A Numerical Study of the Thermally Driven Plain-to-Basin Wind over Idealized Basin Topographies

Stephan F. J. de Wekker Pacific Northwest National Laboratory, Richland, Washington

Search for other papers by Stephan F. J. de Wekker in
Current site
Google Scholar
PubMed
Close
,
Shiyuan Zhong Pacific Northwest National Laboratory, Richland, Washington

Search for other papers by Shiyuan Zhong in
Current site
Google Scholar
PubMed
Close
,
Jerome D. Fast Pacific Northwest National Laboratory, Richland, Washington

Search for other papers by Jerome D. Fast in
Current site
Google Scholar
PubMed
Close
, and
C. David Whiteman Pacific Northwest National Laboratory, Richland, Washington

Search for other papers by C. David Whiteman in
Current site
Google Scholar
PubMed
Close
Restricted access

Abstract

Numerical experiments have been carried out with a two-dimensional nonhydrostatic mesoscale model to investigate the diurnal temperature range in a basin and the thermally driven plain-to-basin winds. Under clear-sky conditions, the diurnal temperature range in a basin is larger than over the surrounding plains due to a combination of larger turbulent sensible heat fluxes over the sidewalls and a volume effect in which energy fluxes are distributed through the smaller basin atmosphere. Around sunset, a thermally driven plain-to-basin flow develops, transporting air from the plains into the basin. Characteristics of this plain-to-basin wind are described for idealized basins bounded by sinusoidal mountains and the circumstances under which such winds might or might not occur are considered. In contrast with a previous numerical study, it is found that the height of the mixed layer over the plains relative to the mountain height is not a critical factor governing the occurrence or nonoccurrence of a plain-to-basin wind. The critical factor is the horizontal temperature gradient above mountain height created by a larger daytime heating rate over the basin topography than over the plains. Subsidence and turbulent heat flux divergence play important roles in this heating above mountain height.

* Current affiliation: Atmospheric Science Programme, Department of Geography, University of British Columbia, Vancouver, British Columbia, Canada.

Corresponding author address: Stephan F. J. de Wekker, Atmospheric Science Programme, Department of Geography, University of British Columbia, Vancouver, BC V6T 1Z2, Canada.

dewekker@geog.ubc.ca

Abstract

Numerical experiments have been carried out with a two-dimensional nonhydrostatic mesoscale model to investigate the diurnal temperature range in a basin and the thermally driven plain-to-basin winds. Under clear-sky conditions, the diurnal temperature range in a basin is larger than over the surrounding plains due to a combination of larger turbulent sensible heat fluxes over the sidewalls and a volume effect in which energy fluxes are distributed through the smaller basin atmosphere. Around sunset, a thermally driven plain-to-basin flow develops, transporting air from the plains into the basin. Characteristics of this plain-to-basin wind are described for idealized basins bounded by sinusoidal mountains and the circumstances under which such winds might or might not occur are considered. In contrast with a previous numerical study, it is found that the height of the mixed layer over the plains relative to the mountain height is not a critical factor governing the occurrence or nonoccurrence of a plain-to-basin wind. The critical factor is the horizontal temperature gradient above mountain height created by a larger daytime heating rate over the basin topography than over the plains. Subsidence and turbulent heat flux divergence play important roles in this heating above mountain height.

* Current affiliation: Atmospheric Science Programme, Department of Geography, University of British Columbia, Vancouver, British Columbia, Canada.

Corresponding author address: Stephan F. J. de Wekker, Atmospheric Science Programme, Department of Geography, University of British Columbia, Vancouver, BC V6T 1Z2, Canada.

dewekker@geog.ubc.ca

Save
  • Benjamin, S. G., 1986: Some effects of surface heating and topography on the regional severe storm environment. Part II: Two-dimensional idealized experiments. Mon. Wea. Rev.,114, 330–343.

  • Bossert, J. E., 1997: An investigation of flow regimes affecting the Mexico City region. J. Appl. Meteor.,36, 119–140.

  • ——, and W. R. Cotton, 1994: Regional-scale flows in mountainous terrain. Part I: A numerical and observational comparison. Mon. Wea. Rev.,122, 1449–1471.

  • Burger, A., and E. Ekhart, 1937: Über die tägliche Zirkulation der Atmosphäre im Bereich der Alpen (On the diurnal circulation of the atmosphere in the region of the Alps). Gerlands Beitr. Geophys.,49, 341–367.

  • Chen, C., and W. R. Cotton, 1983: A one-dimensional simulation of the stratocumulus-capped mixed layer. Bound.-Layer Meteor.,25, 289–321.

  • de Wekker, S. F. J., 1995: The behaviour of the convective boundary layer height over orographically complex terrain. M.S. thesis, Institute for Meteorology and Climate Research, University of Karlsruhe, Dept. of Meteorology, Wageningen Agricultural University, 74 pp.

  • Doran, J. C., and S. Zhong, 1994: Regional drainage flows in the Pacific Northwest. Mon. Wea. Rev.,122, 1158–1167.

  • Fast, J. D., 1995: Mesoscale modeling and four-dimensional data assimilation in areas of highly complex terrain. J. Appl. Meteor.,34, 2762–2782.

  • ——, S. Zhong, and C. D. Whiteman, 1996: Boundary-layer evolution within a canyonland basin: Part II: Numerical simulations of nocturnal flows and heat budgets. J. Appl. Meteor.,35, 2162–2178.

  • Jackson, P. L., and D. G. Steyn, 1994: Gap winds in a fjord. Part I:Observations and numerical simulation. Mon. Wea. Rev.,122, 2645–2665.

  • Kimura, F., and T. Kuwagata, 1993: Thermally induced wind passing from plain to basin over a mountain range. J. Appl. Meteor.,32, 1538–1547.

  • King, C. W., 1996: A climatology of thermally forced circulations in oppositely oriented airsheds along the Continental Divide in Colorado. Ph.D. dissertation, University of Colorado, 199 pp.

  • Kleinschmidt, E., 1922: Der tägliche Gang des Windes in der freien Atmosphäre und auf Berggipfeln (The diurnal course of the wind in the free atmosphere and on mountain tops). Beitr. Phys. Atmos.,10, 1–15.

  • Klemp, J. B., and R. B. Wilhelmson, 1978a: The simulation of three-dimensional convective storm dynamics. J. Atmos. Sci.,35, 1070–1096.

  • ——, and ——, 1978b: Simulations of right- and left-moving storms produced through storm splitting. J. Atmos. Sci.,35, 1097–1110.

  • Kondo, J., T. Kuwagata, and S. Haginoya, 1989: Heat budget analysis of nocturnal cooling and daytime heating in a basin. J. Atmos. Sci.,46, 2917–2933.

  • Kurita, H., H. Ueda, and S. Mitsumoto, 1990: Combination of local wind systems under light gradient wind conditions and its contribution to the long-range transport of air pollutants. J. Appl. Meteor.,29, 331–348.

  • Kuwagata, T., and F. Kimura, 1995: Daytime boundary layer evolution in a deep valley. Part I: Observations in the Ina Valley. J. Appl. Meteor.,34, 1082–1091.

  • Louis, J. F., 1979: A parametric model of vertical eddy fluxes in the atmosphere. Bound.-Layer Meteor.,17, 187–202.

  • Lu, R., and P. Turco, 1994: Air pollutant transport in a coastal environment. Part I: Two-dimensional simulations of sea-breeze and mountain effects. J. Atmos. Sci.,51, 2285–2308.

  • Mahrer, Y., and R. A. Pielke, 1977: A numerical study of the airflow over irregular terrain. Beitr. Phys. Atmos.,50, 98–113.

  • Maki, M., T. Harimaya, and K. Kikuchi, 1986: Heat budget studies on nocturnal cooling in a basin. J. Meteor. Soc. Japan,64, 727–740.

  • Mannouji, N., 1982: A numerical experiment on the mountain and valley winds. J. Meteor. Soc. Japan,60, 1085–1105.

  • Mannstein, H., 1988: The spatial variation of sensible heat flux in the Alps from satellite data. Proc. of Eighth EARSeL Symp., Capri, Italy, 356–367.

  • McKee, T. B., and R. D. O’Neal, 1989: The role of valley geometry and energy budget in the formation of nocturnal valley winds. J. Appl. Meteor.,28, 445–456.

  • Ookouchi, Y., M. Segal, R. C. Kessler, and R. A. Pielke, 1984: Evaluation of soil moisture effects on the generation and modification of mesoscale circulations. Mon. Wea. Rev.,112, 2281–2292.

  • Pielke, R. A., and Coauthors, 1992: A comprehensive meteorological modeling system—RAMS. Meteor. Atmos. Phys.,49, 69–91.

  • Reiter, E. R., and M. Tang, 1984: Plateau effects on diurnal circulation patterns. Mon. Wea. Rev.,112, 638–651.

  • Staley, D. O., 1959: Some observations of surface-wind oscillations in a heated basin. J. Meteor.,16, 364–370.

  • Steinacker, R., 1984: Area–height distribution of a valley and its relation to the valley wind. Contrib. Atmos. Phys.,57, 64–71.

  • Toth, J. J., and R. H. Johnson, 1985: Summer surface flow characteristics over northeast Colorado. Mon. Wea. Rev.,113, 1458–1469.

  • Tyson, P. D., and R. A. Preston-Whyte, 1972: Observations of regional topographically induced wind systems in Natal. J. Appl. Meteor.,11, 643–650.

  • Wagner, A., 1932: Der tägliche Luftdruck- und Temperaturgang in der freien Atmosphäre und in Gebirgstälern (The diurnal course of pressure and temperature in the free atmosphere and in mountain valleys). Gerlands Beitr. Geophys.,37, 315–344.

  • ——, 1938: Theorie und Beobachtung der periodischen Gebirgswinde (Theory and observation of periodic mountain winds). Gerlands Beitr. Geophys.,52, 408–449.

  • White, A. B., and C. W. King, 1997: A comparison of mixing depths observed over horizontally inhomogeneous terrain. EURASAP Workshop on Determination of Mixing Height, Roskilde, Denmark, 123–126.

  • Whiteman, C. D., 1982: Breakup of temperature inversions in deep mountain valleys: Part I: Observations. J. Appl. Meteor.,21, 270–289.

  • ——, 1990: Observations of thermally developed wind systems in mountainous terrain. Atmospheric Processes Over Complex Terrain, Meteor. Monogr., No. 45, Amer. Meteor. Soc., 5–42.

  • ——, K. J. Allwine, L. J. Fritschen, M. M. Orgill, and J. R. Simpson, 1989: Deep valley radiation and surface energy budget microclimates. Part II: Energy budget. J. Appl. Meteor.,28, 427–437.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 353 83 17
PDF Downloads 158 63 15