A Synthetic Aperture Radar–Based Climatology of Open-Cell Convection over the Northeast Pacific Ocean

Todd D. Sikora Department of Earth Sciences, Millersville University, Millersville, Pennsylvania

Search for other papers by Todd D. Sikora in
Current site
Google Scholar
PubMed
Close
,
George S. Young Department of Meteorology, The Pennsylvania State University, University Park, Pennsylvania

Search for other papers by George S. Young in
Current site
Google Scholar
PubMed
Close
,
Caren M. Fisher Department of Meteorology, The Pennsylvania State University, University Park, Pennsylvania

Search for other papers by Caren M. Fisher in
Current site
Google Scholar
PubMed
Close
, and
Matthew D. Stepp Department of Earth Sciences, Millersville University, Millersville, Pennsylvania

Search for other papers by Matthew D. Stepp in
Current site
Google Scholar
PubMed
Close
Restricted access

Abstract

This paper presents an 8-yr (1999–2006) climatology of the frequency of open-cell convection over the northeastern Pacific Ocean and the thermodynamic and kinematic environment associated with its development. The climatology is based on synthetic aperture radar–derived wind speed images and reanalysis data. The climatology shows that open-cell convection was a cold-season phenomenon, having occurred in environments in which the difference in temperature between the near-surface air and the sea surface is negative and in environments with positive surface sensible and latent heat fluxes. Within the region between the surface and 500 hPa, the 700–850-hPa layer median static stability was near moist adiabatic while that for the remainder was conditionally unstable. The median magnitude of the vertical wind shear was largest in the 925-hPa–near-surface and 500–700-hPa layers while that at midlevels was relatively weak. Similarities are highlighted between the organization of open-cell convection over the northeastern Pacific Ocean and tropical deep moist maritime convection in terms of cold-pool dynamics. Avenues for future work are discussed.

Corresponding author address: Todd D. Sikora, Dept. of Earth Sciences, Millersville University, Millersville, PA 17551. Email: todd.sikora@millersville.edu

Abstract

This paper presents an 8-yr (1999–2006) climatology of the frequency of open-cell convection over the northeastern Pacific Ocean and the thermodynamic and kinematic environment associated with its development. The climatology is based on synthetic aperture radar–derived wind speed images and reanalysis data. The climatology shows that open-cell convection was a cold-season phenomenon, having occurred in environments in which the difference in temperature between the near-surface air and the sea surface is negative and in environments with positive surface sensible and latent heat fluxes. Within the region between the surface and 500 hPa, the 700–850-hPa layer median static stability was near moist adiabatic while that for the remainder was conditionally unstable. The median magnitude of the vertical wind shear was largest in the 925-hPa–near-surface and 500–700-hPa layers while that at midlevels was relatively weak. Similarities are highlighted between the organization of open-cell convection over the northeastern Pacific Ocean and tropical deep moist maritime convection in terms of cold-pool dynamics. Avenues for future work are discussed.

Corresponding author address: Todd D. Sikora, Dept. of Earth Sciences, Millersville University, Millersville, PA 17551. Email: todd.sikora@millersville.edu

Save
  • Agee, E. M., 1987: Mesoscale cellular convection over the oceans. Dyn. Atmos. Oceans, 10 , 317341.

  • Agee, E. M., and K. E. Dowell, 1974: Observational studies of mesoscale cellular convection. J. Appl. Meteor., 13 , 4653.

  • Agee, E. M., and F. E. Lomax, 1978: Morphology of the mixed layer and inversion layer associated with patterns of mesoscale cellular convection during AMTEX 75. J. Atmos. Sci., 35 , 22812301.

    • Search Google Scholar
    • Export Citation
  • Albrecht, B. A., D. A. Randall, and S. Nicholls, 1988: Observations of marine stratocumulus clouds during FIRE. Bull. Amer. Meteor. Soc., 69 , 618626.

    • Search Google Scholar
    • Export Citation
  • Albrecht, B. A., C. S. Bretherton, D. Johnson, W. H. Schubert, and A. S. Frisch, 1995: The Atlantic Stratocumulus Transition Experiment—ASTEX. Bull. Amer. Meteor. Soc., 76 , 889902.

    • Search Google Scholar
    • Export Citation
  • Alexander, G. D., and G. S. Young, 1992: The relationship between EMEX mesoscale precipitation feature properties and their environmental characteristics. Mon. Wea. Rev., 120 , 554564.

    • Search Google Scholar
    • Export Citation
  • Asai, T., 1970: Stability of a plane parallel flow with variable vertical shear and unstable stratification. J. Meteor. Soc. Japan, 48 , 129139.

    • Search Google Scholar
    • Export Citation
  • Asai, T., and I. Nakasuji, 1973: On the stability of Ekman boundary layer flow with thermally unstable stratification. J. Meteor. Soc. Japan, 51 , 2942.

    • Search Google Scholar
    • Export Citation
  • Atkinson, B. W., and J. W. Zhang, 1996: Mesoscale shallow convection in the atmosphere. Rev. Geophys., 34 , 403431.

  • Barnes, G. M., and M. Garstang, 1982: Subcloud layer energetics of precipitating convection. Mon. Wea. Rev., 110 , 102117.

  • Barnes, G. M., and K. Sieckman, 1984: The environment of fast- and slow-moving tropical mesoscale convective lines. Mon. Wea. Rev., 112 , 17821794.

    • Search Google Scholar
    • Export Citation
  • Beal, R. C., G. S. Young, F. M. Monaldo, D. R. Thompson, N. S. Winstead, and C. A. Scott, 2005: High Resolution Wind Monitoring with Wide Swath SAR: A User’s Guide. U.S. Department of Commerce, 164 pp.

    • Search Google Scholar
    • Export Citation
  • Bond, N. A., and R. G. Fleagle, 1988: Prefrontal and postfrontal boundary layer processes over the ocean. Mon. Wea. Rev., 116 , 12571273.

    • Search Google Scholar
    • Export Citation
  • Bretherton, C. S., and Coauthors, 2004: The EPIC 2001 Stratocumulus Study. Bull. Amer. Meteor. Soc., 85 , 967977.

  • Brümmer, B., 1997: Boundary layer mass, water, and heat budgets in wintertime cold-air outbreaks from the Arctic sea ice. Mon. Wea. Rev., 125 , 18241837.

    • Search Google Scholar
    • Export Citation
  • Brümmer, B., 1999: Roll and cell convection in wintertime arctic cold-air outbreaks. J. Atmos. Sci., 56 , 26132636.

  • Brümmer, B., S. Bakan, and H. Hinzpeter, 1985: KonTur: Observations of cloud streets and open cellular structures. Dyn. Atmos. Oceans, 9 , 281296.

    • Search Google Scholar
    • Export Citation
  • Chlond, A., 1988: Numerical and analytical studies of diabatic heating effect upon flatness of boundary layer rolls. Contrib. Atmos. Phys., 61 , 312329.

    • Search Google Scholar
    • Export Citation
  • Comstock, K. K., C. S. Bretherton, and S. E. Yuter, 2005: Mesoscale variability and drizzle in southeast Pacific stratocumulus. J. Atmos. Sci., 62 , 37923807.

    • Search Google Scholar
    • Export Citation
  • Comstock, K. K., S. E. Yuter, R. Wood, and C. S. Bretherton, 2007: The three-dimensional structure and kinematics of drizzling stratocumulus. Mon. Wea. Rev., 135 , 37673784.

    • Search Google Scholar
    • Export Citation
  • Eastman, R., and S. G. Warren, 2010: Interannual variations of Arctic cloud types in relation to sea ice. J. Climate, 23 , 42164232.

  • Hersbach, H., A. Stoffelen, and S. de Haan, 2007: An improved C-band scatterometer ocean geophysical model function: CMOD5. J. Geophys. Res., 112 , C03006. doi:10.1029/2006JC003743.

    • Search Google Scholar
    • Export Citation
  • International and Scientific Management Group of GATE, 1974: GATE. Bull. Amer. Meteor. Soc., 55 , 711744.

  • Jackson, C. R., and J. R. Apel, 2004: Synthetic Aperture Radar Marine User’s Manual. U.S. Department of Commerce, 464 pp.

  • Johnson, R. H., S. L. Aves, P. E. Ciesielski, and T. D. Keenan, 2005: Organization of oceanic convection during the onset of the 1998 East Asian summer monsoon. Mon. Wea. Rev., 133 , 131148.

    • Search Google Scholar
    • Export Citation
  • Kalnay, E., and Coauthors, 1996: The NCEP/NCAR 40-Year Reanalysis Project. Bull. Amer. Meteor. Soc., 77 , 437471.

  • King, M. D., Y. J. Kaufman, W. P. Menzel, and D. Tanre, 1992: Remote-sensing of cloud, aerosol, and water-vapor properties from the Moderate Resolution Imaging Spectrometer (MODIS). IEEE Trans. Geosci. Remote Sens., 30 , 227.

    • Search Google Scholar
    • Export Citation
  • Lau, K. M., and Coauthors, 2000: A report of the field operations and early results of the South China Sea Monsoon Experiment (SCSMEX). Bull. Amer. Meteor. Soc., 81 , 12611270.

    • Search Google Scholar
    • Export Citation
  • LeMone, M. A., 1973: The structure and dynamics of horizontal roll vortices in the planetary boundary layer. J. Atmos. Sci., 30 , 10771091.

    • Search Google Scholar
    • Export Citation
  • LeMone, M. A., G. M. Barnes, E. J. Szoke, and E. J. Zipser, 1984: The tilt of the leading edge of mesoscale tropical convective lines. Mon. Wea. Rev., 112 , 510519.

    • Search Google Scholar
    • Export Citation
  • LeMone, M. A., E. J. Zipser, and S. B. Trier, 1998: The role of shear and thermodynamic conditions in determining the structure and evolution of mesoscale convective systems during TOGA COARE. J. Atmos. Sci., 55 , 34933518.

    • Search Google Scholar
    • Export Citation
  • Lenschow, D. H., and E. M. Agee, 1974: The Air Mass Transformation Experiment (AMTEX): Preliminary results from 1974 and plans for 1975. Bull. Amer. Meteor. Soc., 55 , 12281235.

    • Search Google Scholar
    • Export Citation
  • Lenschow, D. H., and Coauthors, 1988: Dynamics and Chemistry of Marine Stratocumulus (DYCOMS) Experiment. Bull. Amer. Meteor. Soc., 69 , 10581067.

    • Search Google Scholar
    • Export Citation
  • Markowski, P., and Y. Richardson, 2010: Mesoscale Meteorology in Midlatitudes. Wiley-Blackwell, 407 pp.

  • Miura, Y., 1986: Aspect ratios of longitudinal rolls and convection cells observed during cold air outbreaks. J. Atmos. Sci., 43 , 2639.

    • Search Google Scholar
    • Export Citation
  • Moncrieff, M. W., and C. Liu, 1999: Convection initiation by density currents: Role of convergence, shear, and dynamical organization. Mon. Wea. Rev., 127 , 24552464.

    • Search Google Scholar
    • Export Citation
  • Moyer, K. A., and G. S. Young, 1994: Observations of mesoscale cellular convection from the marine stratocumulus phase of FIRE. Bound.-Layer Meteor., 71 , 109133.

    • Search Google Scholar
    • Export Citation
  • Painemal, D., R. Garreaud, J. Rutllant, and P. Zuidema, 2010: Southeast Pacific stratocumulus: High-frequency variability and mesoscale structures over San Félix Island. J. Appl. Meteor. Climatol., 49 , 463477.

    • Search Google Scholar
    • Export Citation
  • Randall, D., and Coauthors, 2003: Confronting models with data: The GEWEX Cloud System Study. Bull. Amer. Meteor. Soc., 84 , 455469.

  • Rauber, R. M., and Coauthors, 2007: Rain in shallow cumulus over the ocean: The RICO campaign. Bull. Amer. Meteor. Soc., 88 , 19121928.

    • Search Google Scholar
    • Export Citation
  • Savic-Jovic, V., and B. Stevens, 2008: The structure and mesoscale organization of precipitating stratocumulus. J. Atmos. Sci., 65 , 15871605.

    • Search Google Scholar
    • Export Citation
  • Schröter, M., S. Raasch, and H. Jansen, 2005: Cell broadening revisited: Results from high-resolution large-eddy simulations of cold air outbreaks. J. Atmos. Sci., 62 , 20232032.

    • Search Google Scholar
    • Export Citation
  • Sharon, T. M., B. A. Albrecht, H. H. Jonsson, P. Minnis, M. M. Khaiyer, T. M. van Reken, J. Seinfeld, and R. Flagan, 2006: Aerosol and cloud microphysical characteristics of rifts and gradients in maritime stratocumulus clouds. J. Atmos. Sci., 63 , 983997.

    • Search Google Scholar
    • Export Citation
  • Sheu, P. J., and E. M. Agee, 1977: Kinematic analysis and air–sea heat flux associated with mesoscale cellular convection during AMTEX 75. J. Atmos. Sci., 34 , 793801.

    • Search Google Scholar
    • Export Citation
  • Sikora, T. D., G. S. Young, R. C. Beal, F. M. Monaldo, and P. W. Vachon, 2006: Applications of synthetic aperture radar in marine meteorology. Atmosphere–Ocean Interactions, W. Perrie, Ed., WIT Press, 83–113.

    • Search Google Scholar
    • Export Citation
  • Snodgrass, E. R., L. Di Girolamo, and R. M. Rauber, 2009: Precipitation characteristics of trade wind clouds during RICO derived from radar, satellite, and aircraft measurements. J. Appl. Meteor. Climatol., 48 , 464483.

    • Search Google Scholar
    • Export Citation
  • Stevens, B., and Coauthors, 2003: Dynamics and chemistry of marine stratocumulus—DYCOMS-II. Bull. Amer. Meteor. Soc., 84 , 579593.

  • Stoffelen, A., and D. Anderson, 1997: Scatterometer data interpretation: Estimation and validation of the transfer function CMOD4. J. Geophys. Res., 102 , 57675780.

    • Search Google Scholar
    • Export Citation
  • Uttal, T., and Coauthors, 2002: Surface heat budget of the Arctic Ocean. Bull. Amer. Meteor. Soc., 83 , 255275.

  • vanZanten, M. C., and B. Stevens, 2005: Observations of the structure of heavily precipitating marine stratocumulus. J. Atmos. Sci., 62 , 43274342.

    • Search Google Scholar
    • Export Citation
  • Verlinde, J., and Coauthors, 2007: The Mixed-Phase Arctic Cloud Experiment. Bull. Amer. Meteor. Soc., 88 , 205221.

  • Wang, H., and G. Feingold, 2009: Modeling mesoscale cellular structures and drizzle in marine stratocumulus. Part I: Impact of drizzle on the formation and evolution of open cells. J. Atmos. Sci., 66 , 32373256.

    • Search Google Scholar
    • Export Citation
  • Webster, P. J., and R. A. Houze Jr., 1991: The Equatorial Mesoscale Experiment (EMEX): An overview. Bull. Amer. Meteor. Soc., 72 , 14811505.

    • Search Google Scholar
    • Export Citation
  • Webster, P. J., and R. Lukas, 1992: TOGA COARE: The Coupled Ocean–Atmosphere Response Experiment. Bull. Amer. Meteor. Soc., 73 , 13771416.

    • Search Google Scholar
    • Export Citation
  • Weckwerth, T. M., J. W. Wilson, R. M. Wakimoto, and N. A. Crook, 1997: Horizontal convective rolls: Determining the environmental conditions supporting their existence and characteristics. Mon. Wea. Rev., 125 , 505526.

    • Search Google Scholar
    • Export Citation
  • Weckwerth, T. M., T. W. Horst, and J. W. Wilson, 1999: An observational study of the evolution of horizontal convective rolls. Mon. Wea. Rev., 127 , 21602179.

    • Search Google Scholar
    • Export Citation
  • Xue, H., G. Feingold, and B. Stevens, 2008: Aerosol effects on clouds, precipitation, and the organization of shallow cumulus convection. J. Atmos. Sci., 65 , 392406.

    • Search Google Scholar
    • Export Citation
  • Young, G. S., D. A. R. Kristovich, M. R. Hjelmfelt, and R. C. Foster, 2002: Rolls, streets, waves, and more: A review of quasi-two-dimensional morphology in the atmospheric boundary layer. Bull. Amer. Meteor. Soc., 83 , 9971001.

    • Search Google Scholar
    • Export Citation
  • Young, G. S., T. D. Sikora, and C. M. Fisher, 2007: Use of MODIS and synthetic aperture radar wind speed imagery to describe the morphology of open cell convection. Can. J. Remote Sens., 33 , 357367.

    • Search Google Scholar
    • Export Citation
  • Zipser, E. J., 1977: Mesoscale and convective–scale downdrafts as distinct components of squall-line morphology. Mon. Wea. Rev., 105 , 15681589.

    • Search Google Scholar
    • Export Citation
  • Zurn-Birkhimer, S. M., E. A. Agee, and Z. Sorbjan, 2005: Convective structures in a cold air outbreak over Lake Michigan during Lake-ICE. J. Atmos. Sci., 62 , 24142432.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 218 42 0
PDF Downloads 149 21 2