• Anderson, N. F., , C. A. Grainger, , and J. L. Stith, 2005: Characteristics of strong updrafts in precipitation systems over the central tropical Pacific Ocean and in the Amazon. J. Appl. Meteor., 44, 731738, doi:10.1175/JAM2231.1.

    • Search Google Scholar
    • Export Citation
  • Arakawa, A., 2004: The cumulus parameterization problem: Past, present, and future. J. Climate, 17, 24932525, doi:10.1175/1520-0442(2004)017<2493:RATCPP>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Byers, H. R., , and R. R. Braham, 1949: The thunderstorm. U.S. Weather Bureau Thunderstorm Project Rep., 287 pp.

  • Carter, D. A., , K. S. Gage, , W. L. Ecklund, , W. M. Angevine, , P. E. Johnston, , A. C. Riddle, , J. Wilson, , and C. R. Williams, 1995: Developments in UHF lower tropospheric wind profiling at NOAA’s Aeronomy Laboratory. Radio Sci., 30, 9771001, doi:10.1029/95RS00649.

    • Search Google Scholar
    • Export Citation
  • Casey, S. P. F., , E. J. Fetzer, , and B. H. Kahn, 2012: Revised identification of tropical oceanic cumulus congestus as viewed by CloudSat. Atmos. Chem. Phys., 12, 15871595, doi:10.5194/acp-12-1587-2012.

    • Search Google Scholar
    • Export Citation
  • Cifelli, R., , and S. A. Rutledge, 1994: Vertical motion structure in Maritime Continent mesoscale convective systems: Results from a 50-MHz profiler. J. Atmos. Sci., 51, 26312652, doi:10.1175/1520-0469(1994)051<2631:VMSIMC>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Cifelli, R., , and S. A. Rutledge, 1998: Vertical motion, diabatic heating, and rainfall characteristics in north Australia convective systems. Quart. J. Roy. Meteor. Soc., 124, 11331162, doi:10.1002/qj.49712454806.

    • Search Google Scholar
    • Export Citation
  • Collis, S., , A. Protat, , P. T. May, , and C. Williams, 2013: Statistics of storm updraft velocities from TWP-ICE including verification with profiling measurements. J. Appl. Meteor. Climatol., 52, 19091922, doi:10.1175/JAMC-D-12-0230.1.

    • Search Google Scholar
    • Export Citation
  • Davies, L., , C. Jakob, , P. T. May, , V. V. Kumar, , and S. Xie, 2013: Relationships between the large-scale atmosphere and the small-scale state for Darwin, Australia. J. Geophys. Res. Atmos., 118, 11 53411 545, doi:10.1002/jgrd.50645.

    • Search Google Scholar
    • Export Citation
  • Derbyshire, S. H., , I. Beau, , P. Bechtold, , J.-Y. Grandpeix, , J.-M. Piriou, , J.-L. Redelsperger, , and P. M. Soares, 2004: Sensitivity of moist convection to environmental humidity. Quart. J. Roy. Meteor. Soc., 130, 30553080, doi:10.1256/qj.03.130.

    • Search Google Scholar
    • Export Citation
  • Emanuel, K. A., , J. D. Neelin, , and C. S. Bretherton, 1994: On large-scale circulations in convecting atmospheres. Quart. J. Roy. Meteor. Soc., 120, 11111143, doi:10.1002/qj.49712051902.

    • Search Google Scholar
    • Export Citation
  • Fierro, A. O., , J. M. Simpson, , M. A. LeMone, , J. M. Straka, , and B. F. Smull, 2009: On how hot towers fuel the Hadley cell: An observational and modelling study of line-organized convection in the equatorial trough from TOGA COARE. J. Atmos. Sci., 66, 27302746, doi:10.1175/2009JAS3017.1.

    • Search Google Scholar
    • Export Citation
  • Fritsch, J. M., 1975: Cumulus dynamics: Local compensating subsidence and its implications for cumulus parameterization. Pure Appl. Geophys., 113, 851867, doi:10.1007/BF01592963.

    • Search Google Scholar
    • Export Citation
  • Giangrande, S. E., , S. Collis, , J. Straka, , A. Protat, , C. Williams, , and S. Krueger, 2013: A summary of convective-core vertical velocity properties using ARM UHF wind profilers in Oklahoma. J. Appl. Meteor. Climatol., 52, 22782295, doi:10.1175/JAMC-D-12-0185.1.

    • Search Google Scholar
    • Export Citation
  • Heymsfield, G. M., , L. Tian, , A. J. Heymsfield, , L. Li, , and S. Guimond, 2010: Characteristics of deep tropical and subtropical convection from nadir-viewing high-altitude airborne Doppler radar. J. Atmos. Sci., 67, 285308, doi:10.1175/2009JAS3132.1.

    • Search Google Scholar
    • Export Citation
  • Johnson, R. H., , T. M. Rickenbach, , S. A. Rutledge, , P. E. Ciesielski, , and W. H. Schubert, 1999: Trimodal characteristics of tropical convection. J. Climate, 12, 23972418, doi:10.1175/1520-0442(1999)012<2397:TCOTC>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Keenan, T. D., , K. Glasson, , F. Cummings, , T. S. Bird, , J. Keeler, , and J. Lutz, 1998: The BMRC/NCAR C-band polarimetric (CPOL) radar system. J. Atmos. Oceanic Technol., 15, 871886, doi:10.1175/1520-0426(1998)015<0871:TBNCBP>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Knupp, K. R., , and W. R. Cotton, 1985: Convective cloud downdraft structure: An interpretive survey. Rev. Geophys., 23, 183215, doi:10.1029/RG023i002p00183.

    • Search Google Scholar
    • Export Citation
  • Kuang, Z., , and C. S. Bretherton, 2006: A mass-flux scheme view of a high-resolution simulation of a transition from shallow to deep cumulus convection. J. Atmos. Sci., 63, 18951909, doi:10.1175/JAS3723.1.

    • Search Google Scholar
    • Export Citation
  • Kumar, V. V., , C. Jakob, , A. Protat, , P. T. May, , and L. Davies, 2013a: The four cumulus cloud modes and their progression during rainfall events: A C-band polarimetric radar perspective. J. Geophys. Res. Atmos., 118, 83758389, doi:10.1002/jgrd.50640.

    • Search Google Scholar
    • Export Citation
  • Kumar, V. V., , A. Protat, , P. T. May, , C. Jakob, , G. Penide, , S. Kumar, , and L. Davies, 2013b: On the effects of large-scale environment and surface conditions on convective cloud characteristics over Darwin, Australia. Mon. Wea. Rev., 141, 13581374, doi:10.1175/MWR-D-12-00160.1.

    • Search Google Scholar
    • Export Citation
  • Kumar, V. V., , A. Protat, , C. Jakob, , and P. T. May, 2014: On atmospheric regulation of the growth of moderate to deep cumulonimbus in a tropical environment. J. Atmos. Sci., 71, 11051120, doi:10.1175/JAS-D-13-0231.1.

    • Search Google Scholar
    • Export Citation
  • LeMone, M. A., , and E. J. Zipser, 1980: Cumulonimbus vertical velocity events in GATE. Part I: Diameter, intensity and mass-flux. J. Atmos. Sci., 37, 24442457, doi:10.1175/1520-0469(1980)037<2444:CVVEIG>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Liu, C., , and E. J. Zipser, 2005: Global distribution of convection penetrating the tropical tropopause. J. Geophys. Res., 110, D23104, doi:10.1029/2005JD006063.

    • Search Google Scholar
    • Export Citation
  • Marwitz, J. D., 1973: Trajectories within the weak echo regions of hailstorms. J. Appl. Meteor., 12, 11741182, doi:10.1175/1520-0450(1973)012<1174:TWTWER>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • May, P. T., , and D. K. Rajopadhyaya, 1999: Vertical velocity characteristics of deep convection over Darwin, Australia. Mon. Wea. Rev., 127, 10561071, doi:10.1175/1520-0493(1999)127<1056:VVCODC>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • May, P. T., , A. R. Jameson, , T. D. Keenan, , P. E. Johnston, , and C. Lucas, 2002: Combined wind profiler/polarimetric radar studies of the vertical motion and microphysical characteristics of tropical sea breeze thunderstorms. Mon. Wea. Rev., 130, 22282239, doi:10.1175/1520-0493(2002)130<2228:CWPPRS>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • May, P. T., , J. H. Mather, , G. Vaughan, , C. Jakob, , G. M. McFarquhar, , K. N. Bower, , and G. G. Mace, 2008: The Tropical Warm Pool International Cloud Experiment. Bull. Amer. Meteor. Soc., 89, 629645, doi:10.1175/BAMS-89-5-629.

    • Search Google Scholar
    • Export Citation
  • Paluch, I. R., , and C. A. Knight, 1984: Mixing and evolution of cloud droplet size spectra in a vigorous continental cumulus. J. Atmos. Sci., 41, 18011815, doi:10.1175/1520-0469(1984)041<1801:MATEOC>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Penide, G., , V. V. Kumar, , A. Protat, , and P. T. May, 2013: Statistics of drop size distribution parameters and rain rates for stratiform and convective precipitation during the North Australian wet season. Mon. Wea. Rev., 141, 32223237, doi:10.1175/MWR-D-12-00262.1.

    • Search Google Scholar
    • Export Citation
  • Petch, J., , A. Hill, , L. Davies, , A. Fridlind, , C. Jakob, , Y. Lin, , S. Xie, , and P. Zhu, 2014: Evaluation of intercomparisons of four different types of models simulating TWP-ICE. Quart. J. Roy. Meteor. Soc., 140, 826837, doi:10.1002/qj.2192.

    • Search Google Scholar
    • Export Citation
  • Pope, M., , C. Jakob, , and M. Reeder, 2009: Regimes of the north Australian wet season. J. Climate, 22, 66996715, doi:10.1175/2009JCLI3057.1.

    • Search Google Scholar
    • Export Citation
  • Protat, A., , and I. Zawadzki, 1999: A variational method for real-time retrieval of three-dimensional wind field from multiple-Doppler bistatic radar network data. J. Atmos. Oceanic Technol., 16, 432449, doi:10.1175/1520-0426(1999)016<0432:AVMFRT>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Protat, A., , and C. R. Williams, 2011: The accuracy of radar estimates of ice terminal fall speed from vertically pointing Doppler radar measurements. J. Appl. Meteor. Climatol., 50, 21202138, doi:10.1175/JAMC-D-10-05031.1.

    • Search Google Scholar
    • Export Citation
  • Randall, D. A., and Coauthors, 2003: Confronting models with data - The GEWEX Cloud Systems Study. Bull. Amer. Meteor. Soc., 84, 455469, doi:10.1175/BAMS-84-4-455.

    • Search Google Scholar
    • Export Citation
  • Redelsperger, J.-L., , D. B. Parsons, , and F. Guichard, 2002: Recovery processes and factors limiting cloud-top height following the arrival of a dry intrusion observed during TOGA COARE. J. Atmos. Sci., 59, 24382457, doi:10.1175/1520-0469(2002)059<2438:RPAFLC>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Smull, B. F., , and R. A. Houze Jr., 1987: Dual-Doppler radar analysis of a midlatitude squall line with a trailing region of stratiform rain. J. Atmos. Sci., 44, 21282148, doi:10.1175/1520-0469(1987)044<2128:DDRAOA>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Steiner, M., , R. A. Houze Jr., , and S. E. Yuter, 1995: Climatological characterization of three-dimensional storm structure from operational radar and rain gauge data. J. Appl. Meteor., 34, 19782007, doi:10.1175/1520-0450(1995)034<1978:CCOTDS>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Sun, J., , S. Braun, , M. I. Biggerstaff, , R. G. Fovell, , and R. A. Houze Jr., 1993: Warm upper-level downdrafts associated with a squall line. Mon. Wea. Rev., 121, 29192927, doi:10.1175/1520-0493(1993)121<2919:WULDAW>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Takemi, T., , O. Hirayama, , and C. Liu, 2004: Factors responsible for the vertical development of tropical oceanic cumulus convection. Geophys. Res. Lett., 31, L11109, doi:10.1029/2004GL020225.

    • Search Google Scholar
    • Export Citation
  • Williams, C. R., 2012: Vertical air motion retrieved from dual-frequency profiler observations. J. Atmos. Oceanic Technol., 29, 14711480, doi:10.1175/JTECH-D-11-00176.1.

    • Search Google Scholar
    • Export Citation
  • Xie, S., , R. T. Cederwall, , and M. Zhang, 2004: Developing long-term single-column model/cloud system–resolving model forcing data using numerical weather prediction products constrained by surface and top of the atmosphere observations. J. Geophys. Res., 109, D01104, doi:10.1029/2003JD004045.

    • Search Google Scholar
    • Export Citation
  • Yanai, M., , S. Esbensen, , and J. Chu, 1973: Determination of bulk properties of tropical cloud clusters from large-scale heat and moisture budgets. J. Atmos. Sci., 30, 611627, doi:10.1175/1520-0469(1973)030<0611:DOBPOT>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Zhang, M., , and J. Lin, 1997: Constrained variational analysis of sounding data based on column-integrated budgets of mass, heat, moisture, and momentum: Approach and application to ARM measurements. J. Atmos. Sci., 54, 15031524, doi:10.1175/1520-0469(1997)054<1503:CVAOSD>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Zipser, E. J., 2003: Some view on “hot towers” after 50 years of tropical field programs and two years of TRMM data. Cloud Systems, Hurricanes, and the TRMM, Meteor. Monogr., No. 51, Amer. Meteor. Soc., 49–58.

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Mass-Flux Characteristics of Tropical Cumulus Clouds from Wind Profiler Observations at Darwin, Australia

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  • 1 School of Earth, Atmosphere and Environment, Monash University, Melbourne, Victoria, Australia
  • 2 School of Earth, Atmosphere and Environment, and Australian Research Council Centre of Excellence for Climate System Science, Monash University, Melbourne, Victoria, Australia
  • 3 Centre for Australian Weather and Climate Research, Melbourne, Victoria, Australia
  • 4 University of Colorado Boulder, and NOAA/Earth System Research Laboratory/Physical Sciences Division, Boulder, Colorado
  • 5 Centre for Australian Weather and Climate Research, Melbourne, Victoria, Australia
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Abstract

Cumulus parameterizations in weather and climate models frequently apply mass-flux schemes in their description of tropical convection. Mass flux constitutes the product of the fractional area covered by convection in a model grid box and the vertical velocity in cumulus clouds. However, vertical velocities are difficult to observe on GCM scales, making the evaluation of mass-flux schemes difficult. Here, the authors combine high-temporal-resolution observations of in-cloud vertical velocities derived from a pair of wind profilers over two wet seasons at Darwin with physical properties of precipitating clouds [cloud-top heights (CTH), convective–stratiform classification] derived from the Darwin C-band polarimetric radar to provide estimates of cumulus mass flux and its constituents. The length of this dataset allows for investigations of the contributions from different cumulus cloud types—namely, congestus, deep, and overshooting convection—to the overall mass flux and of the influence of large-scale conditions on mass flux. The authors found that mass flux was dominated by updrafts and, in particular, the updraft area fraction, with updraft vertical velocity playing a secondary role. The updraft vertical velocities peaked above 10 km where both the updraft area fractions and air densities were small, resulting in a marginal effect on mass-flux values. Downdraft area fractions are much smaller and velocities are much weaker than those in updrafts. The area fraction responded strongly to changes in midlevel large-scale vertical motion and convective inhibition (CIN). In contrast, changes in the lower-tropospheric relative humidity and convective available potential energy (CAPE) strongly modulate in-cloud vertical velocities but have moderate impacts on area fractions. Although average mass flux is found to increase with increasing CTH, it is the environmental conditions that seem to dictate the magnitude of mass flux produced by convection through a combination of effects on area fraction and velocity.

Corresponding author address: Vickal V. Kumar, Centre for Australian Weather and Climate Research, Australian Bureau of Meteorology and CSIRO, GPO Box 1289, Melbourne VIC 3001, Australia. E-mail: v.kumar@bom.gov.au

Abstract

Cumulus parameterizations in weather and climate models frequently apply mass-flux schemes in their description of tropical convection. Mass flux constitutes the product of the fractional area covered by convection in a model grid box and the vertical velocity in cumulus clouds. However, vertical velocities are difficult to observe on GCM scales, making the evaluation of mass-flux schemes difficult. Here, the authors combine high-temporal-resolution observations of in-cloud vertical velocities derived from a pair of wind profilers over two wet seasons at Darwin with physical properties of precipitating clouds [cloud-top heights (CTH), convective–stratiform classification] derived from the Darwin C-band polarimetric radar to provide estimates of cumulus mass flux and its constituents. The length of this dataset allows for investigations of the contributions from different cumulus cloud types—namely, congestus, deep, and overshooting convection—to the overall mass flux and of the influence of large-scale conditions on mass flux. The authors found that mass flux was dominated by updrafts and, in particular, the updraft area fraction, with updraft vertical velocity playing a secondary role. The updraft vertical velocities peaked above 10 km where both the updraft area fractions and air densities were small, resulting in a marginal effect on mass-flux values. Downdraft area fractions are much smaller and velocities are much weaker than those in updrafts. The area fraction responded strongly to changes in midlevel large-scale vertical motion and convective inhibition (CIN). In contrast, changes in the lower-tropospheric relative humidity and convective available potential energy (CAPE) strongly modulate in-cloud vertical velocities but have moderate impacts on area fractions. Although average mass flux is found to increase with increasing CTH, it is the environmental conditions that seem to dictate the magnitude of mass flux produced by convection through a combination of effects on area fraction and velocity.

Corresponding author address: Vickal V. Kumar, Centre for Australian Weather and Climate Research, Australian Bureau of Meteorology and CSIRO, GPO Box 1289, Melbourne VIC 3001, Australia. E-mail: v.kumar@bom.gov.au
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