• Baker, R. D., , Lynn B. H. , , Boone A. , , Tao W-K. , , and Simpson J. , 2001: The influence of soil moisture, coastline curvature, and land-breeze circulations on sea-breeze initiated precipitation. J. Hydrometeor., 2 , 193211.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Betts, A. K., , and Ball J. H. , 1995: The FIFE surface diurnal cycle climate. J. Geophys. Res., 100 , 2567925693.

  • Betts, A. K., , and Ball J. H. , 1998: FIFE surface climate and site-average dataset 1987–89. J. Atmos. Sci., 55 , 10911108.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Brubaker, K. L., , Entekhabi D. , , and Eagleson P. S. , 1993: Estimation of continental precipitation recycling. J. Climate, 6 , 10771089.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Caniaux, G., , Redelsperger J-L. , , and Lafore J-P. , 1994: A numerical study of the stratiform region of a fast-moving convective line. Part I: General description and water and heat budgets. J. Atmos. Sci., 51 , 20462074.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Chalon, J. P., , Jaubert G. , , Roux F. , , and Lafore J. P. , 1988: The West African convective line observed on 23 June during COPT81: Mesoscale structure and transports. J. Atmos. Sci., 45 , 27442763.

    • Search Google Scholar
    • Export Citation
  • Chang, C-Y., , and Yoshizaki M. , 1993: Three-dimensional modeling study of convective lines observed in COPT81. J. Atmos. Sci., 50 , 161183.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Crook, N. A., 1996: Sensitivity of moist convection forced by boundary layer processes to low-level thermodynamic fields. Mon. Wea. Rev., 124 , 17671786.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Dudhia, J., , Moncrieff M. W. , , and So D. W. K. , 1987: The two-dimensional dynamics of West African convective lines. Quart. J. Roy. Meteor. Soc., 113 , 121146.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Ferrier, B. S., , Tao W-K. , , and Simpson J. , 1996: Factors responsible for precipitation efficiencies in midlatitude and tropical convective line simulations. Mon. Wea. Rev., 124 , 21002125.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Grabowski, W. W., , Wu X. , , Moncrieff M. W. , , and Hall W. D. , 1998: Cloud-resolving modeling of cloud systems during Phase III of GATE. Part II: Effects of resolution and the third spatial dimension. J. Atmos. Sci., 55 , 32643282.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Lafore, J-P., , and Moncrieff M. W. , 1989: A numerical investigation of the organization and interaction of the convective and stratiform regions of tropical convective lines. J. Atmos. Sci., 46 , 521544.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Lin, Y-L., , Rarley R. D. , , and Orville H. D. , 1983: Bulk parameterization of the snow field in a cloud model. J. Climate Appl. Meteor., 22 , 10651092.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Liu, C., , Moncrieff M. W. , , and Zipser E. J. , 1997: Dynamical influence of microphysics in tropical convective lines: A numerical study. Mon. Wea. Rev., 125 , 21932210.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Lucas, C., , Zipser E. J. , , and Ferrier B. S. , 2000: Sensitivity of tropical West Pacific oceanic convective lines to tropospheric wind and moisture profiles. J. Atmos. Sci., 57 , 23512373.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Lynn, B. H., , Tao W-K. , , and Wetzel P. J. , 1998: A study of landscape generated deep moist convection. Mon. Wea. Rev., 126 , 928942.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Mohr, K. I., , Famiglietti J. S. , , Boone A. , , and Starks P. J. , 2000: Modeling soil moisture and surface flux variability with an untuned land surface scheme: A case study from the Southern Great Plains 1997 Hydrology Experiment. J. Hydrometeor., 1 , 154169.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Mohr, K. I., , Famiglietti J. S. , , and Boone A. , 2001: The effect of sub-grid variability of soil moisture on the simulation of mesoscale watershed hydrology: A case study from the Southern Great Plains 1997 Hydrology Experiment. Land Surface Hydrology, Meteorology and Climate: Observations and Modeling, V. Lakshmi, J. Albertson, and J. Schaake, Eds., Amer. Geophys. Union, 161–176.

    • Search Google Scholar
    • Export Citation
  • Nicholls, M. E., , Johnson R. H. , , and Cotton W. R. , 1988: The sensitivity of two-dimensional simulations of tropical convective lines to environmental profiles. J. Atmos. Sci., 45 , 36253649.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Nicholson, S. E., , Tucker C. J. , , and Ba M. B. , 1998: Desertification, drought, and surface vegetation: An example from the West African Sahel. Bull. Amer. Meteor. Soc., 79 , 815829.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Prabhakara, C., , Iacovazzi J. R. , , Weinman J. A. , , and Dalu G. , 2000: A TRMM microwave radiometer rain rate estimation method with convective and stratiform discrimination. J. Meteor. Soc. Japan, 78 , 241258.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Roux, F., 1988: The West African convective line observed on 23 June during COPT81: Kinematics and thermodynamics of the convective region. J. Atmos. Sci., 45 , 406426.

    • Search Google Scholar
    • Export Citation
  • Rutledge, S. A., , and Hobbs P. V. , 1984: The mesoscale and microscale structure and organization of clouds and precipitation in midlatitude cyclones. Part XII: A diagnostic modeling study of precipitation development in narrow cold frontal rainbands. J. Atmos. Sci., 41 , 29492972.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Tao, W-K., , and Simpson J. , 1993: Goddard Cumulus Ensemble model. Part I: Description. Terr. Atmos. Oceanic Sci., 4 , 3572.

  • Tao, W-K., , Lang S. , , Simpson J. , , Sui C-H. , , Ferrier B. , , and Chou M-D. , 1996: Mechanisms of cloud–radiation interaction in the Tropics and midlatitudes. J. Atmos. Sci., 53 , 26242651.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Tao, W-K., and Coauthors. 2002: Microphysics, radiation, and surface processes in the Goddard Cumulus Ensemble (GCE) model. Meteor. Atmos. Phys., doi: 10.1007/s00703-001-0594-7.

    • Search Google Scholar
    • Export Citation
  • Weisman, M. L., , Skamarock W. C. , , and Klemp J. B. , 1997: The resolution dependence of explicitly modeled convective systems. Mon. Wea. Rev., 125 , 527548.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wetzel, P. J., , and Boone A. , 1995: A Parameterization for Land–Atmosphere–Cloud Exchange (PLACE): Documentation and testing of a detailed process model of the partly cloudy boundary layer over heterogeneous land. J. Climate, 8 , 18101837.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Xu, K-M., , and Randall D. A. , 1996: Explicit simulation of cumulus ensembles with the GATE Phase III data: Comparison with observations. J. Atmos. Sci., 53 , 37093736.

    • Search Google Scholar
    • Export Citation
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The Sensitivity of West African Convective Line Water Budgets to Land Cover

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  • 1 Department of Earth and Atmospheric Sciences, University at Albany, State University of New York, Albany, New York
  • | 2 Physics Department, Austin College, Sherman, Texas
  • | 3 Laboratory for Atmospheres, NASA Goddard Space Flight Center, Greenbelt, Maryland
  • | 4 Department of Earth System Science, University of California, Irvine, Irvine, California
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Abstract

This study used a two-dimensional coupled land–atmosphere (cloud resolving) model to investigate the influence of land cover on the water budgets of convective lines in West Africa. Study simulations used the same initial sounding and one of three different land covers: a sparsely vegetated semidesert, a grassy savanna, and a dense evergreen broadleaf forest. All simulations began at midnight and ran for 24 h to capture a full diurnal cycle. During the morning, the forest had the highest latent heat flux, the shallowest, moistest, slowest growing boundary layer, and more convective available potential energy than the savanna and semidesert. Although the savanna and forest environments produced virtually the same total rainfall mass (semidesert 18%), the spatial and temporal patterns of the rainfall were significantly different and can be attributed to the boundary layer evolution. The forest produced numerous convective cells with very high rain rates mainly during the early afternoon. During the morning, the savanna built up less but still significant amounts of convective available potential energy and enough convective inhibition so that the strongest convection in the savanna did not occur until late afternoon. This timing resulted in the largest, most intense convective line of the three land covers.

Corresponding author address: Karen I. Mohr, Department of Earth and Atmospheric Sciences, University at Albany, SUNY, Albany, NY 12222. Email: mohr@atmos.albany.edu

Abstract

This study used a two-dimensional coupled land–atmosphere (cloud resolving) model to investigate the influence of land cover on the water budgets of convective lines in West Africa. Study simulations used the same initial sounding and one of three different land covers: a sparsely vegetated semidesert, a grassy savanna, and a dense evergreen broadleaf forest. All simulations began at midnight and ran for 24 h to capture a full diurnal cycle. During the morning, the forest had the highest latent heat flux, the shallowest, moistest, slowest growing boundary layer, and more convective available potential energy than the savanna and semidesert. Although the savanna and forest environments produced virtually the same total rainfall mass (semidesert 18%), the spatial and temporal patterns of the rainfall were significantly different and can be attributed to the boundary layer evolution. The forest produced numerous convective cells with very high rain rates mainly during the early afternoon. During the morning, the savanna built up less but still significant amounts of convective available potential energy and enough convective inhibition so that the strongest convection in the savanna did not occur until late afternoon. This timing resulted in the largest, most intense convective line of the three land covers.

Corresponding author address: Karen I. Mohr, Department of Earth and Atmospheric Sciences, University at Albany, SUNY, Albany, NY 12222. Email: mohr@atmos.albany.edu

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