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Morning breakup of cold pools in complex terrain

Published online by Cambridge University Press:  10 December 2008

M. PRINCEVAC  and
H. J. S. FERNANDO
M. PRINCEVAC*
Affiliation:
Department of Mechanical Engineering, University of California, Riverside, CA 92521, USA
H. J. S. FERNANDO
Affiliation:
Center for Environmental Fluid Dynamics, Department of Mechanical and Aerospace Engineering, Arizona State University, Tempe, AZ 85287–9809, USA
*
†Email address for correspondence: marko@engr.ucr.edu
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Abstract

Under fair weather conditions, local flow patterns in areas of complex topography are driven by diurnal heating and cooling. If the topography is basin-shaped, downslope flows occurring at night accumulate (pool) in the basin valley to form a stable layer of cold air. During the morning transition, this cold pool is destroyed by the onset of turbulent convection and upslope flow. A series of laboratory experiments was conducted to identify mechanisms responsible for the breakup of cold pools. An idealized V-shaped tank filled with thermally stratified water and heated with an approximately uniform bottom heat flux was used. Temperature measurements and dye visualization were used for flow diagnostics. Mechanisms of cold pool destruction were identified and placed in the context of previously proposed mechanisms. A new mechanism was identified, wherein a dominant intrusion emanating from the upslope flow plays a dynamically important role in cold pool destruction. The results are expected to help develop subgrid parameterizations for meso-scale weather forecasting models, which are notorious for giving poor predictions during the morning transition period in complex terrain.

Type
Papers
Information
Journal of Fluid Mechanics , Volume 616 , 10 December 2008 , pp. 99 - 109
Copyright
Copyright © Cambridge University Press 2008

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References

REFERENCES

Bejan, A. 2004 Convection Heat Transfer. John Wiley & Sons.Google Scholar
Chen, R. R., Berman, N. S., Boyer, D. L. & Fernando, H. J. S. 1999 Physical modeling of nocturnal drainage flow in complex terrain. Contrib. Atmos. Phys. 72, 219–242.Google Scholar
Chan, W. C. 2001 The modeling of an anabatic flow in complex terrain. MS Thesis, Arizona State University.Google Scholar
Colette, A., Chow, F. K. & Street, R. L. 2003 A numerical study of inversion-layer breakup and the effects of topographic shading in idealized valleys. J. Appl. Met. 42, 1255–1272.2.0.CO;2>CrossRefGoogle Scholar
Deardorff, J. W. & Willis, G. E. 1987 Turbulence within a baroclinic laboratory mixed layer above a sloping surface. J. Atmos. Sci. 44 (4), 772–778.2.0.CO;2>CrossRefGoogle Scholar
Fernando, H. J. S. 1987 The formation of a layered structure when a stable salinity gradient is heated from below. J. Fluid Mech. 182, 525–541.CrossRefGoogle Scholar
Hunt, J. C. R., Fernando, H. J. S. & Princevac, M. 2003 Unsteady Thermally Driven Flows on Gentle Slopes. J. Atmos. Sci. 60 (17), 2169–2182.2.0.CO;2>CrossRefGoogle Scholar
Lee, S. M., Fernando, H. J. S. & Grossman-Clarke, S. 2007 MM5-SMOKE-CMAQ as a modeling tool for 8-h ozone regulatory enforcement: application to the state of Arizona. Environ. Model. Assess. 12 (1), 63–74.CrossRefGoogle Scholar
Lee, S. M., Giori, W., Princevac, M. & Fernando, H. J. S. 2006 A new turbulent parameterization for the nocturnal PBL over complex terrain. Boundary Layer Met. 119 (1), 109–134.CrossRefGoogle Scholar
Lu, R. & Turco, R. P. 1994 Air pollutant transport in a coastal environment. Part 1: 2-D simulations of sea-breeze and mountain effects. J. Atmos. Sci. 51 (15), 2285–2308.2.0.CO;2>CrossRefGoogle Scholar
Lu, R. & Turco, R. P. 1995 Air Pollutant Transport in a Coastal Environment. Part 2: 3-Dimensional Simulations Over Los-Angeles Basin Atmos. Environ. 29 (13), 1499–1518.CrossRefGoogle Scholar
Whiteman, C. D. 1982 Breakup of temperature inversions in deep mountain valleys: Part I. Observations. J. Appl. Met. 21 (3), 270–289.2.0.CO;2>CrossRefGoogle Scholar
Whiteman, C. D. & McKee, T. B. 1982 Breakup of temperature inversions in deep mountain valleys: Part II. Thermodynamic model. J. Appl. Met. 21 (3), 290–302.2.0.CO;2>CrossRefGoogle Scholar
Whiteman, C. D. 2000 Mountain Meteorology: Fundamentals and Applications. Oxford University Press.CrossRefGoogle Scholar
Whiteman, C. D. 1990 Observations of thermally developed wind systems in mountainous terrain. In Atmospheric Processes Over Complex Terrain (ed. Blumen, W.). Meterological Monographs, vol. 23 (45), pp. 5–42. American Meteorological SocietyCrossRefGoogle Scholar