• Arakawa, A., and W. H. Schubert, 1974: Interaction of cumulus cloud ensemble with the large-scale environment. Part I. J. Atmos. Sci., 31 , 674701.

    • Search Google Scholar
    • Export Citation
  • Arritt, R. W., T. D. Rink, M. Segal, D. P. Todey, C. A. Clark, M. J. Mitchell, and K. M. Labas, 1997: The Great Plains low-level jet during the warm season of 1993. Mon. Wea. Rev., 125 , 21762192.

    • Search Google Scholar
    • Export Citation
  • Becker, A., H. Kraus, and C. M. Ewenz, 1997: On the variety of cold fronts: Two-dimensional numerical simulations. Beitr. Phys. Atmos., 70 , 265283.

    • Search Google Scholar
    • Export Citation
  • Briegleb, B. P., 1992: Delta-Eddington approximation for solar radiation the NCAR community climate model. J. Geophys. Res., 97 , 76037612.

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

    • Search Google Scholar
    • Export Citation
  • Dickenson, R. E., A. Henderson-Sellers, and P. J. Kennedy, 1992: Biosphere–Atmosphere Scheme (BATS) version, 1e as coupled to NCAR Community Climate Model. NCAR Tech. Note 387-STR, 72 pp. [Available from NCAR, P.O. Box 3000, Boulder, CO 80307.].

    • Search Google Scholar
    • Export Citation
  • Fritsch, J. M., R. J. Kane, and C. R. Chelius, 1986: The contribution of the mesoscale convective weather systems to the warm-season precipitation of the United States. J. Climate Appl. Meteor., 25 , 13331345.

    • Search Google Scholar
    • Export Citation
  • Giorgi, F., and X. Bi, 2000: A study of internal variability of a regional climate model. J. Geophys. Res., 105 , 2950329521.

  • Giorgi, F., M. R. Marinucci, G. T. Bates, and G. De Canio, 1993: Development of a second-generation regional climate model (RegCM2). Part II: Convective processes and assimilation of boundary conditions. Mon. Wea. Rev., 121 , 28142832.

    • Search Google Scholar
    • Export Citation
  • Giorgi, F., O. Mearns, C. Shields, and L. Mayer, 1996: A regional model study of the importance of local versus remote controls on the 1988 drought and the 1993 flood over the central United States. J. Climate, 9 , 11501162.

    • Search Google Scholar
    • Export Citation
  • Grell, G. A., J. F. Dudhia, and D. R. Stauffer, 1995: A description of the fifth-generation Penn State/NCAR Mesoscale Model (MM5). NCAR Tech. Note NCAR/TN-398+IA, 107 pp. [Available from NCAR, P.O. Box 3000, Boulder, CO 80307.].

    • Search Google Scholar
    • Export Citation
  • Helfand, H. M., and S. D. Schubert, 1995: Climatology of the simulated Great Plains low-level jet and its contribution to the continental moisture budget of the United States. J. Climate, 8 , 784806.

    • Search Google Scholar
    • Export Citation
  • Higgins, R. W., J. E. Janowiak, and Y-P. Yao, 1996: A gridded hourly precipitation database for the United States (1963–1993). Climate Prediction Center Atlas, No. 1, NCEP, 47 pp. [Available from U.S. Dept. of Commerce, NOAA, Camp Springs, MD 20746.].

    • Search Google Scholar
    • Export Citation
  • Holtslag, A. A. M., E. I. F. de Bruin, and H. L. Pan, 1990: A high resolution air mass transformation model for short-range weather forecasting. Mon. Wea. Rev., 118 , 15611575.

    • Search Google Scholar
    • Export Citation
  • Koch, S. E., J. T. McQueen, and V. M. Karyampudi, 1995: A numerical study of the effects of differential cloud cover on cold frontal structure dynamics. J. Atmos. Sci., 52 , 937964.

    • Search Google Scholar
    • Export Citation
  • Koch, S. E., A. Aksakal, and J. T. McQueen, 1997: The influence of mesoscale humidity and evapotranspiration field in model forecast of cold-frontal squall line. Mon. Wea. Rev., 125 , 384409.

    • Search Google Scholar
    • Export Citation
  • Maddox, R., 1983: Large-scale meteorological conditions associated with midlatitude mesoscale convective complexes. Mon. Wea. Rev., 111 , 14751493.

    • Search Google Scholar
    • Export Citation
  • Mo., K. C., J. N. Paegle, and J. Paegle, 1995: Physical mechanisms of the 1993 floods. J. Atmos. Sci., 52 , 879895.

  • Paegle, J., K. C. Mo., and J. Nogues-Paegle, 1996: Dependence of simulated precipitation on surface evaporation during the 1993 United States summer floods. Mon. Wea. Rev., 124 , 345361.

    • Search Google Scholar
    • Export Citation
  • Pan, Z., R. W. Arritt, M. Segal, T-C. Chen, and S-P. Weng, 2000: Effects of quasi-stationary large-scale anomalies on some mesoscale features associated with the 1993 flood: A regional model simulation. J. Geophys. Res., 105 , 2955129564.

    • Search Google Scholar
    • Export Citation
  • Pan, Z., J. H. Christensen, R. W. Arritt, W. J. Gutowski Jr., E. S. Takle, and F. Otieno, 2001: Evaluation of uncertainties in regional climate change simulations. J. Geophys. Res., 106 , 1773517751.

    • Search Google Scholar
    • Export Citation
  • Segal, M., W. L. Physick, J. Heim, and R. W. Arritt, 1993: On the enhancement of cold front temperature controls by differential cloud cover. Mon. Wea. Rev., 121 , 867873.

    • Search Google Scholar
    • Export Citation
  • Trenberth, K. E., and C. J. Guillemot, 1996: Physical processes in the 1988 drought and 1993 floods in North America. J. Climate, 9 , 12881298.

    • Search Google Scholar
    • Export Citation
  • Wallace, J. M., 1975: Diurnal variations in precipitation and thunderstorm frequency over conterminous United States. Mon. Wea. Rev., 103 , 406419.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 0 0 0
PDF Downloads 0 0 0

On the Effect of Relative Timing of Diurnal and Large-Scale Forcing on Summer Extreme Rainfall Characteristics over the Central United States

View More View Less
  • 1 Agricultural Meteorology, Department of Agronomy, Iowa State University, Ames, Iowa
Restricted access

Abstract

Impacts of diurnal radiative forcing on flow and rainfall patterns during summer flood and drought conditions (1993 and 1988, respectively) in the central United States were investigated using a regional climate model. The modeling approach, which included evaluation of sensitivity to modification in the solar hour, enabled evaluation of the impact on an event-by-event basis. The effect of the solar hour forward shift of 12 h on boundary layer wind speed over north-central Texas, which is often related to rainfall in the central United States through northward moisture advection, followed almost exactly the shift in solar hour. Domain-averaged daily rainfall in the central United States simulated with 12-h solar shift frequently showed in the flood year a backward or forward time shift of ∼12 h in the timing of its peak, an increase or decrease of rainfall rate, and on a few occasions noticeable formation of short-lived rainfall events. This pattern suggests relatively high sensitivity to the timing of the diurnal radiative forcing with respect to the large-scale perturbations. In contrast, in the drought year 12-h solar shifted simulations these modifications were weaker. The climatological domain-average diurnal cycle of rainfall showed for the flood year a well-defined 12-h shift when comparing the control and perturbed simulations. In contrast, in the drought year such a shift was not well defined.

Corresponding author address: Moti Segal, Agricultural Meteorology, Department of Agronomy, Iowa State University, 3010 Agronomy, Ames, IA 50011. Email: segal@iastate.edu

Abstract

Impacts of diurnal radiative forcing on flow and rainfall patterns during summer flood and drought conditions (1993 and 1988, respectively) in the central United States were investigated using a regional climate model. The modeling approach, which included evaluation of sensitivity to modification in the solar hour, enabled evaluation of the impact on an event-by-event basis. The effect of the solar hour forward shift of 12 h on boundary layer wind speed over north-central Texas, which is often related to rainfall in the central United States through northward moisture advection, followed almost exactly the shift in solar hour. Domain-averaged daily rainfall in the central United States simulated with 12-h solar shift frequently showed in the flood year a backward or forward time shift of ∼12 h in the timing of its peak, an increase or decrease of rainfall rate, and on a few occasions noticeable formation of short-lived rainfall events. This pattern suggests relatively high sensitivity to the timing of the diurnal radiative forcing with respect to the large-scale perturbations. In contrast, in the drought year 12-h solar shifted simulations these modifications were weaker. The climatological domain-average diurnal cycle of rainfall showed for the flood year a well-defined 12-h shift when comparing the control and perturbed simulations. In contrast, in the drought year such a shift was not well defined.

Corresponding author address: Moti Segal, Agricultural Meteorology, Department of Agronomy, Iowa State University, 3010 Agronomy, Ames, IA 50011. Email: segal@iastate.edu

Save