    • Export Citation
  • Tsuboki, K., 2004: High-resolution modeling of localized heavy rain associated with mesoscale convective systems during the Baiu season. Proc. First Annual Meeting, Singapore, Asia Oceania Geosciences Society, 517–518.

  • Tsuboki, K., and A. Sakakibara, 2001: CReSS user’s guide (in Japanese). 2d ed. 210 pp.

  • Tsuboki, K., and A. Sakakibara, 2002: Large-scale parallel computing of cloud resolving storm simulator. High Performance Computing, H. P. Zima et al., Eds., Springer, 243–259.

    • Search Google Scholar
    • Export Citation
  • Tsuyuki, T., and T. Fujita, Eds. 2002: Outline of the operational numerical weather prediction at the Japanese Meteorological Agency. JMA, 157 pp.

  • Wang, C-C., and G. T-J. Chen, 2003: On the formation of leeside mesolows under different Froude number flow regime in TAMEX. J. Meteor. Soc. Japan, 81 , 339365.

    • Search Google Scholar
    • Export Citation
  • Wang, T-C. C., Y-J. Lin, R. W. Paskin, and H. Shen, 1990: Characteristics of a subtropical squall line determined from TAMEX dual-Doppler data. Part I: Kinematic structure. J. Atmos. Sci., 47 , 23572381.

    • Search Google Scholar
    • Export Citation
  • Yeh, H-C., and Y-L. Chen, 2002: The role of offshore convergence on coastal rainfall during TAMEX IOP 3. Mon. Wea. Rev., 130 , 27092730.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 243 179 4
PDF Downloads 182 121 2

A Numerical Study on the Effects of Taiwan Topography on a Convective Line during the Mei-Yu Season

View More View Less
  • 1 Department of Environmental Management, Jin-Wen Institute of Technology, Taipei, Taiwan
  • | 2 Department of Atmospheric Sciences, National Taiwan University, Taipei, Taiwan
  • | 3 Department of Atmospheric Sciences, National Taiwan University, and Central Weather Bureau, Taipei, Taiwan
  • | 4 Hydrospheric Atmospheric Research Center, Nagoya University, Nagoya, Japan
Restricted access

Abstract

During the morning hours on 23 May 2002, a convective line associated with a mei-yu front brought heavy rainfall along the coast of central Taiwan under favorable synoptic conditions of warm air advection and large convective available potential energy (CAPE) of over 3000 m2 s−2. Doppler radar observations indicated that deep convection was organized into a linear shape with a northeast–southwest orientation along the front about 70 km offshore from Taiwan over the northern Taiwan Strait. The system then moved toward Taiwan at a slow speed of about 4 m s−1. In the present study, the effects of Taiwan topography on this convective line and subsequent rainfall distribution were investigated through numerical modeling using the Nagoya University Cloud-Resolving Storm Simulator (CReSS) at a 2-km horizontal grid size. Experiments with different terrain heights of Taiwan, including full terrain (FTRN), half terrain (HTRN), and no terrain (NTRN), were performed. The control run using full-terrain and cold rain explicit microphysics realistically reproduced the evolution of the convective line and the associated weather with many fine details.

Two low-level convergence zones were found to be crucial in the development of this convective line and the subsequent rainfall distribution over Taiwan. The first was along the mei-yu front and forced mainly by the front, but was terrain enhanced off the northwestern coast of Taiwan due to the blocking of air on the windward side of the Central Mountain Range (CMR). After formation, convective cells along this zone propagated southeastward and produced rainfall over the northwestern coast. As the front moved closer to Taiwan, a second arc-shaped convergence zone with a nearly north–south orientation along about 120°E formed ahead of the front between the prevailing flow and near-surface offshore flow induced by the blocking. This second zone was terrain induced, and convection initiated near its northern end was found to be responsible for the rainfall maximum observed near the coast of central Taiwan. Its intensity and position were highly sensitive to terrain height. In the HTRN run where the terrain was reduced by half, a weaker zone closer to the CMR (by about 50 km) was produced, and the rain fell mostly over the windward slope of the terrain instead of over the coastal plain. When the terrain was removed in the NTRN run, no such zone with the correct orientation formed. It was also found that the frontal movement near northern Taiwan was slightly delayed with the presence of terrain, and this affected the timing and distribution of local rainfall during the later stages of this event.

* Current affiliation: Department of Atmospheric Sciences, Chinese Culture University, Taipei, Taiwan

Corresponding author address: Prof. George Tai-Jen Chen, Department of Atmospheric Sciences, National Taiwan University, No. 61, Ln. 144, Sec. 4, Keelung Rd., Taipei 10772, Taiwan. Email: george@george2.as.ntu.edu.tw

Abstract

During the morning hours on 23 May 2002, a convective line associated with a mei-yu front brought heavy rainfall along the coast of central Taiwan under favorable synoptic conditions of warm air advection and large convective available potential energy (CAPE) of over 3000 m2 s−2. Doppler radar observations indicated that deep convection was organized into a linear shape with a northeast–southwest orientation along the front about 70 km offshore from Taiwan over the northern Taiwan Strait. The system then moved toward Taiwan at a slow speed of about 4 m s−1. In the present study, the effects of Taiwan topography on this convective line and subsequent rainfall distribution were investigated through numerical modeling using the Nagoya University Cloud-Resolving Storm Simulator (CReSS) at a 2-km horizontal grid size. Experiments with different terrain heights of Taiwan, including full terrain (FTRN), half terrain (HTRN), and no terrain (NTRN), were performed. The control run using full-terrain and cold rain explicit microphysics realistically reproduced the evolution of the convective line and the associated weather with many fine details.

Two low-level convergence zones were found to be crucial in the development of this convective line and the subsequent rainfall distribution over Taiwan. The first was along the mei-yu front and forced mainly by the front, but was terrain enhanced off the northwestern coast of Taiwan due to the blocking of air on the windward side of the Central Mountain Range (CMR). After formation, convective cells along this zone propagated southeastward and produced rainfall over the northwestern coast. As the front moved closer to Taiwan, a second arc-shaped convergence zone with a nearly north–south orientation along about 120°E formed ahead of the front between the prevailing flow and near-surface offshore flow induced by the blocking. This second zone was terrain induced, and convection initiated near its northern end was found to be responsible for the rainfall maximum observed near the coast of central Taiwan. Its intensity and position were highly sensitive to terrain height. In the HTRN run where the terrain was reduced by half, a weaker zone closer to the CMR (by about 50 km) was produced, and the rain fell mostly over the windward slope of the terrain instead of over the coastal plain. When the terrain was removed in the NTRN run, no such zone with the correct orientation formed. It was also found that the frontal movement near northern Taiwan was slightly delayed with the presence of terrain, and this affected the timing and distribution of local rainfall during the later stages of this event.

* Current affiliation: Department of Atmospheric Sciences, Chinese Culture University, Taipei, Taiwan

Corresponding author address: Prof. George Tai-Jen Chen, Department of Atmospheric Sciences, National Taiwan University, No. 61, Ln. 144, Sec. 4, Keelung Rd., Taipei 10772, Taiwan. Email: george@george2.as.ntu.edu.tw

Save