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Journal of Applied Meteorology and Climatology

  • Barfield, B. J., K. B. Perry, J. D. Martsolf, and C. T. Morrow, 1990: Modifying the aerial environment. Management of Farm Irrigation Systems, ASAE Monogr., No. 22, Amer. Soc. Agric. Eng., 825–869.

  • Batchelor, G. K., 1970: An Introduction to Fluid Dynamics. Cambridge University Press, 615 pp.

  • Businger, J. A., 1965: Frost protection with irrigation. Agricultural Meteorology, Meteor. Monogr., No. 28, Amer. Meteor. Soc., 74–80.

  • Chen, E., L. H. Allen Jr., J. F. Bartholic, and J. F. Gerber, 1983: Comparison of winter-nocturnal geostationary satellite infrared-surface temperature with shelter-height temperature in Florida. Remote Sens. Environ.,13, 313–327.

  • Gerber, J. F., and D. S. Harrison, 1964: Sprinkler irrigation for cold protection of citrus. Trans. ASAE,7, 464–467.

  • Gilabert, M. A., D. Segarra, and J. Meliá, 1994: Simulation of citrus orchard reflectance by means of a geometrical canopy model. Int. J. Remote Sens.,15, 2559–2582.

  • Kalma, J. D., and M. Fuchs, 1975: Citrus orchards. Case Studies, Vol. 2, J. L. Monteith, Ed., Vegetation and the Atmosphere, Academic Press, 309–328.

  • ——, G. P. Laughlin, J. M. Caprio, and P. J. C. Hamer, 1992: The Bioclimatology of Frost. Springer-Verlag, 144 pp.

  • Ludlam, F. H., 1980: Clouds and Storms. The Pennsylvania State University Press, 405 pp.

  • Martsolf, J. D., 1990: Cold protection strategies. Proc. Fl. State. Hortic. Soc.,103, 72–78.

  • ——, 1992a: Energy requirements for frost protection of horticultural crops. Energy in Farm Production, R. C. Fluck, Ed., Elsevier, 219–239.

  • ——, 1992b: Cold protection mechanisms. Proc. Fl. State. Hortic. Soc.,105, 91–94.

  • ——, 1993: Evaporation and wind: Friend orfoe in cold protection. Proc. Fl. State. Hortic. Soc.,106, 65–70.

  • Oswalt, T. W., and L. R. Parsons, 1981: Observations on micro sprinkler use for cold protection during the 1981 freeze. Proc. Fl. State. Hortic. Soc.,94, 52–54.

  • Perry, K. B., J. D. Martsolf, and C. T. Morrow, 1980: Conserving water in sprinkling for frost protection by intermittent application. J. Amer. Soc. Hortic. Sci.,105, 657–660.

  • Smith, E. A., W. L. Crosson, and B. D. Tanner, 1992: Estimation of surface heat and moisture fluxes over a prairie grassland. Part I: In situ measurements incorporating a cooled mirror dew point hygrometer. J. Geophys. Res.,97, 18 583–18 598.

  • Sutherland, R. A., H. E. Hannah, A. F. Cook, and J. D. Martsolf, 1981: Remote sensing of thermal radiation from an aircraft: An analysis and evaluation of crop freeze methods. J. Appl. Meteor.,20, 813–820.

  • Wallis, R., 1963: Effectiveness of freeze protection during the freeze of December, 1962. Citrus Ind.,44, 21–22.

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Editorial Type:
Article
Article Type:
Research Article

Spray Irrigation Effects on Surface-Layer Stability in an Experimental Citrus Orchard during Winter Freezes

Harry J. CooperDepartment of Meteorology and Supercomputer Computations Research Institute, The Florida State University, Tallahassee, Florida

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Eric A. SmithDepartment of Meteorology and Supercomputer Computations Research Institute, The Florida State University, Tallahassee, Florida

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J. David MartsolfHorticultural Sciences Department and Institute for Food and Agricultural Sciences, University of Florida, Gainesville, Florida

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Print Publication:
01 Feb 1997
DOI:
https://doi.org/10.1175/1520-0450(1997)036<0155:SIEOSL>2.0.CO;2
Page(s):
155–166
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Abstract

Observations taken by two surface radiation and energy budget stations deployed in the University of Florida/Institute for Food and Agricultural Service experimental citrus orchard in Gainesville, Florida, have been analyzed to identify the effects of sprayer irrigation on thermal stability and circulation processes within the orchard during three 1992 winter freeze episodes. Lapse rates of temperature observed from a micrometeorological tower near the center of the orchard were also recorded during periods of irrigation for incorporation into the analysis. Comparisons of the near-surface temperature lapse rates observed with the two energy budget stations show consistency between the two sites and with the tower-based lapse rates taken over a vertical layer from 1.5 to 15 m above ground level. A theoretical framework was developed that demonstrates that turbulent-scale processes originating within the canopy, driven by latent heat release associated with condensation and freezing processes from water vapor and liquid water released from sprayer nozzles, can destabilize lapse rates and promote warm air mixing above the orchard canopy. The orchard data were then analyzed in the context of the theory for evidence of local overturning and displacement of surface-layer air, with warmer air from aloft driven by locally buoyant plumes generated by water vapor injected into the orchard during the irrigation periods. It was found that surface-layer lapse rates were lower during irrigation periods than under similar conditions when irrigation was not occurring, indicating a greater degree of vertical mixing of surface-layer air with air from above treetops, as a result of local convective overturning induced by the condensation heating of water vapor released at the nozzles of the sprinklers. This provides an additional explanation to the well-accepted heat of fusion release effect, of how undertree irrigation of a citrus orchard during a freeze period helps protect crops against frost damage.

Corresponding author address: Harry J. Cooper, Dept. of Meteorology, The Florida State University, Tallahassee, FL 32306.

esmith@metsat.met.fsu.edu

Abstract

Observations taken by two surface radiation and energy budget stations deployed in the University of Florida/Institute for Food and Agricultural Service experimental citrus orchard in Gainesville, Florida, have been analyzed to identify the effects of sprayer irrigation on thermal stability and circulation processes within the orchard during three 1992 winter freeze episodes. Lapse rates of temperature observed from a micrometeorological tower near the center of the orchard were also recorded during periods of irrigation for incorporation into the analysis. Comparisons of the near-surface temperature lapse rates observed with the two energy budget stations show consistency between the two sites and with the tower-based lapse rates taken over a vertical layer from 1.5 to 15 m above ground level. A theoretical framework was developed that demonstrates that turbulent-scale processes originating within the canopy, driven by latent heat release associated with condensation and freezing processes from water vapor and liquid water released from sprayer nozzles, can destabilize lapse rates and promote warm air mixing above the orchard canopy. The orchard data were then analyzed in the context of the theory for evidence of local overturning and displacement of surface-layer air, with warmer air from aloft driven by locally buoyant plumes generated by water vapor injected into the orchard during the irrigation periods. It was found that surface-layer lapse rates were lower during irrigation periods than under similar conditions when irrigation was not occurring, indicating a greater degree of vertical mixing of surface-layer air with air from above treetops, as a result of local convective overturning induced by the condensation heating of water vapor released at the nozzles of the sprinklers. This provides an additional explanation to the well-accepted heat of fusion release effect, of how undertree irrigation of a citrus orchard during a freeze period helps protect crops against frost damage.

Corresponding author address: Harry J. Cooper, Dept. of Meteorology, The Florida State University, Tallahassee, FL 32306.

esmith@metsat.met.fsu.edu

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