• Abbe, C. A., Jr., 1915: Gigantic snowflakes. Mon. Wea. Rev.,43, 73.

  • Anthes, R. A., 1990: Recent applications of the Penn State/NCAR mesoscale model to synoptic, mesoscale and climate studies. Bull. Amer. Meteor. Soc.,71, 1610–1629.

  • ——, and T. T. Warner, 1978: Development of hydrodynamic models suitable for air pollution and other mesometeorological studies. Mon. Wea. Rev.,106, 1045–1078.

  • Auer, A. H., Jr., 1971: Some large snowflakes. Weather,26, 121–122.

  • Baumgardner, D., and A. Rodi, 1989: Laboratory and wind tunnel evaluation of the Rosemount Icing Detector. J. Atmos. Oceanic Technol.,6, 971–979.

  • Cober, S. G., G. A. Isaac, and J. W. Strapp, 1995: Aircraft icing measurements in East Coast winter storms. J. Appl. Meteor.,34, 88–100.

  • Cooper, W. A., and R. P. Lawson, 1984: Physical interpretation of results from the HIPLEX-1 Experiment. J. Appl. Meteor.,23, 523–540.

  • Corliss, W. R., 1984: Tornadoes, Dark Days, Anomalous Precipitation, and Related Weather Phenomena. Sourcebook Project, 196 pp.

  • Denning, W. F., 1912: Large snowflakes. Symon’s Meteor. Mag.,47, 22.

  • Diamond, M., and W. P. Lowry, 1954: Correlation of density of new snow with 700-millibar temperature. J. Meteor.,11, 512–513.

  • Dobrowolski, A. B., 1903: La Neige et le Givre. Vol. 3, Rapports Scientifiques, Resultats du Voyagede S. Y. Belgica, 1897–1899, J. E. Buschman, 78 pp.

  • Dudhia, J., 1993: A nonhydrostatic version of the Penn State/NCAR mesoscale model: Validation tests and simulation of an Atlantic cyclone and cold front. Mon. Wea. Rev.,121, 1493–1513.

  • Furukawa, Y., M. Yamamoto, and T. Kuroda, 1987: Ellipsometric study of the transition layer on the surface of an ice crystal. J. Cryst. Growth,82, 665–677.

  • Grell, G. A., 1993: Prognostic evaluation of assumptions used by cumulus parameterizations. Mon. Wea. Rev.,121, 764–787.

  • ——, J. Dudhia, and D. R. Stauffer, 1994: A description of the fifth-generation Penn State/NCAR Mesoscale Model (MM5). NCAR Mesoscale and Microscale Meteorology Division Tech. Note NCAR/TM398+STR, 138 pp.

  • Gunn, K. L. S., and J. S. Marshall, 1958: The distribution with size of aggregate snowflakes. J. Meteor.,15, 452–461.

  • Hawke, E. L., 1951: Outsize snowflakes. Weather,6, 254.

  • 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.

  • Heymsfield, A. J., 1986: Ice particle evolution in the anvil of a severe thunderstorm during CCOPE. J. Atmos. Sci.,43, 2463–2478.

  • ——, and L. M. Miloshevich, 1989: Evaluation of liquid water measuring instruments in cold clouds sampled during FIRE. J. Atmos. Oceanic Technol.,6, 378–388.

  • Hobbs, P. V., and J. D. Locatelli, 1978: Rainbands, precipitation cores and generating cells in a cyclonic storm. J. Atmos. Sci.,35, 230–241.

  • ——, and Coauthors, 1971: Contributions from the Cloud Physics Group. Res. Rep. VI: Studies of winter cyclonic storms over the Cascade Mountains, 1970–1971. 305 pp. [Available from Tech. Rep., Department of Atmospheric Sciences, University of Washington, Seattle, WA, 98195.].

  • ——, H. Harrison, and E. Robinson, 1974: Atmospheric effects of pollutants. Science,183, 909–915.

  • Holroyd, E. W., III, 1971: The meso- and micro-scale structure of Great Lakes snowstorm bands—a synthesis of ground measurements, radar data, and satellite observations. Ph.D. dissertation, College of Arts and Sciences, State University of New York at Albany, 148 pp.

  • Isaac, G. A., 1991: Microphysical characteristics of Canadian Atlantic storms. Atmos. Res.,26, 339–360.

  • Jiusto, J. E., 1971: Crystal development and glaciation of a super-cooled cloud. J. Rech. Atmos.,5, 69–85.

  • King, W. D., D. A. Parkin, and R. J. Handsworth, 1978: A hot wire liquid water device having fully calculable response characteristics. J. Appl. Meteor.,17, 1809–1813.

  • Knollenberg, R. G., 1970: The optical array: An alternative to scattering or extinction for airborne particle size determination. J. Appl. Meteor.,9, 86–103.

  • ——, 1981: Techniques for probing cloud microstructure. Clouds, Their Formation Optical Properties and Effects, P. V. Hobbs and A. Deepak, Eds., Academic Press, 15–92.

  • Lawson, R. P., R. E. Stewart, J. W. Strapp, and G. A. Isaac, 1993a: Airborne measurements of the origin and growth of very large snowflakes. Geophys. Res. Lett.,20, 53–56.

  • ——, R. H. Cormack, and K. A. Weaver, 1993b: A new airborne precipitation spectrometer for atmospheric research. Preprints, Eighth Symp. Meteorological Observations and Instrumentation, Anaheim, CA, Amer. Meteor. Soc., 30–35.

  • Lo, K. K., 1983: Growth processes of snow. Ph.D. thesis, Massachusetts Institute of Technology, 192 pp.

  • ——, and R. E. Passarelli, Jr., 1981: Height evolution of snow-size distributions. Preprints, 20th Conf. on Radar Meteorology, Boston, MA, Amer. Meteor. Soc., 397–401.

  • ——, and ——, 1982: The growth of snow in winter storms: An airborne observational study. J. Atmos. Sci.,39, 697–706.

  • Lowe, E. J., 1887: Snowstorm of January 7, 1887. Nature,35, 271.

  • Magono, C., 1953: On the growth of snowflake and graupel. Sci. Rep., Yokohama Natl. Univ.,1, 18–40.

  • ——, 1960: Structure of snowfall revealed by geographic distribution of snow crystals. Physics of Precipitation, Geophys. Monogr., No. 5, Amer. Geophys. Union, 142–161.

  • ——, and T. Nakamura, 1965: Aerodynamic studies of falling snowflakes. J. Meteor. Soc. Japan,43, 139–147.

  • ——, and C. W. Lee, 1966: Meteorological classification of natural snow crystals. J. Fac. Sci., Hokkaido Imp. Univer., Ser. VII, 2, 321–362.

  • Mitchell, D. L., 1988: Evolution of snow-size spectra in cyclonic storms. Part I: Snow growth by vapor deposition and aggregation. J. Atmos. Sci.,45, 3431–3451.

  • ——, 1990: Evolution of snow-size spectra predicted by the growth processes of diffusion, aggregation and riming. Preprints, Conf. on Cloud Physics, San Francisco, CA, Amer. Meteor. Soc., 270–277.

  • ——, 1991: Evolution of snow-size spectra in cyclonic storms. Part II: Deviations from the exponential form. J. Atmos. Sci.,48, 1885–1899.

  • ——, 1994: A model predicting the evolution of ice particle size spectra and radiative properties of cirrus clouds. Part I: Microphysics. J. Atmos. Sci.,51, 797–816.

  • ——, 1995: An analytical model predicting the evolution of ice particle size distributions. Ph.D. dissertation, University of Nevada at Reno, 171 pp.

  • Pike, W. S., 1988: Unusually-large snowflakes. J. Meteor.,13, 3–16.

  • Plunket, J. D., 1891: Snowfalls. Mon. Wea. Rev.,19, 11.

  • Power, B. A., 1962: Relationship between density of newly fallen snow and form of snow crystals. Nature,193, 1171.

  • Pruppacher, H. R., and J. D. Klett, 1978: Microphysics of Clouds and Precipitation. D. Reidel, 707 pp.

  • Rauber, R. M., 1987: Characterization of cloud ice and precipitation during wintertime over the mountains of northern Colorado. J. Appl. Meteorol.,26, 488–524.

  • ——, 1985: Physical structure of northern Colorado river basin cloud systems. Ph.D. dissertation, Colorado State University, Ft. Collins, CO, 362 pp.

  • Rogers, D. C., 1973: The aggregation of natural ice crystals. M.S. thesis, Dept. of Atmospheric Resources, University of Wyoming, 91 pp.

  • Schols, J. L., J. A. Weinman, G. D. Alexander, R. E. Stewart, L. J. Angus, and A. C. L. Lee, 1998: Microwave properties of frozen precipitation around a North Atlantic cyclone. J. Appl. Meteorol., in press.

  • Stewart, R. E., 1984: Deep 0°C isothermal layers within precipitation bands over southern Ontario. J. Geophys. Res.,89, 2567–2572.

  • ——, 1991: Canadian Atlantic Storms Program: Progress and plans of the meteorological component. Bull. Amer. Meteor. Soc.,72, 364–371.

  • ——, 1992: Precipitation types in the transition region of winter storms. Bull. Amer. Meteor. Soc.,73, 287–296.

  • ——, and R. W. Crawford, 1995: Some characteristics of the precipitation formed within winter storms over eastern Newfoundland. Atmos. Res.,36, 17–37.

  • ——, J. D. Marwitz, J. C. Pace, and R. E. Carbone, 1984: Characteristics through the melting layers of stratiform clouds. J. Atmos. Sci.,41, 3227–3237.

  • ——, R. W. Shaw, and G. A. Isaac, 1987: Canadian Atlantic Storms Program: The Meteorological Field Project. Bull. Amer. Meteor. Soc.,68, 338–345.

  • ——, R. W. Crawford, and N. R. Donaldson, 1990: Precipitation characteristics within several Canadian East Coast winter storms. Atmos. Res.,25, 293–316.

  • Szeto, K. K., and R. E. Stewart, 1997: Effects of melting on frontogenesis. J. Atmos. Sci.,54, 689–702.

  • ——, C. A. Lin, and R. E. Stewart, 1988a: Mesoscale circulations forced by melting snow. Part I. Basic simulations and dynamics. J. Atmos. Sci.,45, 1629–1641.

  • ——, R. E. Stewart, and C. A. Lin, 1988b: Mesoscale circulations forced by melting snow. Part II. Application to meteorological features. J. Atmos. Sci.,45, 1642–1650.

  • Thomson, A. D., and R. List, 1996: Raindrop spectra and updraft determination by combining Doppler radar and distrometer. J. Atmos. Oceanic Technol.,13, 465–476.

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Observations and Numerical Simulations of the Origin and Development of Very Large Snowflakes

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  • 1 SPEC, Inc., Boulder, Colorado
  • | 2 Climate Processes and Earth Observation Division, Atmospheric Environment Service, Downsview, Ontario, Canada
  • | 3 SPEC, Inc., Boulder, Colorado
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Abstract

The Canadian Atlantic Storms Program (CASP II) field experiment was conducted near St. John’s, Newfoundland, Canada, during January–March 1992, and it focused on the nature of winter storms. Analyses of CASP II aircraft, surface, satellite, and radar observations collected during an intensive study of the origin and development of 9 mm h−1 precipitation containing 4–5-cm diameter snowflakes are compared in this article with results of the MM5 (mesoscale) and Mitchell (microphysical) models. MM5 simulations of the thermal, kinematic, and bulk microphysical fields were in good agreement with the observations; this comparison provided the basis for extending the spatial and temporal scales of the aircraft observations to a larger-scale domain using the model results. The Mitchell analytical–numerical model was used to improve the understanding of the microphysical processes that led to the development of the very large snowflakes. A synthesis of results using the different techniques leads to the conclusion that the snowflakes originated as 3–5-mm dendritic crystals in an area of weak convective instability at 5 km and were transported downwind in a strongly sheared airflow. The dendrites aggregated, fell into an existing snowzone (supported in some regions by vertical motion with velocities ranging from 0.2–0.6 m s−1), and continued to descend along a deep, downward sloping layer with temperatures near 0°C. Rapid aggregation occurred in the near 0°C region in particular and without appreciable particle breakup. An exponential fit to the particle size distribution in the region of very large snowflakes had a slope parameter on the order of 100 m−1.

* Current affiliation: National Oceanic and Atmospheric Administration, Boulder, Colorado.

Corresponding author address: Dr. R. Paul Lawson, SPEC, Inc., 5401 Western, Boulder, CO 80301.

Email: plawson@specinc.com

Abstract

The Canadian Atlantic Storms Program (CASP II) field experiment was conducted near St. John’s, Newfoundland, Canada, during January–March 1992, and it focused on the nature of winter storms. Analyses of CASP II aircraft, surface, satellite, and radar observations collected during an intensive study of the origin and development of 9 mm h−1 precipitation containing 4–5-cm diameter snowflakes are compared in this article with results of the MM5 (mesoscale) and Mitchell (microphysical) models. MM5 simulations of the thermal, kinematic, and bulk microphysical fields were in good agreement with the observations; this comparison provided the basis for extending the spatial and temporal scales of the aircraft observations to a larger-scale domain using the model results. The Mitchell analytical–numerical model was used to improve the understanding of the microphysical processes that led to the development of the very large snowflakes. A synthesis of results using the different techniques leads to the conclusion that the snowflakes originated as 3–5-mm dendritic crystals in an area of weak convective instability at 5 km and were transported downwind in a strongly sheared airflow. The dendrites aggregated, fell into an existing snowzone (supported in some regions by vertical motion with velocities ranging from 0.2–0.6 m s−1), and continued to descend along a deep, downward sloping layer with temperatures near 0°C. Rapid aggregation occurred in the near 0°C region in particular and without appreciable particle breakup. An exponential fit to the particle size distribution in the region of very large snowflakes had a slope parameter on the order of 100 m−1.

* Current affiliation: National Oceanic and Atmospheric Administration, Boulder, Colorado.

Corresponding author address: Dr. R. Paul Lawson, SPEC, Inc., 5401 Western, Boulder, CO 80301.

Email: plawson@specinc.com

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