• 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, Y-L., 1993: Some synoptic-scale aspects of the surface fronts over southern China during TAMEX. Mon. Wea. Rev, 121 , 5064.

  • Chen, Y-L., and N. B-F. Hui, 1990: Analysis of a shallow front during the Taiwan Area Mesoscale Experiment. Mon. Wea. Rev, 118 , 26492667.

    • Search Google Scholar
    • Export Citation
  • Chen, Y-L., and N. B-F. Hui, 1992: Analysis of a relative dry front during the Taiwan Area Mesoscale Experiment. Mon. Wea. Rev, 120 , 24422468.

    • Search Google Scholar
    • Export Citation
  • Chen, Y-L., and J. Li, 1995: Characteristics of surface airflow and pressure patterns over the island of Taiwan during TAMEX. Mon. Wea. Rev, 123 , 695716.

    • Search Google Scholar
    • Export Citation
  • Chen, Y-L., Y-X. Zhang, and N. B-F. Hui, 1989: Analysis of a surface front during the early summer rainy season over Taiwan. Mon. Wea. Rev, 117 , 909931.

    • Search Google Scholar
    • Export Citation
  • Cho, H. R., and G. T. J. Chen, 1995: Mei-yu frontogenesis. J. Atmos. Sci, 52 , 21092120.

  • Graf, J., C. Sasaki, C. Winn, W. T. Liu, W. Tsai, M. Freilich, and D. Long, 1998: NASA Scatterometer Experiment. Asta Astronaut, 43 , 397407.

    • Search Google Scholar
    • Export Citation
  • Kummerow, C., and and Coauthors, 2000: The status of the Tropical Rainfall Measuring Mission (TRMM) after two years in orbit. J. Appl. Meteor, 39 , 19651982.

    • Search Google Scholar
    • Export Citation
  • Kuo, Y-H., and G. T-J. Chen, 1990: The Taiwan Area Mesoscale Experiments: An overview. Bull. Amer. Meteor. Soc, 71 , 488503.

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

  • Lin, Y-L., N-L. Lin, and R. P. Weglarz, 1992: Numerical modeling studies of lee mesolows, mesovortices, and mesocyclones with application to the formation of Taiwan mesoscales. Meteor. Atmos. Phys, 49 , 4049.

    • Search Google Scholar
    • Export Citation
  • Liu, W. T., W. Tang, and P. Polito, 1998: NASA scatterometer provides global ocean-surface wind fields with more structures than numerical weather prediction. Geophys. Res. Lett, 25 , 761764.

    • Search Google Scholar
    • Export Citation
  • Liu, W. T., H. Hu, and S. Yueh, 2000: Interplay between wind and rain observed in Hurricane Floyd. Eos, Trans. Amer. Geophys. Union, 81 , 253257.

    • Search Google Scholar
    • Export Citation
  • Maddox, R. A., 1980: An objective technique for separating macroscale and mesoscale features in meteorological data. Mon. Wea. Rev, 108 , 11081121.

    • Search Google Scholar
    • Export Citation
  • Ray, P. S., A. Robinson, and Y. Lin, 1991: Radar analysis of a TAMEX frontal system. Mon. Wea. Rev, 119 , 25192539.

  • Schlatter, T. W., G. W. Branstator, and L. G. Thiel, 1976: Testing a global multivariate statistical objective analysis scheme with observed data. Mon. Wea. Rev, 104 , 765783.

    • Search Google Scholar
    • Export Citation
  • Smith, R. B., 1982: Synoptic observations and theory of orographically disturbed wind and pressure. J. Atmos. Sci, 39 , 348364.

  • Sun, W-Y., C-C. Wu, and W-R. Hsu, 1991: Numerical simulation of mesoscale circulation in Taiwan and surrounding area. Mon. Wea. Rev, 119 , 25582573.

    • Search Google Scholar
    • Export Citation
  • Tao, S., and L. Chen, 1987: A review of recent research on the east Asia summer monsoon in China. Monsoon Meteorology, C.-P. Chang and T. N. Krishnamurti, Eds., Oxford University Press, 60–92.

    • Search Google Scholar
    • Export Citation
  • Trier, S. B., D. B. Parsons, and T. J. Matejka, 1990: Observations of a subtropical cold front in a region of complex terrain. Mon. Wea. Rev, 118 , 24492470.

    • Search Google Scholar
    • Export Citation
  • Yeh, H-C., and Y-L. Chen, 1998: Characteristics of rainfall distribution over Taiwan during TAMEX. J. Appl. Meteor, 37 , 14571469.

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Kinematic Characteristics of a Mei-yu Front Detected by the QuikSCAT Oceanic Winds

Hsi-Chyi YehDepartment of Computer and Information Sciences, Aletheia University, Tamshui, Taipei, Taiwan

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George Tai-Jen ChenDepartment of Atmospheric Sciences, National Taiwan University, Taipei, Taiwan

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W. Timothy LiuJet Propulsion Laboratory, California Institute of Technology, Pasadena, California

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Abstract

Based on conventional surface observations and NASA Quick Scatterometer (QuikSCAT) data, a heavy rainfall event that occurred in the Taiwan mei-yu season was chosen to further study the kinematic characteristics of the accompanying surface front. With the help of the QuikSCAT oceanic surface winds, it was found that the location and propagation of a mei-yu front over the ocean to the east of Taiwan during 10–12 June 2000 are better represented by the frontal wind shift line, which was located approximately on the leading edge of the baroclinic zone.

The mesoscale system with cyclonic circulation embedded within the frontal zone was clearly shown in the wind field and kinematic parameters (horizontal divergence and vorticity) as well as satellite clouds and rainfall estimations. The conditional instability of the second kind (CISK) process was suggested to be responsible for the intensification of the mei-yu front and the frontal disturbance over the ocean. Under the influence of island topography over Taiwan and the mountains over southern China, the frontal wind shift line distorted and receded within the Taiwan Strait after the mei-yu front reached northern Taiwan. In the later period, the front moved southward faster to the area immediately east of Taiwan as compared to that over southwestern Taiwan and the Taiwan Strait due to earlier arrival of strong postfrontal northerly winds. The localized southwesterly jetlike feature was observed to the southeast of Taiwan and persisted until the arrival of the strong northerly winds. These localized phenomena were detected by the QuikSCAT oceanic winds.

Corresponding author address: Dr. George Tai-Jen Chen, Department of Atmospheric Sciences, National Taiwan University, 61, Ln. 144, Sec. 4, Keelung Rd., Taipei 10772, Taiwan. Email: george@atmos0.as.ntu.edu.tw

Abstract

Based on conventional surface observations and NASA Quick Scatterometer (QuikSCAT) data, a heavy rainfall event that occurred in the Taiwan mei-yu season was chosen to further study the kinematic characteristics of the accompanying surface front. With the help of the QuikSCAT oceanic surface winds, it was found that the location and propagation of a mei-yu front over the ocean to the east of Taiwan during 10–12 June 2000 are better represented by the frontal wind shift line, which was located approximately on the leading edge of the baroclinic zone.

The mesoscale system with cyclonic circulation embedded within the frontal zone was clearly shown in the wind field and kinematic parameters (horizontal divergence and vorticity) as well as satellite clouds and rainfall estimations. The conditional instability of the second kind (CISK) process was suggested to be responsible for the intensification of the mei-yu front and the frontal disturbance over the ocean. Under the influence of island topography over Taiwan and the mountains over southern China, the frontal wind shift line distorted and receded within the Taiwan Strait after the mei-yu front reached northern Taiwan. In the later period, the front moved southward faster to the area immediately east of Taiwan as compared to that over southwestern Taiwan and the Taiwan Strait due to earlier arrival of strong postfrontal northerly winds. The localized southwesterly jetlike feature was observed to the southeast of Taiwan and persisted until the arrival of the strong northerly winds. These localized phenomena were detected by the QuikSCAT oceanic winds.

Corresponding author address: Dr. George Tai-Jen Chen, Department of Atmospheric Sciences, National Taiwan University, 61, Ln. 144, Sec. 4, Keelung Rd., Taipei 10772, Taiwan. Email: george@atmos0.as.ntu.edu.tw

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