Editorial Type:
Article
Article Type:
Research Article

Large-Eddy Simulations of Convective Boundary Layers over Flat and Urbanlike Surfaces

Seung-Bu Park School of Earth and Environmental Sciences, Seoul National University, Seoul, South Korea

Search for other papers by Seung-Bu Park in
Current site
Google Scholar
PubMed Close
and
Jong-Jin Baik School of Earth and Environmental Sciences, Seoul National University, Seoul, South Korea

Search for other papers by Jong-Jin Baik in
Current site
Google Scholar
PubMed Close
Print Publication:
01 May 2014
DOI:
https://doi.org/10.1175/JAS-D-13-0191.1
Page(s):
1880–1892
Restricted access

Abstract

The effects of urbanlike surfaces with a block array on the dry convective boundary layer (CBL) are numerically investigated using the parallelized large-eddy simulation model. Five cases representing a free CBL, a sheared CBL, and a strongly sheared CBL over flat surfaces, a sheared CBL over a block array, and a sheared CBL over a modeled canopy layer are simulated and compared. In the sheared CBL over a block array, mixed-layer flow is decelerated because of increased surface shear and horizontal convective rolls appear in the mixed layer. In contrast, convection cells and intermediate structures between cells and rolls occur in the free and sheared CBLs over flat surfaces, respectively. Horizontal convective rolls and the traces of block-induced turbulent eddies are detected in the spectral density fields of vertical velocity and in the vertical profiles of vertical velocity skewness in the sheared CBL over a block array. The decelerated mixed-layer flow in the sheared CBL over a block array leads to stronger wind shear in the entrainment zone than in the other cases, resulting in streamwise alternating updrafts and downdrafts there. While the contributions to vertical turbulent heat flux by rising cool air and sinking cool air are dominant in the free CBL, the contributions to vertical turbulent heat flux by sinking warm air and rising warm air increase as the wind shear in the entrainment zone increases. Because of enhanced turbulence activity and wavelike motions in the entrainment zone, the magnitude of entrainment heat flux in the CBL over a block array is larger than that in the other cases.

Corresponding author address: Jong-Jin Baik, School of Earth and Environmental Sciences, Seoul National University, Seoul 151-742, South Korea. E-mail: jjbaik@snu.ac.kr

Abstract

The effects of urbanlike surfaces with a block array on the dry convective boundary layer (CBL) are numerically investigated using the parallelized large-eddy simulation model. Five cases representing a free CBL, a sheared CBL, and a strongly sheared CBL over flat surfaces, a sheared CBL over a block array, and a sheared CBL over a modeled canopy layer are simulated and compared. In the sheared CBL over a block array, mixed-layer flow is decelerated because of increased surface shear and horizontal convective rolls appear in the mixed layer. In contrast, convection cells and intermediate structures between cells and rolls occur in the free and sheared CBLs over flat surfaces, respectively. Horizontal convective rolls and the traces of block-induced turbulent eddies are detected in the spectral density fields of vertical velocity and in the vertical profiles of vertical velocity skewness in the sheared CBL over a block array. The decelerated mixed-layer flow in the sheared CBL over a block array leads to stronger wind shear in the entrainment zone than in the other cases, resulting in streamwise alternating updrafts and downdrafts there. While the contributions to vertical turbulent heat flux by rising cool air and sinking cool air are dominant in the free CBL, the contributions to vertical turbulent heat flux by sinking warm air and rising warm air increase as the wind shear in the entrainment zone increases. Because of enhanced turbulence activity and wavelike motions in the entrainment zone, the magnitude of entrainment heat flux in the CBL over a block array is larger than that in the other cases.

Corresponding author address: Jong-Jin Baik, School of Earth and Environmental Sciences, Seoul National University, Seoul 151-742, South Korea. E-mail: jjbaik@snu.ac.kr
Save
Cover Journal of the Atmospheric Sciences
Journal of the Atmospheric Sciences

  • Barlow, J. F., G. G. Rooney, S. von Hünerbein, and S. G. Bradley, 2008: Relating urban surface-layer structure to upwind terrain for the Salford experiment (Salfex). Bound.-Layer Meteor., 127, 173–191, doi:10.1007/s10546-007-9261-y.

    • Search Google Scholar
    • Export Citation

  • Castillo, M. C., A. Inagaki, and M. Kanda, 2011: The effects of inner- and outer-layer turbulence in a convective boundary layer on the near-neutral inertial sublayer over an urban-like surface. Bound.-Layer Meteor., 140, 453–469, doi:10.1007/s10546-011-9614-4.

    • Search Google Scholar
    • Export Citation

  • Coceal, O., A. Dobre, and T. G. Thomas, 2007: Unsteady dynamics and organized structures from DNS over an idealized building canopy. Int. J. Climatol., 27, 1943–1953, doi:10.1002/joc.1549.

    • Search Google Scholar
    • Export Citation

  • Conzemius, R. J., and E. Fedorovich, 2006: Dynamics of sheared convective boundary layer entrainment. Part I: Methodological background and large-eddy simulations. J. Atmos. Sci., 63, 1151–1178, doi:10.1175/JAS3691.1.

    • Search Google Scholar
    • Export Citation

  • Deardorff, J. W., 1980: Stratocumulus-capped mixed layers derived from a three-dimensional model. Bound.-Layer Meteor., 18, 495–527, doi:10.1007/BF00119502.

    • Search Google Scholar
    • Export Citation

  • Emeis, S., K. Baumann-Stanzer, M. Piringer, M. Kallistratova, R. Kouznetsov, and V. Yushkov, 2007: Wind and turbulence in the urban boundary layer—Analysis from acoustic remote sensing data and fit to analytical relations. Meteor. Z., 16, 393–406, doi:10.1127/0941-2948/2007/0217.

    • Search Google Scholar
    • Export Citation

  • Harman, I. N., and J. J. Finnigan, 2007: A simple unified theory for flow in the canopy and roughness sublayer. Bound.-Layer Meteor., 123, 339–363, doi:10.1007/s10546-006-9145-6.

    • Search Google Scholar
    • Export Citation

  • Inagaki, A., and M. Kanda, 2010: Organized structure of active turbulence over an array of cubes within the logarithmic layer of atmospheric flow. Bound.-Layer Meteor., 135, 209–228, doi:10.1007/s10546-010-9477-0.

    • Search Google Scholar
    • Export Citation

  • Inagaki, A., M. C. L. Castillo, Y. Yamashita, M. Kanda, and H. Takimoto, 2012: Large-eddy simulation of coherent flow structures within a cubical canopy. Bound.-Layer Meteor., 142, 207–222, doi:10.1007/s10546-011-9671-8.

    • Search Google Scholar
    • Export Citation

  • Iwai, H., and Coauthors, 2008: Dual-Doppler lidar observation of horizontal convective rolls and near-surface streaks. Geophys. Res. Lett., 35, L14808, doi:10.1029/2008GL034571.

    • Search Google Scholar
    • Export Citation

  • Kanda, M., A. Inagaki, T. Miyamoto, M. Gryschka, and S. Raasch, 2013: A new aerodynamic parametrization for real urban surfaces. Bound.-Layer Meteor., 148, 357–377, doi:10.1007/s10546-013-9818-x.

    • Search Google Scholar
    • Export Citation

  • Khanna, S., and J. G. Brasseur, 1998: Three-dimensional buoyancy- and shear-induced local structure of the atmospheric boundary layer. J. Atmos. Sci., 55, 710–743, doi:10.1175/1520-0469(1998)055<0710:TDBASI>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Kim, S.-W., and S.-U. Park, 2003: Coherent structures near the surface in a strongly sheared convective boundary layer generated by large-eddy simulation. Bound.-Layer Meteor., 106, 35–60, doi:10.1023/A:1020811015189.

    • Search Google Scholar
    • Export Citation

  • Kim, S.-W., S.-U. Park, and C.-H. Moeng, 2003: Entrainment processes in the convective boundary layer with varying wind shear. Bound.-Layer Meteor., 108, 221–245, doi:10.1023/A:1024170229293.

    • Search Google Scholar
    • Export Citation

  • Kropfli, R. A., and N. M. Kohn, 1978: Persistent horizontal rolls in the urban mixed layer as revealed by dual-Doppler radar. J. Appl. Meteor., 17, 669–676, doi:10.1175/1520-0450(1978)017<0669:PHRITU>2.0.CO;2.

    • 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, 1077–1091, doi:10.1175/1520-0469(1973)030<1077:TSADOH>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Letzel, M. O., M. Krane, and S. Raasch, 2008: High resolution urban large-eddy simulation studies from street canyon to neighbourhood scale. Atmos. Environ., 42, 8770–8784, doi:10.1016/j.atmosenv.2008.08.001.

    • Search Google Scholar
    • Export Citation

  • Lin, C.-L., C.-H. Moeng, P. P. Sullivan, and J. C. McWilliams, 1997: The effect of surface roughness on flow structures in a neutrally stratified planetary boundary layer flow. Phys. Fluids, 9, 3235–3249, doi:10.1063/1.869439.

    • Search Google Scholar
    • Export Citation

  • Macdonald, R. W., 2000: Modelling the mean velocity profile in the urban canopy layer. Bound.-Layer Meteor., 97, 25–45, doi:10.1023/A:1002785830512.

    • Search Google Scholar
    • Export Citation

  • Miao, Q., B. Geerts, and M. LeMone, 2006: Vertical velocity and buoyancy characteristics of coherent echo plumes in the convective boundary layer, detected by a profiling airborne radar. J. Appl. Meteor. Climatol., 45, 838–855, doi:10.1175/JAM2375.1.

    • Search Google Scholar
    • Export Citation

  • Miao, S., and F. Chen, 2008: Formation of horizontal convective rolls in urban areas. Atmos. Res., 89, 298–304, doi:10.1016/j.atmosres.2008.02.013.

    • Search Google Scholar
    • Export Citation

  • Moeng, C.-H., and P. P. Sullivan, 1994: A comparison of shear- and buoyancy-driven planetary boundary layer flows. J. Atmos. Sci., 51, 999–1022, doi:10.1175/1520-0469(1994)051<0999:ACOSAB>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Newsom, R., R. Calhoun, D. Ligon, and J. Allwine, 2008: Linearly organized turbulence structures observed over a suburban area by dual-Doppler lidar. Bound.-Layer Meteor., 127, 111–130, doi:10.1007/s10546-007-9243-0.

    • Search Google Scholar
    • Export Citation

  • Park, S.-B., and J.-J. Baik, 2013: A large-eddy simulation study of thermal effects on turbulence coherent structures in and above a building array. J. Appl. Meteor. Climatol, 52, 1348–1365, doi:10.1175/JAMC-D-12-0162.1.

    • Search Google Scholar
    • Export Citation

  • Piacsek, S. A., and G. P. Williams, 1970: Conservation properties of convection difference schemes. J. Comput. Phys., 6, 392–405, doi:10.1016/0021-9991(70)90038-0.

    • Search Google Scholar
    • Export Citation

  • Pino, D., and J. Vilà-Guerau de Arellano, 2008: Effects of shear in the convective boundary layer: Analysis of the turbulent kinetic energy budget. Acta Geophys, 56, 167–193, doi:10.2478/s11600-007-0037-z.

    • Search Google Scholar
    • Export Citation

  • Raasch, S., and D. Etling, 1998: Modeling deep ocean convection: Large eddy simulation in comparison with laboratory experiments. J. Phys. Oceanogr., 28, 1786–1802, doi:10.1175/1520-0485(1998)028<1786:MDOCLE>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Raasch, S., and M. Schröter, 2001: PALM—A large-eddy simulation model performing on massively parallel computers. Meteor. Z., 10, 363–372, doi:10.1127/0941-2948/2001/0010-0363.

    • Search Google Scholar
    • Export Citation

  • Raupach, M. R., 1981: Conditional statistics of Reynolds stress in rough-wall and smooth-wall turbulent boundary layers. J. Fluid Mech., 108, 363–382, doi:10.1017/S0022112081002164.

    • Search Google Scholar
    • Export Citation

  • Sullivan, P. P., C.-H. Moeng, B. Stevens, D. H. Lenschow, and S. D. Mayor, 1998: Structure of the entrainment zone capping the convective atmospheric boundary layer. J. Atmos. Sci., 55, 3042–3064, doi:10.1175/1520-0469(1998)055<3042:SOTEZC>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Sykes, R. I., and D. S. Henn, 1989: Large-eddy simulation of turbulent sheared convection. J. Atmos. Sci., 46, 1106–1118, doi:10.1175/1520-0469(1989)046<1106:LESOTS>2.0.CO;2.

    • Search Google Scholar
    • Export Citation

  • Watanabe, T., 2004: Large-eddy simulation of coherent turbulence structures associated with scalar ramps over plant canopies. Bound.-Layer Meteor., 112, 307–341, doi:10.1023/B:BOUN.0000027912.84492.54.

    • Search Google Scholar
    • Export Citation

  • Xie, Z.-T., and I. P. Castro, 2006: LES and RANS for turbulent flow over arrays of wall-mounted obstacles. Flow, Turbul. Combust., 76, 291–312, doi:10.1007/s10494-006-9018-6.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 617 226 93
PDF Downloads 415 82 2