• Avissar, R., and Chen F. , 1993: Development and analysis of prognostic equations for mesoscale kinetic energy and mesoscale (subgrid scale) fluxes for large-scale atmospheric models. J. Atmos. Sci, 50 , 37513774.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Chang, J. T., and Wetzel P. J. , 1991: Effects of spatial variations of soil moisture and vegetation on the evolution of a prestorm environment—A numerical case study. Mon. Wea. Rev, 119 , 13681390.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Changnon, S. A., 2001: Thunderstorm rainfall in the conterminous United States. Bull. Amer. Meteor. Soc, 82 , 19251940.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Chen, F., and Avissar R. , 1994: The impact of land-surface wetness heterogeneity on mesoscale heat fluxes. J. Appl. Meteor, 33 , 13231340.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Dai, A., and Trenberth K. E. , 2004: The diurnal cycle and its depiction in the Community Climate System Model. J. Climate, 17 , 930951.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Dai, A., Giorgi F. , and Trenberth K. E. , 1999: Observed and model-simulated diurnal cycles of precipitation over the contiguous United States. J. Geophys. Res, 104 , 63776402.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Dalu, G. A., Pielke R. A. , Vidale P. L. , and Baldi M. , 2000: Heat transport and weakening of atmospheric stability induced by mesoscale flows. J. Geophys. Res, 105 , 93499363.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Donner, L. J., 1993: A cumulus parameterization including mass fluxes, vertical momentum dynamics, and mesoscale effects. J. Atmos. Sci, 50 , 889906.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Donner, L. J., Seman C. J. , Hemler R. S. , and Fan S. , 2001: A cumulus parameterization including mass fluxes, convective vertical velocities, and mesoscale effects: Thermodynamic and hydrological aspects in a general circulation model. J. Climate, 14 , 34443463.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Findell, K. L., and Eltahir E. A. B. , 2003a: Atmospheric controls on soil moisture–boundary layer interactions. Part I: Framework development. J. Hydrometeor, 4 , 552569.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Findell, K. L., and Eltahir E. A. B. , 2003b: Atmospheric controls on soil moisture– boundary layer interactions. Part II: Feedbacks within the continental United States. J. Hydrometeor, 4 , 570583.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Findell, K. L., and Eltahir E. A. B. , 2003c: Atmospheric controls on soil moisture– boundary layer interactions: Three-dimensional wind effects. J. Geophys. Res.,108, 8385, doi:10.1029/2001JD001515.

    • Search Google Scholar
    • Export Citation
  • Kain, J., and Fritsch J. , 1992: The role of the convective “trigger function” in numerical forecasts of mesoscale convective systems. Meteor. Atmos. Phys, 49 , 93106.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Lynn, B., Abramopoulos F. , and Avissar R. , 1995a: Using similarity theory to parameterize mesoscale heat fluxes generated by subgrid-scale landscape discontinuities in GCMs. J. Climate, 8 , 932951.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Lynn, B., Rind D. , and Avissar R. , 1995b: The importance of mesoscale circulations generated by subgrid-scale landscape heterogeneities in general circulation models. J. Climate, 8 , 191205.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Mahrt, L., 1977: Influence of low-level environment on severity of high-plains moist convection. Mon. Wea. Rev, 105 , 13151329.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Mahrt, L., and Pierce D. , 1980: Relationship of moist convection to boundary-layer properties: Application to a semiarid region. Mon. Wea. Rev, 108 , 18101815.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Pielke, R. A., Dalu G. A. , Snook J. S. , Lee T. J. , and Kittel T. G. F. , 1991: Nonlinear influence of mesoscale land use on weather and climate. J. Climate, 4 , 10531069.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Pielke, R. A., Avissar R. , Raupach M. , Dolman A. J. , Zeng X. , and Denning A. S. , 1998: Interactions between the atmosphere and terrestrial ecosystems: Influence on weather and climate. Global Change Biol, 4 , 461475.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Pincus, R., and Klein S. A. , 2000: Unresolved spatial variability and process rates in large scale models. J. Geophys. Res, 105 , 2705927065.

  • Randall, D., Khairoutdinov M. , Arakawa A. , and Grabowski W. , 2003: Breaking the cloud parameterization deadlock. Bull. Amer. Meteor. Soc, 84 , 15471564.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Taylor, C. M., and Lebel T. , 1998: Observational evidence of persistent convective-scale rainfall patterns. Mon. Wea. Rev, 126 , 15971607.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Taylor, C. M., Said F. , and Lebel T. , 1997: Interactions between the land surface and mesoscale rainfall variability during HAPEX-Sahel. Mon. Wea. Rev, 125 , 22112227.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wang, J., Bras R. , and Eltahir E. A. B. , 1998: Numerical simulation of nonlinear mesoscale circulations induced by the thermal inhomogeneities of land surface. J. Atmos. Sci, 55 , 447464.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Weaver, C. P., 2004: Coupling between large-scale atmospheric processes and mesoscale land–atmosphere interactions in the U.S. Southern Great Plains during summer. Part I: Case studies. J. Hydrometeor, 5 , 12231246.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Weaver, C. P., and Avissar R. , 2001: Atmospheric disturbances caused by human modification of the landscape. Bull. Amer. Meteor. Soc, 82 , 269281.

    • Crossref
    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 90 41 0
PDF Downloads 43 17 0

Coupling between Large-Scale Atmospheric Processes and Mesoscale Land–Atmosphere Interactions in the U.S. Southern Great Plains during Summer. Part II: Mean Impacts of the Mesoscale

View More View Less
  • 1 Center for Environmental Prediction, Department of Environmental Sciences, Rutgers–The State University of New Jersey, New Brunswick, New Jersey
Restricted access

Abstract

This is Part II of a two-part study of mesoscale land–atmosphere interactions in the summertime U.S. Southern Great Plains. Part I focused on case studies drawn from monthlong (July 1995–97), high-resolution Regional Atmospheric Modeling System (RAMS) simulations carried out to investigate these interactions. These case studies were chosen to highlight key features of the lower-tropospheric mesoscale circulations that frequently arise in this region and season due to mesoscale heterogeneity in the surface fluxes. In this paper, Part II, the RAMS-simulated mesoscale dynamical processes described in the Part I case studies are examined from a domain-averaged perspective to assess their importance in the overall regional hydrometeorology. The spatial statistics of key simulated mesoscale variables—for example, vertical velocity and the vertical flux of water vapor—are quantified here. Composite averages of the mesoscale and large-scale-mean variables over different meteorological or dynamical regimes are also calculated. The main finding is that, during dry periods, or similarly, during periods characterized by large-scale-mean subsidence, the characteristic signature of surface-heterogeneity-forced mesoscale circulations, including enhanced vertical motion variability and enhanced mesoscale fluxes in the lowest few kilometers of the atmosphere, consistently emerges. Furthermore, the impact of these mesoscale circulations is nonnegligible compared to the large-scale dynamics at domain-averaged (200 km × 200 km) spatial scales and weekly to monthly time scales. These findings support the hypothesis that the land– atmosphere interactions associated with mesoscale surface heterogeneity can provide pathways whereby diurnal, mesoscale atmospheric processes can scale up to have more general impacts at larger spatial scales and over longer time scales.

Corresponding author address: Christopher P. Weaver, Center for Environmental Prediction, Department of Environmental Sciences, Rutgers–The State University of New Jersey, 14 College Farm Road, New Brunswick, NJ 08901-8551. Email: weaver@cep.rutgers.edu

Abstract

This is Part II of a two-part study of mesoscale land–atmosphere interactions in the summertime U.S. Southern Great Plains. Part I focused on case studies drawn from monthlong (July 1995–97), high-resolution Regional Atmospheric Modeling System (RAMS) simulations carried out to investigate these interactions. These case studies were chosen to highlight key features of the lower-tropospheric mesoscale circulations that frequently arise in this region and season due to mesoscale heterogeneity in the surface fluxes. In this paper, Part II, the RAMS-simulated mesoscale dynamical processes described in the Part I case studies are examined from a domain-averaged perspective to assess their importance in the overall regional hydrometeorology. The spatial statistics of key simulated mesoscale variables—for example, vertical velocity and the vertical flux of water vapor—are quantified here. Composite averages of the mesoscale and large-scale-mean variables over different meteorological or dynamical regimes are also calculated. The main finding is that, during dry periods, or similarly, during periods characterized by large-scale-mean subsidence, the characteristic signature of surface-heterogeneity-forced mesoscale circulations, including enhanced vertical motion variability and enhanced mesoscale fluxes in the lowest few kilometers of the atmosphere, consistently emerges. Furthermore, the impact of these mesoscale circulations is nonnegligible compared to the large-scale dynamics at domain-averaged (200 km × 200 km) spatial scales and weekly to monthly time scales. These findings support the hypothesis that the land– atmosphere interactions associated with mesoscale surface heterogeneity can provide pathways whereby diurnal, mesoscale atmospheric processes can scale up to have more general impacts at larger spatial scales and over longer time scales.

Corresponding author address: Christopher P. Weaver, Center for Environmental Prediction, Department of Environmental Sciences, Rutgers–The State University of New Jersey, 14 College Farm Road, New Brunswick, NJ 08901-8551. Email: weaver@cep.rutgers.edu

Save