• Akter, N., and K. Tsuboki, 2012: Numerical simulation of Cyclone Sidr using a cloud-resolving model: Characteristics and formation process of an outer rainband. Mon. Wea. Rev., 140, 789810, https://doi.org/10.1175/2011MWR3643.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Anthes, R. A., Ed., 1982: Tropical Cyclones: Their Evolution, Structure and Effects. Meteor. Monogr., No. 41, Amer. Meteor. Soc., 208 pp.

  • Barnes, G. M., E. J. Zipser, D. P. Jorgensen, and F. D. Marks, 1983: Mesoscale and convective structure of a hurricane rainband. J. Atmos. Sci., 40, 21252137, https://doi.org/10.1175/1520-0469(1983)040<2125:MACSOA>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Bogner, P. B., G. M. Barnes, and J. L. Franklin, 2000: Conditional instability and shear for six hurricanes over the Atlantic Ocean. Wea. Forecasting, 15, 192207, https://doi.org/10.1175/1520-0434(2000)015<0192:CIASFS>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Chen, B.-F., R. L. Elsberry, and C.-S. Lee, 2014: Origin and maintenance of the long-lasting, outer mesoscale convective system in Typhoon Fengshen (2008). Mon. Wea. Rev., 142, 28382859, https://doi.org/10.1175/MWR-D-14-00036.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Chen, Y., and M. K. Yau, 2001: Spiral bands in a simulated hurricane. Part I: Vortex Rossby wave verification. J. Atmos. Sci., 58, 21282145, https://doi.org/10.1175/1520-0469(2001)058<2128:SBIASH>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Chow, K. C., K. L. Chan, and A. K. H. Lau, 2002: Generation of moving spiral bands in tropical cyclones. J. Atmos. Sci., 59, 29302950, https://doi.org/10.1175/1520-0469(2002)059<2930:GOMSBI>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Corbosiero, K. L., J. Molinari, A. R. Aiyyer, and M. L. Black, 2006: The structure and evolution of Hurricane Elena (1985). Part II: Convective asymmetries and evidence for vortex Rossby waves. Mon. Wea. Rev., 134, 30733091, https://doi.org/10.1175/MWR3250.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Cotto, A., I. Gonzalez III, and H. E. Willoughby, 2015: Synthesis of vortex Rossby waves. Part I: Episodically forced waves in the inner waveguide. J. Atmos. Sci., 72, 39403957, https://doi.org/10.1175/JAS-D-15-0004.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Didlake, A. C., and R. A. Houze Jr., 2009: Convective-scale downdrafts in the principal rainband of Hurricane Katrina (2005). Mon. Wea. Rev., 137, 32693293, https://doi.org/10.1175/2009MWR2827.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Diercks, J. W., and R. A. Anthes, 1976: Diagnostic studies of spiral rainbands in a nonlinear hurricane model. J. Atmos. Sci., 33, 959975, https://doi.org/10.1175/1520-0469(1976)033<0959:DSOSRI>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Eastin, M. D., T. L. Gardner, M. C. Link, and K. C. Smith, 2012: Surface cold pools in the outer rainbands of Tropical Storm Hanna (2008) near landfall. Mon. Wea. Rev., 140, 471491, https://doi.org/10.1175/MWR-D-11-00099.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Frank, W. M., 1977: The structure and energetics of the tropical cyclone. Part I: Storm structure. Mon. Wea. Rev., 105, 11191135, https://doi.org/10.1175/1520-0493(1977)105<1119:TSAEOT>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Gall, R., J. Tuttle, and P. Hildebrand, 1998: Small-scale spiral bands observed in Hurricanes Andrew, Hugo, and Erin. Mon. Wea. Rev., 126, 17491766, https://doi.org/10.1175/1520-0493(1998)126<1749:SSSBOI>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Gonzalez, I., III, A. Cotto, and H. E. Willoughby, 2015: Synthesis of vortex Rossby waves. Part II: Vortex motion and waves in the outer waveguide. J. Atmos. Sci., 72, 39583974, https://doi.org/10.1175/JAS-D-15-0005.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Guinn, T. A., and W. H. Schubert, 1993: Hurricane spiral bands. J. Atmos. Sci., 50, 33803403, https://doi.org/10.1175/1520-0469(1993)050<3380:HSB>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hamuro, M., and Coauthors, 1969: Precipitation bands of Typhoon Vera in 1959 (part I). J. Meteor. Soc. Japan, 47, 298309, https://doi.org/10.2151/jmsj1965.47.4_298.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hence, D. A., and R. A. Houze Jr., 2008: Kinematic structure of convective-scale elements in the rainbands of Hurricanes Katrina and Rita (2005). J. Geophys. Res., 113, D15108, https://doi.org/10.1029/2007JD009429.

    • Search Google Scholar
    • Export Citation
  • Houze, R. A., Jr., 2010: Clouds in tropical cyclones. Mon. Wea. Rev., 138, 293344, https://doi.org/10.1175/2009MWR2989.1.

  • Houze, R. A., Jr., 2014: Cloud Dynamics. 2nd ed. Academic Press, 432 pp.

  • Houze, R. A., Jr., S. A. Rutledge, M. I. Biggerstaff, and B. F. Smull, 1989: Interpretation of Doppler weather radar display of midlatitude mesoscale convective systems. Bull. Amer. Meteor. Soc., 70, 608619, https://doi.org/10.1175/1520-0477(1989)070<0608:IODWRD>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Houze, R. A., Jr., and Coauthors, 2006: The Hurricane Rainband and Intensity Change Experiment: Observations and modeling of hurricanes Katrina, Ophelia, and Rita. Bull. Amer. Meteor. Soc., 87, 15031521, https://doi.org/10.1175/BAMS-87-11-1503.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Jorgensen, D. P., 1984: Mesoscale and convective-scale characteristics of mature hurricanes. Part I: General observations by research aircraft. J. Atmos. Sci., 41, 12681285, https://doi.org/10.1175/1520-0469(1984)041<1268:MACSCO>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kurihara, Y., 1976: On the development of spiral bands in a tropical cyclone. J. Atmos. Sci., 33, 940958, https://doi.org/10.1175/1520-0469(1976)033<0940:OTDOSB>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Li, Q., and Y. Wang, 2012: A comparison of inner and outer spiral rainbands in a numerically simulated tropical cyclone. Mon. Wea. Rev., 140, 27822805, https://doi.org/10.1175/MWR-D-11-00237.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Li, Q., Y. Wang, and Y. Duan, 2017: A numerical study of outer rainband formation in a sheared tropical cyclone. J. Atmos. Sci., 74, 203227, https://doi.org/10.1175/JAS-D-16-0123.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Ligda, M. G. H., 1955: Hurricane squall lines. Bull. Amer. Meteor. Soc., 36, 340342, https://doi.org/10.1175/1520-0477-36.7.340.

  • Lin, Y., Y. Li, Q. Li, M. Chen, F. Xu, Y. Wang, and B. Huang, 2018: A long-lasting vortex Rossby wave–induced rainband of Typhoon Longwang (2005). Bull. Amer. Meteor. Soc., 99, 11271134, https://doi.org/10.1175/BAMS-D-17-0122.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Macdonald, N. J., 1968: The evidence for the existence of Rossby-like waves in the hurricane vortex. Tellus, 20A, 138150, https://doi.org/10.1111/j.2153-3490.1968.tb00358.x.

    • Search Google Scholar
    • Export Citation
  • Marks, F. D., Jr., 2003: State of the science: Radar view of tropical cyclones. Radar and Atmospheric Science: A Collection of Essays in Honor of David Atlas, Meteor. Monogr., No. 52, Amer. Meteor. Soc., 33–73, https://doi.org/10.1175/0065-9401(2003)030<0033:SOTSRV>2.0.CO;2.

    • Crossref
    • Export Citation
  • Marks, F. D., Jr., and R. A. Houze Jr., 1987: Inner core structure of Hurricane Alicia from airborne Doppler radar observations. J. Atmos. Sci., 44, 12961317, https://doi.org/10.1175/1520-0469(1987)044<1296:ICSOHA>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • May, P. T., and G. J. Holland, 1999: The role of potential vorticity generation in tropical cyclone rainbands. J. Atmos. Sci., 56, 12241228, https://doi.org/10.1175/1520-0469(1999)056<1224:TROPVG>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Molinari, J., D. M. Romps, D. Vollaro, and L. Nguyen, 2012: CAPE in tropical cyclones. J. Atmos. Sci., 69, 24522463, https://doi.org/10.1175/JAS-D-11-0254.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Montgomery, M. T., and R. J. Kallenbach, 1997: A theory for vortex Rossby waves and its application to spiral bands and intensity changes in hurricanes. Quart. J. Roy. Meteor. Soc., 123, 435465, https://doi.org/10.1002/qj.49712353810.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Moon, Y., and D. S. Nolan, 2015: Spiral rainbands in a numerical simulation of Hurricane Bill (2009). Part II: Propagation of inner rainbands. J. Atmos. Sci., 72, 191215, https://doi.org/10.1175/JAS-D-14-0056.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Nolan, D. S., and J. A. Zhang, 2017: Spiral gravity waves radiating from tropical cyclones. Geophys. Res. Lett., 44, 39243931, https://doi.org/10.1002/2017GL073572.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Parsons, D. B., 1992: An explanation of intense frontal updrafts and narrow cold-frontal rainbands. J. Atmos. Sci., 49, 18101825, https://doi.org/10.1175/1520-0469(1992)049<1810:AEFIFU>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Powell, M. D., 1990a: Boundary layer structure and dynamics in outer hurricane rainbands. Part I: Mesoscale rainfall and kinematic structure. Mon. Wea. Rev., 118, 891917, https://doi.org/10.1175/1520-0493(1990)118<0891:BLSADI>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Powell, M. D., 1990b: Boundary layer structure and dynamics in outer hurricane rainbands. Part II: Downdraft modification and mixed layer recovery. Mon. Wea. Rev., 118, 918938, https://doi.org/10.1175/1520-0493(1990)118<0918:BLSADI>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Riemer, M., M. T. Montgomery, and M. E. Nicholls, 2010: A new paradigm for intensity modification of tropical cyclones: Thermodynamic impact of vertical wind shear on the inflow layer. Atmos. Chem. Phys., 10, 31633188, https://doi.org/10.5194/acp-10-3163-2010.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Rotunno, R., J. B. Klemp, and M. L. Weisman, 1988: A theory for strong, long-lived squall lines. J. Atmos. Sci., 45, 463485, https://doi.org/10.1175/1520-0469(1988)045<0463:ATFSLL>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Roux, F., J. Testud, M. Payen, and B. Pinty, 1984: West African squall-line thermodynamic structure retrieved from dual-Doppler radar observations. J. Atmos. Sci., 41, 31043121, https://doi.org/10.1175/1520-0469(1984)041<3104:WASLTS>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Rozoff, C. M., W. H. Schubert, B. D. McNoldy, and J. P. Kossin, 2006: Rapid filamentation zones in intense tropical cyclones. J. Atmos. Sci., 63, 325340, https://doi.org/10.1175/JAS3595.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Saha, S., and Coauthors, 2010: The NCEP Climate Forecast System Reanalysis. Bull. Amer. Meteor. Soc., 91, 10151057, https://doi.org/10.1175/2010BAMS3001.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Samsury, C. E., and E. J. Zipser, 1995: Secondary wind maxima in hurricanes: Airflow and relationship to rainbands. Mon. Wea. Rev., 123, 35023517, https://doi.org/10.1175/1520-0493(1995)123<3502:SWMIHA>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Sawada, M., and T. Iwasaki, 2010: Impacts of evaporation from raindrops on tropical cyclones. Part II: Features of rainbands and asymmetric structure. J. Atmos. Sci., 67, 7181, https://doi.org/10.1175/2009JAS3040.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Senn, H. V., and H. W. Hiser, 1959: On the origin of hurricane spiral rain bands. J. Meteor., 16, 419426, https://doi.org/10.1175/1520-0469(1959)016<0419:OTOOHS>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Shapiro, L. J., and H. E. Willoughby, 1982: The response of balanced hurricanes to local sources of heat and momentum. J. Atmos. Sci., 39, 378394, https://doi.org/10.1175/1520-0469(1982)039<0378:TROBHT>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Simpson, J. E., and R. E. Britter, 1980: A laboratory model of an atmospheric mesofront. Quart. J. Roy. Meteor. Soc., 106, 485500, https://doi.org/10.1002/qj.49710644907.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Skwira, G. D., J. L. Schroeder, and R. E. Peterson, 2005: Surface observations of landfalling hurricane rainbands. Mon. Wea. Rev., 133, 454465, https://doi.org/10.1175/MWR-2866.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Tang, X., W.-C. Lee, and M. Bell, 2014: A squall-line-like principal rainband in Typhoon Hagupit (2008) observed by airborne Doppler radar. J. Atmos. Sci., 71, 27332746, https://doi.org/10.1175/JAS-D-13-0307.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Tang, X., W.-C. Lee, and M. Bell, 2018: Subrainband structure and dynamic characteristics in the principal rainband of Typhoon Hagupit (2008). Mon. Wea. Rev., 146, 157173, https://doi.org/10.1175/MWR-D-17-0178.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Tompkins, A. M., 2001: Organization of tropical convection in low vertical wind shears: The role of cold pools. J. Atmos. Sci., 58, 16501672, https://doi.org/10.1175/1520-0469(2001)058<1650:OOTCIL>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Ushijima, T., 1958: Outer rain bands of typhoons. J. Meteor. Soc. Japan, 36, 110, https://doi.org/10.2151/jmsj1923.36.1_1.

  • Wakimoto, R. M., 1982: The life cycle of thunderstorm gust fronts as viewed with Doppler radar and rawinsonde data. Mon. Wea. Rev., 110, 10601082, https://doi.org/10.1175/1520-0493(1982)110<1060:TLCOTG>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wang, Y., 2002: Vortex Rossby waves in a numerically simulated tropical cyclone. Part I: Overall structure, potential vorticity, and kinetic energy budgets. J. Atmos. Sci., 59, 12131238, https://doi.org/10.1175/1520-0469(2002)059<1213:VRWIAN>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wang, Y., 2009: How do outer spiral rainbands affect tropical cyclone structure and intensity? J. Atmos. Sci., 66, 12501273, https://doi.org/10.1175/2008JAS2737.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Willoughby, H. E., 1977: Inertia-buoyancy waves in hurricanes. J. Atmos. Sci., 34, 10281039, https://doi.org/10.1175/1520-0469(1977)034<1028:IBWIH>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Willoughby, H. E., 1978: A possible mechanism for the formation of hurricane rainbands. J. Atmos. Sci., 35, 838848, https://doi.org/10.1175/1520-0469(1978)035<0838:APMFTF>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Willoughby, H. E., 1988: The dynamics of the tropical hurricane core. Aust. Meteor. Mag., 36, 183191.

  • Willoughby, H. E., 1990: Temporal changes of the primary circulation in tropical cyclones. J. Atmos. Sci., 47, 242264, https://doi.org/10.1175/1520-0469(1990)047<0242:TCOTPC>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Willoughby, H. E., J. A. Clos, and M. G. Shoreibah, 1982: Concentric eye walls, secondary wind maxima, and the evolution of the hurricane vortex. J. Atmos. Sci., 39, 395411, https://doi.org/10.1175/1520-0469(1982)039<0395:CEWSWM>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Willoughby, H. E., F. D. Marks Jr., and R. J. Feinberg, 1984: Stationary and moving convective bands in hurricanes. J. Atmos. Sci., 41, 31893211, https://doi.org/10.1175/1520-0469(1984)041<3189:SAMCBI>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wu, C.-C., K. K. W. Cheung, and Y.-Y. Lo, 2009: Numerical study of the rainfall event due to the interaction of Typhoon Babs (1998) and the northeasterly monsoon. Mon. Wea. Rev., 137, 20492064, https://doi.org/10.1175/2009MWR2757.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Yu, C.-K., and C.-L. Tsai, 2010: Surface pressure features of landfalling typhoon rainbands and their possible causes. J. Atmos. Sci., 67, 28932911, https://doi.org/10.1175/2010JAS3312.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Yu, C.-K., and Y. Chen, 2011: Surface fluctuations associated with tropical cyclone rainbands observed near Taiwan during 2000–08. J. Atmos. Sci., 68, 15681585, https://doi.org/10.1175/2011JAS3725.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Yu, C.-K., and C.-L. Tsai, 2013: Structural and surface features of arc-shaped radar echoes along an outer tropical cyclone rainband. J. Atmos. Sci., 70, 5672, https://doi.org/10.1175/JAS-D-12-090.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Yu, C.-K., and C.-L. Tsai, 2017: Structural changes of an outer tropical cyclone rainband encountering the topography of northern Taiwan. Quart. J. Roy. Meteor. Soc., 143, 11071122, https://doi.org/10.1002/qj.2994.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Yu, C.-K., C.-Y. Lin, L.-W. Cheng, J.-S. Luo, C.-C. Wu, and Y. Chen, 2018: The degree of prevalence of similarity between outer tropical cyclone rainbands and squall lines. Sci. Rep., 8, 8247, https://doi.org/10.1038/s41598-018-26553-8.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Zipser, E. J., 1977: Mesoscale and convective-scale downdrafts as distinct components of squall-line structure. Mon. Wea. Rev., 105, 15681589, https://doi.org/10.1175/1520-0493(1977)105<1568:MACDAD>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 421 173 9
PDF Downloads 321 162 8

Tracking a Long-Lasting Outer Tropical Cyclone Rainband: Origin and Convective Transformation

View More View Less
  • 1 Department of Atmospheric Sciences, National Taiwan University, Taipei, Taiwan
Restricted access

Abstract

This study used radar and surface observations to track a long-lasting outer tropical cyclone rainband (TCR) of Typhoon Jangmi (2008) over a considerable period of time (~10 h) from its formative to mature stage. Detailed analyses of these unique observations indicate that the TCR was initiated on the eastern side of the typhoon at a radial distance of ~190 km as it detached from the upwind segment of a stratiform rainband located close to the inner-core boundary. The outer rainband, as it propagated cyclonically outward, underwent a prominent convective transformation from generally stratiform precipitation during the earlier period to highly organized, convective precipitation during its mature stage. The transformation was accompanied by a clear trend of surface kinematics and thermodynamics toward squall-line-like features. The observed intensification of the rainband was not simply related to the spatial variation of the ambient CAPE or potential instability; instead, the dynamical interaction between the prerainband vertical shear and cold pools, with progression toward increasingly optimal conditions over time, provides a reasonable explanation for the temporal alternation of the precipitation intensity. The increasing intensity of cold pools was suggested to play an essential role in the convective transformation for the rainband. The propagation characteristics of the studied TCR were distinctly different from those of wave disturbances frequently documented within the cores of tropical cyclones; however, they were consistent with the theoretically predicted propagation of convectively generated cold pools. The convective transformation, as documented in the present case, is anticipated to be one of the fundamental processes determining the evolving and structural nature of outer TCRs.

© 2019 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).

Corresponding author: Cheng-Ku Yu, yuku@ntu.edu.tw

Abstract

This study used radar and surface observations to track a long-lasting outer tropical cyclone rainband (TCR) of Typhoon Jangmi (2008) over a considerable period of time (~10 h) from its formative to mature stage. Detailed analyses of these unique observations indicate that the TCR was initiated on the eastern side of the typhoon at a radial distance of ~190 km as it detached from the upwind segment of a stratiform rainband located close to the inner-core boundary. The outer rainband, as it propagated cyclonically outward, underwent a prominent convective transformation from generally stratiform precipitation during the earlier period to highly organized, convective precipitation during its mature stage. The transformation was accompanied by a clear trend of surface kinematics and thermodynamics toward squall-line-like features. The observed intensification of the rainband was not simply related to the spatial variation of the ambient CAPE or potential instability; instead, the dynamical interaction between the prerainband vertical shear and cold pools, with progression toward increasingly optimal conditions over time, provides a reasonable explanation for the temporal alternation of the precipitation intensity. The increasing intensity of cold pools was suggested to play an essential role in the convective transformation for the rainband. The propagation characteristics of the studied TCR were distinctly different from those of wave disturbances frequently documented within the cores of tropical cyclones; however, they were consistent with the theoretically predicted propagation of convectively generated cold pools. The convective transformation, as documented in the present case, is anticipated to be one of the fundamental processes determining the evolving and structural nature of outer TCRs.

© 2019 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).

Corresponding author: Cheng-Ku Yu, yuku@ntu.edu.tw
Save