Editorial Type:
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Article Type:
Research Article

Vertical Motions in Precipitation Bands in Three Winter Cyclones

Marcia Cronce Department of Atmospheric Sciences, University of Illinois at Urbana–Champaign, Urbana, Illinois

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Robert M. Rauber Department of Atmospheric Sciences, University of Illinois at Urbana–Champaign, Urbana, Illinois

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Kevin R. Knupp Atmospheric Sciences Department, University of Alabama in Huntsville, Huntsville, Alabama

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Brian F. Jewett Department of Atmospheric Sciences, University of Illinois at Urbana–Champaign, Urbana, Illinois

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Justin T. Walters Atmospheric Sciences Department, University of Alabama in Huntsville, Huntsville, Alabama

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Dustin Phillips Atmospheric Sciences Department, University of Alabama in Huntsville, Huntsville, Alabama

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Print Publication:
01 Oct 2007
DOI:
https://doi.org/10.1175/JAM2533.1
Page(s):
1523–1543
Restricted access

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Abstract

The University of Alabama in Huntsville Mobile Integrated Profiling System 915-MHz profiler was deployed in January and February of 2004 to measure vertical air velocities in finescale precipitation bands in winter cyclones. The profiler was placed to sample the “wraparound” quadrant of three winter cyclones in the central and southern United States, and it obtained high-resolution measurements of the vertical structure of a series of bands in each storm. The data revealed bands that were up to 6 km deep, 10–50 km wide, and spaced about 5–20 km apart. Measurements of vertical air motion w within these bands were retrieved from the Doppler spectra using the lower-bound method, adapted to account for the effects of spectral broadening caused by the horizontal wind, wind shear, and turbulence. Derived vertical air motions ranged from −4.3 to 6.7 m s−1, with an uncertainty of about ±0.6 m s−1. Approximately 29% of the 1515 total derived values were negative, 35% exceeded 1 m s−1, and 9% exceeded 2.0 m s−1. These values are consistent with studies in the Pacific Northwest, except that more extreme values were observed in one band than have been previously reported. There was a high correlation between values of signal-to-noise ratio (SNR) and w within each band (0.60 ≤ r ≤ 0.85), in the composite of bands from each cyclone (0.59 ≤ r ≤ 0.79), and in the overall analysis (r = 0.68). The strongest updrafts were typically between 2.0 and 4.0 m s−1 and were located near the center of each band in regions of high SNR. Regions of downdrafts within the bands had maximum values between −1.0 and −4.3 m s−1 and were typically located along the edges of the bands in regions of low SNR. These results are consistent with snow growth and sublimation processes. The magnitudes of the vertical velocities in the core of the bands were comparable to theoretical predictions for moist symmetric instability (MSI) under inviscid conditions but would appear to be somewhat larger than expected for MSI when turbulent mixing is considered, suggesting that other instabilities, such as potential instability, may have contributed to the band development in these storms.

Corresponding author address: Robert M. Rauber, Department of Atmospheric Sciences, University of Illinois, 105 S. Gregory St., Urbana, IL 61801. Email: r-rauber@uiuc.edu

Abstract

The University of Alabama in Huntsville Mobile Integrated Profiling System 915-MHz profiler was deployed in January and February of 2004 to measure vertical air velocities in finescale precipitation bands in winter cyclones. The profiler was placed to sample the “wraparound” quadrant of three winter cyclones in the central and southern United States, and it obtained high-resolution measurements of the vertical structure of a series of bands in each storm. The data revealed bands that were up to 6 km deep, 10–50 km wide, and spaced about 5–20 km apart. Measurements of vertical air motion w within these bands were retrieved from the Doppler spectra using the lower-bound method, adapted to account for the effects of spectral broadening caused by the horizontal wind, wind shear, and turbulence. Derived vertical air motions ranged from −4.3 to 6.7 m s−1, with an uncertainty of about ±0.6 m s−1. Approximately 29% of the 1515 total derived values were negative, 35% exceeded 1 m s−1, and 9% exceeded 2.0 m s−1. These values are consistent with studies in the Pacific Northwest, except that more extreme values were observed in one band than have been previously reported. There was a high correlation between values of signal-to-noise ratio (SNR) and w within each band (0.60 ≤ r ≤ 0.85), in the composite of bands from each cyclone (0.59 ≤ r ≤ 0.79), and in the overall analysis (r = 0.68). The strongest updrafts were typically between 2.0 and 4.0 m s−1 and were located near the center of each band in regions of high SNR. Regions of downdrafts within the bands had maximum values between −1.0 and −4.3 m s−1 and were typically located along the edges of the bands in regions of low SNR. These results are consistent with snow growth and sublimation processes. The magnitudes of the vertical velocities in the core of the bands were comparable to theoretical predictions for moist symmetric instability (MSI) under inviscid conditions but would appear to be somewhat larger than expected for MSI when turbulent mixing is considered, suggesting that other instabilities, such as potential instability, may have contributed to the band development in these storms.

Corresponding author address: Robert M. Rauber, Department of Atmospheric Sciences, University of Illinois, 105 S. Gregory St., Urbana, IL 61801. Email: r-rauber@uiuc.edu

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Journal of Applied Meteorology and Climatology

  • Atlas, D., 1964: Advances in radar meteorology. Advances in Geophysics, Vol. 10, Academic Press, 318–478.

  • Atlas, D., R. C. Srivastava, and R. S. Sekhon, 1973: Doppler radar characteristics of precipitation at vertical incidence. Rev. Geophys. Space Phys., 11 , 1–35.

    • Search Google Scholar
    • Export Citation

  • Battan, L. J., 1973: Turbulence spreading of Doppler spectrum. J. Appl. Meteor., 12 , 822–824.

  • Battan, L. S., and J. B. Theiss, 1966: Observations of vertical motions and particle sizes in a thunderstorm. J. Atmos. Sci., 23 , 78–87.

    • Search Google Scholar
    • Export Citation

  • Bennetts, D. A., and B. J. Hoskins, 1979: Conditional symmetric instability—A possible explanation for frontal rainbands. Quart. J. Roy. Meteor. Soc., 105 , 945–962.

    • Search Google Scholar
    • Export Citation

  • Bennetts, D. A., and J. C. Sharp, 1982: The relevance of conditional symmetric instability to the prediction of mesoscale frontal rainbands. Quart. J. Roy. Meteor. Soc., 108 , 595–602.

    • Search Google Scholar
    • Export Citation

  • Bluestein, H. B., 1993: Synoptic-Dynamic Meteorology in Midlatitudes. Vol. 2, Observations and Theory of Weather Systems, Oxford University Press, 594 pp.

    • Search Google Scholar
    • Export Citation

  • Blyth, A. M., W. A. Cooper, and J. B. Jensen, 1988: A study of the source of entrained air in Montana cumuli. J. Atmos. Sci., 45 , 3944–3964.

    • Search Google Scholar
    • Export Citation

  • Chadwick, R. B., and K. P. Moran, 1980: Long-term measurements of C2 n in the boundary layer. Radio Sci., 15 , 355–362.

  • Donaldson Jr., R. J., and R. Wexler, 1969: Flight hazards in thunderstorms determined by Doppler velocity variance. J. Appl. Meteor., 8 , 128–133.

    • Search Google Scholar
    • Export Citation

  • Emanuel, K. A., 1983: The Lagrangian parcel dynamics of moist symmetric instability. J. Atmos. Sci., 40 , 2368–2376.

  • Foote, G. B., and P. S. du Toit, 1969: Terminal velocity of raindrops aloft. J. Appl. Meteor., 8 , 249–253.

  • Geerts, B., and P. V. Hobbs, 1991: Organization and structure of clouds and precipitation on the mid-Atlantic coast of the United States. Part IV: Retrieval of the thermodynamic and cloud microphysical structures of a frontal rainband from Doppler radar data. J. Atmos. Sci., 48 , 1287–1305.

    • Search Google Scholar
    • Export Citation

  • Gossard, E. E., R. G. Strauch, D. C. Welsh, and S. Y. Matrosov, 1992: Cloud layers, particle identification, and rain-rate profiles from ZRVf measurements by clear-air Doppler radars. J. Atmos. Oceanic Technol., 9 , 108–119.

    • Search Google Scholar
    • Export Citation

  • Hertzman, O., and P. V. Hobbs, 1988: The mesoscale and microscale structure and organization of clouds and precipitation in midlatitude cyclones. Part XIV: Three-dimensional airflow and vorticity budget of rainbands in a warm occlusion. J. Atmos. Sci., 45 , 893–914.

    • Search Google Scholar
    • Export Citation

  • Hertzman, O., P. V. Hobbs, and J. D. Locatelli, 1988: The mesoscale and microscale structure and organization of clouds and precipitation in midlatitude cyclones. Part XVI: Three dimensional airflow and vertical vorticity budget for a warm front. J. Atmos. Sci., 45 , 3650–3666.

    • Search Google Scholar
    • Export Citation

  • Herzegh, P. H., and P. V. Hobbs, 1980: The mesoscale and microscale structure and organization of clouds and precipitation in midlatitude cyclones. II: Warm-frontal clouds. J. Atmos. Sci., 37 , 597–611.

    • Search Google Scholar
    • Export Citation

  • Herzegh, P. H., and P. V. Hobbs, 1981: The mesoscale and microscale structure and organization of clouds and precipitation in midlatitude cyclones. IV: Vertical air motions and microphysical structures of prefrontal surge clouds and cold-frontal clouds. J. Atmos. Sci., 38 , 1771–1784.

    • Search Google Scholar
    • Export Citation

  • Hobbs, P. V., T. J. Matejka, P. H. Herzegh, J. D. Locatelli, and R. A. Houze Jr., 1980: The mesoscale and microscale structure and organization of clouds and precipitation in midlatitude cyclones. I: A case study of a cold front. J. Atmos. Sci., 37 , 568–596.

    • Search Google Scholar
    • Export Citation

  • Houze Jr., R. A., S. A. Rutledge, T. J. Matejka, and P. V. Hobbs, 1981: The mesoscale and microscale structure and organization of clouds and precipitation in midlatitude cyclones. III: Air motions and precipitation growth in a warm-frontal rainband. J. Atmos. Sci., 38 , 639–649.

    • Search Google Scholar
    • Export Citation

  • Innocentini, V., and E. dos Santos Caetano Neto, 1992: A numerical study of the role of humidity in the updraft driven by moist slantwise convection. J. Atmos. Sci., 49 , 1092–1106.

    • Search Google Scholar
    • Export Citation

  • Knight, D. J., and P. V. Hobbs, 1988: The mesoscale and microscale structure and organization of clouds and precipitation in midlatitude cyclones. Part XV: A numerical modeling study of frontogenesis and cold-frontal rainbands. J. Atmos. Sci., 45 , 915–930.

    • Search Google Scholar
    • Export Citation

  • Knupp, K. R., and W. R. Cotton, 1985: Convective cloud downdraft structure—An interpretive survey. Rev. Geophys., 23 , 183–215.

  • Locatelli, J. D., and P. V. Hobbs, 1974: Fallspeeds and masses of solid precipitation particles. J. Geophys. Res., 79 , 2185–2197.

  • Locatelli, J. D., and P. V. Hobbs, 1987: The mesoscale and microscale structure and organization of clouds and precipitation in midlatitude cyclones. XIII: Structure of a warm front. J. Atmos. Sci., 44 , 2290–2309.

    • Search Google Scholar
    • Export Citation

  • Martin, J. E., 1998: The structure and evolution of a continental winter cyclone. Part II: Frontal forcing of an extreme snow event. Mon. Wea. Rev., 126 , 329–348.

    • Search Google Scholar
    • Export Citation

  • Nicosia, D. J., and R. H. Grumm, 1999: Mesoscale band formation in three major northeastern United States snowstorms. Wea. Forecasting, 14 , 346–368.

    • Search Google Scholar
    • Export Citation

  • Novak, D. R., L. F. Bosart, D. Keyser, and J. S. Waldstreicher, 2004: An observational study of cold season–banded precipitation in the northeast U.S. cyclones. Wea. Forecasting, 19 , 993–1010.

    • Search Google Scholar
    • Export Citation

  • Passarelli Jr., R. E., 1978: Theoretical and observational study of snow-size spectra and snowflake aggregation efficiencies. J. Atmos. Sci., 35 , 882–889.

    • Search Google Scholar
    • Export Citation

  • Persson, P. O. G., and T. T. Warner, 1995: The nonlinear evolution of idealized, unforced, conditional symmetric instability: A numerical study. J. Atmos. Sci., 52 , 3449–3474.

    • Search Google Scholar
    • Export Citation

  • Probert-Jones, J. R., and W. G. Harper, 1961: Vertical air motions in showers as revealed by Doppler radar. Proc. Ninth Weather Radar Conf., Boston, MA, Amer. Meteor. Soc., 225–232.

  • Ralph, F. M., 1995: Using radar-measured radial vertical velocities to distinguish precipitation scattering from clear-air scattering. J. Atmos. Oceanic Technol., 12 , 257–267.

    • Search Google Scholar
    • Export Citation

  • Rauber, R. M., M. K. Ramamurthy, and A. Tokay, 1994: Synoptic and mesoscale structure of a severe freezing rain event: The St. Valentine’s Day ice storm. Wea. Forecasting, 9 , 183–208.

    • Search Google Scholar
    • Export Citation

  • Reuter, G. W., and M. K. Yau, 1990: Observations of slantwise convective instability in winter cyclones. Mon. Wea. Rev., 118 , 447–458.

    • Search Google Scholar
    • Export Citation

  • Rogers, R. R., S. G. Leblanc, S. A. Cohn, W. L. Ecklund, D. A. Carter, and J. S. Wilson, 1996: Profiler measurements of turbulence and wind shear in a snowstorm. Beitr. Phys. Freien Atmos., 69 , 27–36.

    • Search Google Scholar
    • Export Citation

  • Sanders, F., 1986: Frontogenesis and symmetric stability in a major New England snowstorm. Mon. Wea. Rev., 114 , 1847–1862.

  • Sanders, F., and L. F. Bosart, 1985: Mesoscale structure in the Megalopolitan snowstorm, 11–12 February 1983. Part II: Doppler radar study of the New England snowband. J. Atmos. Sci., 42 , 1398–1407.

    • Search Google Scholar
    • Export Citation

  • Schultz, D. M., and P. N. Schumacher, 1999: The use and misuse of conditional symmetric instability. Mon. Wea. Rev., 127 , 2709–2732.

  • Seltzer, M. A., R. E. Passarelli, and K. A. Emanuel, 1985: The possible role of symmetric instability in the formation of precipitation bands. J. Atmos. Sci., 42 , 2207–2219.

    • Search Google Scholar
    • Export Citation

  • Sienkiewicz, J. M., J. D. Locatelli, P. V. Hobbs, and B. Geerts, 1989: Organization and structure of clouds and precipitation on the mid-Atlantic coast of the United States. Part II: The mesoscale and microscale structures of some frontal rainbands. J. Atmos. Sci., 46 , 1349–1364.

    • Search Google Scholar
    • Export Citation

  • Thorpe, A. J., and K. A. Emanuel, 1985: Frontogenesis in the presence of small stability to slantwise convection. J. Atmos. Sci., 42 , 1809–1824.

    • Search Google Scholar
    • Export Citation

  • Wang, P-Y., and P. V. Hobbs, 1983: The mesoscale and microscale structure and organization of clouds and precipitation in midlatitude cyclones. X: Wavelike rainbands in an occlusion. J. Atmos. Sci., 40 , 1950–1964.

    • Search Google Scholar
    • Export Citation

  • Wang, P-Y., D. B. Parsons, and P. V. Hobbs, 1983: The mesoscale and microscale structure and organization of clouds and precipitation in midlatitude cyclones. VI: Wavelike rainbands associated with a cold-frontal zone. J. Atmos. Sci., 40 , 543–558.

    • Search Google Scholar
    • Export Citation

  • Williams, C. R., W. L. Ecklund, and K. S. Gage, 1995: Classification of precipitating clouds in the Tropics using 915-MHz wind profilers. J. Atmos. Oceanic Technol., 12 , 996–1012.

    • Search Google Scholar
    • Export Citation

  • Williams, C. R., W. L. Ecklund, P. E. Johnston, and K. S. Gage, 2000: Cluster analysis techniques to separate air motion and hydrometers in vertical incident profiler observations. J. Atmos. Oceanic Technol., 17 , 949–962.

    • Search Google Scholar
    • Export Citation

  • Wolfsberg, D. G., K. A. Emanuel, and R. E. Passarelli, 1986: Band formation in a New England winter storm. Mon. Wea. Rev., 114 , 1552–1569.

    • Search Google Scholar
    • Export Citation

  • Xu, Q., 1992: Formation and evolution of frontal rainbands and geostrophic potential vorticity anomalies. J. Atmos. Sci., 49 , 629–648.

    • Search Google Scholar
    • Export Citation

  • Zhang, D-L., and H-R. Cho, 1995: Three-dimensional simulation of frontal rainbands and conditional symmetric instability in the Eady-wave model. Tellus, 47A , 45–61.

    • Search Google Scholar
    • Export Citation
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