Article Type:
Research Article

Numerical Simulations of Low-CAPE Flows over a Mountain Ridge

Mario Marcello Miglietta ISAC-CNR, Padua/Lecce, Italy

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Richard Rotunno NCAR,* Boulder, Colorado

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Print Publication:
01 Jul 2010
DOI:
https://doi.org/10.1175/2010JAS3378.1
Page(s):
2391–2401
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Abstract

In a recent study, the authors performed numerical simulations of conditionally unstable flows past a mesoscale mountain ridge in order to investigate the statistically stationary features of the solution precipitation characteristics for intermediate-to-high values of convective available potential energy (CAPE). That study proposed a functional dependence of the rain rate on three parameters, related respectively to the triggering and the orographic forcing of convection and to the ratio of the advective to convective time scales. The present study extends that analysis to cover larger regions of the parameter space, including experiments corresponding to a wider range of CAPE. It is found here that the low-CAPE, moderate-wind experiments do not fit the functional dependence for rain rate amount and location proposed in the authors’ previous study. The analysis of the present solutions suggests that two additional nondimensional parameters should be taken into account.

Corresponding author address: Mario Marcello Miglietta, CNR-ISAC, corso Stati Uniti 4, 35127 Padua, Italy. Email: m.miglietta@isac.cnr.it

Abstract

In a recent study, the authors performed numerical simulations of conditionally unstable flows past a mesoscale mountain ridge in order to investigate the statistically stationary features of the solution precipitation characteristics for intermediate-to-high values of convective available potential energy (CAPE). That study proposed a functional dependence of the rain rate on three parameters, related respectively to the triggering and the orographic forcing of convection and to the ratio of the advective to convective time scales. The present study extends that analysis to cover larger regions of the parameter space, including experiments corresponding to a wider range of CAPE. It is found here that the low-CAPE, moderate-wind experiments do not fit the functional dependence for rain rate amount and location proposed in the authors’ previous study. The analysis of the present solutions suggests that two additional nondimensional parameters should be taken into account.

Corresponding author address: Mario Marcello Miglietta, CNR-ISAC, corso Stati Uniti 4, 35127 Padua, Italy. Email: m.miglietta@isac.cnr.it

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  • Bryan, G. H., and J. M. Fritsch, 2002: A benchmark simulation for moist nonhydrostatic models. Mon. Wea. Rev., 130 , 2917–2928.

  • Bryan, G. H., J. C. Wyngaard, and J. M. Fritsch, 2003: Resolution requirements for the simulation of deep moist convection. Mon. Wea. Rev., 131 , 2394–2416.

    • Search Google Scholar
    • Export Citation

  • Caracena, F. R., A. Maddox, L. R. Hoxit, and C. F. Chappell, 1979: Mesoanalysis of the Big Thompson storm. Mon. Wea. Rev., 107 , 1–17.

  • Chen, S-H., and Y-L. Lin, 2005: Effects of moist Froude number and CAPE on a conditionally unstable flow over a mesoscale mountain ridge. J. Atmos. Sci., 62 , 331–350.

    • Search Google Scholar
    • Export Citation

  • Chu, C-M., and Y-L. Lin, 2000: Effects of orography on the generation and propagation of mesoscale convective systems in a two-dimensional conditionally unstable flow. J. Atmos. Sci., 57 , 3817–3837.

    • Search Google Scholar
    • Export Citation

  • Davolio, S., A. Buzzi, and P. Malguzzi, 2006: Orographic influence on deep convection: Case study and sensitivity experiments. Meteor. Z., 15 , 215–223.

    • Search Google Scholar
    • Export Citation

  • Delrieu, G., and Coauthors, 2005: The catastrophic flash-flood event of 8–9 September 2002 in the Gard region, France: A first case study for the Cévennes–Vivarais Mediterranean Hydrometeorological Observatory. J. Hydrometeor., 6 , 34–52.

    • Search Google Scholar
    • Export Citation

  • Gilmore, M., and L. J. Wicker, 1998: The influence of midtropospheric dryness on supercell morphology and evolution. Mon. Wea. Rev., 126 , 943–958.

    • Search Google Scholar
    • Export Citation

  • Jiang, Q., 2003: Moist dynamics and orographic precipitation. Tellus, 55A , 301–316.

  • Kirshbaum, D. J., G. H. Bryan, R. Rotunno, and D. R. Durran, 2007: The triggering of orographic rainbands by small-scale topography. J. Atmos. Sci., 64 , 1530–1549.

    • Search Google Scholar
    • Export Citation

  • Lin, Y-L., S. Chiao, T-A. Wang, M. L. Kaplan, and R. P. Weglarz, 2001: Some common ingredients for heavy orographic rainfall. Wea. Forecasting, 16 , 633–660.

    • Search Google Scholar
    • Export Citation

  • Lyman, R. E., T. A. Schroeder, and G. M. Barnes, 2005: The heavy rain event of 29 October 2000 in Hana, Maui. Wea. Forecasting, 20 , 397–414.

    • Search Google Scholar
    • Export Citation

  • Miglietta, M. M., and A. Buzzi, 2001: A numerical study of moist stratified flows over isolated topography. Tellus, 53A , 481–499.

  • Miglietta, M. M., and R. Rotunno, 2005: Simulations of moist nearly neutral flow over a ridge. J. Atmos. Sci., 62 , 1410–1427.

  • Miglietta, M. M., and R. Rotunno, 2006: Further results on moist nearly neutral flow over a ridge. J. Atmos. Sci., 63 , 2881–2897.

  • Miglietta, M. M., and R. Rotunno, 2009: Numerical simulations of conditionally unstable flows over a ridge. J. Atmos. Sci., 66 , 1865–1885.

    • Search Google Scholar
    • Export Citation

  • Pontrelli, M. D., G. H. Bryan, and J. M. Fritsch, 1999: The Madison County, Virginia, flash flood of 27 June 1995. Wea. Forecasting, 14 , 384–404.

    • Search Google Scholar
    • Export Citation

  • Reeves, H. D., and R. Rotunno, 2008: Orographic flow response to variations in upstream humidity. J. Atmos. Sci., 66 , 3557–3570.

  • Richard, E., A. Buzzi, and G. Zängl, 2007: Quantitative precipitation forecasting in the Alps: The advances achieved by the Mesoscale Alpine Programme. Quart. J. Roy. Meteor. Soc., 133 , 831–846.

    • Search Google Scholar
    • Export Citation

  • Romero, R., C. A. Doswell III, and C. Ramis, 2000: Mesoscale numerical study of two cases of long-lived quasi-stationary convective systems over eastern Spain. Mon. Wea. Rev., 128 , 3731–3751.

    • Search Google Scholar
    • Export Citation

  • Rotunno, R., and R. Ferretti, 2001: Mechanisms of intense Alpine rainfall. J. Atmos. Sci., 58 , 1732–1749.

  • Schroeder, T. A., 1977: Meteorological analysis of an Oahu flood. Mon. Wea. Rev., 105 , 458–468.

  • Senesi, S., P. Bougeault, J-L. Chèze, P. Cosentino, and R-M. Thepenier, 1996: The Vaison-La-Romaine flash flood: Mesoscale analysis and predictability issues. Wea. Forecasting, 11 , 417–442.

    • Search Google Scholar
    • Export Citation

  • Stein, J., 2004: Exploration of some convective regimes over Alpine orography. Quart. J. Roy. Meteor. Soc., 130 , 481–502.

  • Wang, J-J., R. M. Rauber, H. T. Ochs III, and R. E. Carbone, 2000: The effects of the island of Hawaii on offshore rainband evolution. Mon. Wea. Rev., 128 , 1052–1069.

    • Search Google Scholar
    • Export Citation

  • Weisman, M. L., and J. B. Klemp, 1982: The dependence of numerically simulated convective storms on vertical wind shear and buoyancy. Mon. Wea. Rev., 110 , 504–520.

    • Search Google Scholar
    • Export Citation

  • Yoshizaki, M., and Y. Ogura, 1988: Two- and three-dimensional modeling studies of the Big Thompson storm. J. Atmos. Sci., 45 , 3700–3722.

    • Search Google Scholar
    • Export Citation
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