Boundary-Layer Meteorology

, Volume 110, Issue 3, pp 455–470 | Cite as

Local Initiation of Deep Convection on the Canadian Prairie Provinces

  • John M. Hanesiak
  • Richard L. Raddatz
  • Scott Lobban
Article

Abstract

Our study found that local mesoscale circulations associated with highlandareas, and transient evapotranspiration discontinuities, are likely to influencethe timing and location of the initiation of deep convection across the Canadianprairie provinces when synoptic-scale forcing is weak (e.g., weak low level windsand no frontal boundaries). The cumulus congestus and cumulonimbus clouds thatformed over the highland areas were initiated by anabatic wind induced mesoscalecirculations. These deep convective clouds generally formed relatively early in theday (about 1030 Central Standard Time (CST)). In the relatively flat cropped grasslandregion, transient evapotranspiration gradients influenced the location of deep convectioninitiation, and the average soil moisture in the root zone had a direct impact on theirtiming. As root zone soil moisture declined from greater than 70% to less than 30%,convection initiation was delayed from about 0930 to 1630 CST. Cumulus congestusand cumulonimbus clouds that formed over the ephemeral evapotranspiration gradientswere initiated by land-land circulations. The study has improved the understanding ofthe influence of local surface forcing on the development of deep convective cloud onthe Canadian prairie provinces. The identification of areas where deep convection islikely to be initiated with weak synoptic forcing will also aid in the forecasting ofthunderstorms in this region.

Convection Evapotranspiration Surface-atmosphere interactions 

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References

  1. Angevine, W. M., Baltink, H. K., and Bosveld, F. C.: 2001, 'Observations of the Morning Transition of the Convective Boundary Layer', Boundary-Layer Meteorol. 101, 209–227.Google Scholar
  2. Arora, V.: 2002, 'Modeling Vegetation as a Dynamic Component in Soil-Vegetation-Atmosphere Transfer Schemes and Hydrological Models', Rev. Geophys. 40, 1–26.Google Scholar
  3. Basara, J. B and Crawford, K. C.: 2002, 'Linear Relationships between Root-Zone Soil Moisture and Atmospheric Processes in the Planetary Boundary Layer', J. Geophys. Res. 107(D15), 2–18.Google Scholar
  4. Betts, A. K.: 2000, 'Idealized Model for Equilibrium Boundary Layer over Land', J. Hydrometeorol. 1, 507–523.Google Scholar
  5. Bosilovich, M. G. and Schubert, S. D.: 2002, 'Water Vapor Tracers as Diagnostics of the Regional Hydrologic Cycle', J. Hydrometeorol. 3, 149–165.Google Scholar
  6. Canada Committee on Ecological Land Classification: 1989, Eco-Climatic Regions of Canada, Ecological Land Classification, Series No. 23, Environment Canada, Ottawa, ON, 118 pp.Google Scholar
  7. Emori, S.: 1998, 'The Interaction of Cumulus Convection with Soil Moisture Distribution: An Idealized Simulation', J. Geophys. Res. 103(D8), 8873–8884.Google Scholar
  8. Hadfield, M. G., Cotton, W. R., and Pielke, R. A.: 1991, 'Large Eddie Simulation of Thermally Forced Circulations in the Convective Boundary Layer. Part I: A Small-Scale Circulation with Zero Wind Speed', Boundary-Layer Meteorol. 57, 79–114.Google Scholar
  9. Lee, S-H. and Kimura, F.: 2001, 'Comparative Studies in the Local Circulations Induced by Land-Use and Topography', Boundary-Layer Meteorol. 101, 157–182.Google Scholar
  10. Lemone, M. A., Grossman, R. L., McMillen, R. T., Liou, K.-N., Ou, S. C., McKeen, S., Angevine, W., Ikeda, K., and Chen, F.: 2002, 'CASES-97: Late Morning Warming and Moistening of the Convective Boundary Layer over the Walnut River Watershed', Boundary-Layer Meteorol. 104, 1–52.Google Scholar
  11. Mohr, I. K., Baker, R. D., Tao, W-K., and Famiglietti, J. S.: 2003, 'The Sensitivity of West African Convective Line Water Budgets to Land Cover', J. Hydometeorol. 4, 62–76.Google Scholar
  12. Pielke, R. A.: 2001, 'Influence of the Spatial Distribution of Vegetation and Soils on the Prediction of Cumulus Convective Rainfall', Rev. Geophys. 39, 151–177.Google Scholar
  13. Pielke, R. A. and Zeng, X.: 1989, 'Influence on Severe Storm Development of Irrigated Land', Nat. Wea. Digest. 14, 16–17.Google Scholar
  14. Pielke, Sr., R. A., Avissar, R., Raupach, M., Dolman, A. J., Zeng, X., and Denning, S.: 1998, 'Interactions Between the Atmosphere and Terrestrial Ecosystems: Influence on Weather and Climate', Global Change Biol. 4, 461–475.Google Scholar
  15. Pietroniro, A., Soulis, E. D., Snelgrove, K. R., and Kouwen, N.: 2001, 'A Framework for Coupling Atmospheric and Hydrological Models', in A. J. Dolman, J. W. Pomeroy, T. Oki, and A. Hall (eds.), Soil-Vegetation Atmosphere Transfer Schemes and Large-Scale Hydrological Models, Proceedings of the Maastricht Symposium S5, July 2001, IAHS Publ. No. 270, pp. 27–34.Google Scholar
  16. Rabin, R. M., Stadler, S., Wetzel, P. J., Stensrud, D. J., and Gregory, M.: 1990, 'Observed Effects of Landscape Variability on Convective Clouds', Bull. Amer. Meteorol. Soc. 71, 272–280.Google Scholar
  17. Raddatz, R. L.: 1993, 'Prairie Agroclimate Boundary-Layer Model: A Simulation of the Atmosphere/Crop-Soil Interface', Atmos-Ocean 31, 399–419.Google Scholar
  18. Raddatz, R. L.: 1998, 'Anthropogenic Vegetation Transformation and the Potential for Deep Convection on the Canadian Prairies', Can. J. Soil Sci. 78, 656–666.Google Scholar
  19. Raddatz, R. L.: 2000, 'Summer Rainfall Recycling for an Agricultural Region of the Canadian Prairies', Can. J. Soil Sci. 80, 367–373.Google Scholar
  20. Raddatz, R. L.: 2003, 'Aridity and the Potential Physiological Response of C3 Crops to Doubled Atmospheric CO2: A Simple Demonstration of the Sensitivity on the Canadian Prairies', Boundary-Layer Meteorol. 107, 483–496.Google Scholar
  21. Raddatz, R. L. and Cummine, J. D.: 2003, 'Inter-Annual Variability of Moisture Flux from the Prairie Agro-Ecosystem: Impact of Crop Phenology on the Seasonal Pattern of Tornado Days', Boundary-Layer Meteorol. 106, 283–295.Google Scholar
  22. Raddatz, R. L. and Khandekar, M. L.: 1977, 'Numerical Simulation of Cold Easterly Circulations over the Canadian Western Plains Using a Mesoscale Boundary-Layer Model', Boundary-Layer Meteorol. 11, 307–327.Google Scholar
  23. Raddatz, R. L., Ash, G. H. B., Shaykewich, C. F., Roberge, K. A., and Graham, J. L.: 1996, 'First and Second Generation Agrometeorological Models for the Prairies and Simulated Water-Demand for Potatoes', Can. J. Soil Sci. 76, 297–305.Google Scholar
  24. Segal, M., Arritt, W., and Clark, C.: 1995, 'Scaling Evaluation of the Effect of Surface Characteristics on the Potential for Deep Convection over Uniform Terrain', Mon. Wea. Rev. 123, 383–400.Google Scholar
  25. Segal, M., Avissar, R., McCumber, M. C., and Pielke, R. A.: 1988, 'Evaluation of Vegetation Effects on the Generation and Modification of Mesoscale Circulation', J. Atmos. Sci. 45, 2268–2292.Google Scholar
  26. Tian, W-S. and Parker, D. J.: 2002, 'Two-Dimensional Simulation of Orographic Effects on Boundary-Layer Convection', Quart. J. Roy. Meteorol. Soc. 128, 1929–1952.Google Scholar
  27. Zhu, P. and Albrecht, B.: 2002, 'A Theoretical and Observational Analysis on the Formation of Fair-Weather Cumuli', J. Atmos. Sci. 59, 1983–2005.Google Scholar

Copyright information

© Kluwer Academic Publishers 2004

Authors and Affiliations

  • John M. Hanesiak
    • 1
  • Richard L. Raddatz
    • 2
  • Scott Lobban
    • 1
  1. 1.Centre for Earth Observation Science (CEOS)University of ManitobaWinnipegCanada
  2. 2.Atmospheric & Hydrological Sciences DivisionMeteorological Service of Canada, Prairie and Northern Region, Environment CanadaWinnipegCanada

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