Shelterbelts are receiving renewed interest in the US as a means of promoting sustainable agriculture and ecological diversity in intensely cropped agricultural landscapes. Widespread adoption of shelterbelts in intensely cropped areas will require careful design to maintain high agricultural yields while concurrently achieving a more diverse and sustainable agricultural ecosystem.
Understanding how the shelter modifies the wind-flow field is the first step in evaluating the complete microclimatic impact of the shelter and therefore its effect on agricultural yields of sheltered crops. Changes in humidity, carbon dioxide, evaporation, heat loss, and snow deposition also are created in the sheltered crop. Under this project, measurements will be taken of mean and turbulent flow fields and associated microclimatic variables in the vicinity of shelterbelts. These measurements, together with measurements of the resistance of the shelterbelt to penetration by the wind (porosity) will be used to develop a mathematical model for describing the microclimate changes produced by the shelterbelt. This model will be used by a shelterbelt specialist to design the optimum configuration of the shelterbelt (i.e., type of trees, distance between trees, number of rows of trees, distance between rows) to achieve a particular modification of the microclimate in the sheltered crop.
Procedures similar to those being developed in this project have been used in Russia for several years. The developer of the Russian shelterbelt model is a member of our multi-institutional research team and will participate in the measurement and modeling effort.
Litvina, I. V., and E. S. Takle, 1993: Design of porous-plant windbreaks for management of surface-layer parameters. In Soil and Plants - Processes and Modeling, I. Uskov (editor), 87-94. (Published in Russian)
Wang, H., and E. S. Takle, 1994: Boundary-layer flow and turbulence near porous obstacles. I. Derivation of a general equation set for a porous medium. Boundary-Layer Meteorology (in press).
Wang, H., and E. S. Takle, 1994: Simulations of shelterbelt effects on wind direction. Accepted by Jl. Appl. Meteorol..
Wang, H., and E. S. Takle, 1994: Numerical simulation of boundary-layer flows near shelterbelts. Accepted by Boundary Layer Meteor.
Wang, H., and E. S. Takle, 1994: On shelter efficiency of shelterbelts in oblique winds. To be submitted to Agric. and Forest Meteorology.
Wang, H., and E. S. Takle, 1994: On three-dimensionality of shelterbelt structure and its influences on shelter effects. To be submitted to Boundary-Layer Meteorology. 70pp.
Litvina, I. V., and E. S. Takle, 1993: Designing shelterbelts by use of a turbulence model. Proceedings, 4th International Symposium on Windbreaks and Agroforestry, 24-27. Viborg, Denmark.
Litvina, I. V., and E. S. Takle, 1993: Snow deposition by shelterbelts as a means of reducing fire potential. 12th International Conf. on Fire and Forest Meteorology. Jekyll Is. Ga.
Wang,H., and E. S. Takle, 1994: Interaction of Synoptic Flow and Mesoscale Circulation as a Function of Synoptic Windspeed. Preprints, Sixth Conference on Mesoscale Processes, Portland, Amer. Meteor. Soc., J36-J39.
Wang, H., and E. S. Takle, 1994: Mesoscale and Boundary-Layer Flows over Inhomogeneous Surfaces Consisting of Porous Obstacles. Preprints, Sixth Conference on Mesoscale Processes, Portland, Amer. Meteor. Soc., 262-265.
Wang, H., and E. S. Takle, 1995: Equations for mean and turbulent flow through and over porous obstacles. Eleventh Symposium on Boundary Layers and Turbulence, Charlotte. Amer. Meteor. Soc.
Wang, H., and E. S. Takle, 1995: Simulations of mean and turbulent properties of oblique flows near agricultural shelterbelts. Eleventh Symposium on Boundary Layers and Turbulence, Charlotte. Amer. Meteor. Soc.
Schmidt, R. A., E. S. Takle, J. R. Brandle, and I. V. Litvina, 1995: Static pressure at the ground under atmospheric flow across a windbreak. Eleventh Symposium on Boundary Layers and Turbulence, Charlotte. Amer. Meteor. Soc.
Schmidt, R. A., R. L. Jairell, J. R. Brandle, E. S. Takle, and I. V. Litvina, 1995: Windbreak shelter as a function of wind direction. Ninth Symposium on Meteorological Observations and Instrumentation, Charlotte. Amer. Meteor. Soc.
Litvina, I. V.,E. S. Takle, J. Prueger, R. A. Schmidt, and J. R. Brandle, 1995: Atmospheric density fluctuations in the surface layer near shelterbelts. Ninth Symposium on Meteorological Observations and Instrumentation, Charlotte. Amer. Meteor. Soc.
Prueger, J., T. Sauer, E. S. Takle, I. V. Litvina, R. A. Schmidt, J.R. Brandle, and J. L. Hatfield, 1995: Windbreak shelter effects on surface energy balance components. Ninth Symposium on Meteorological Observations and Instrumentation, Charlotte. Amer. Meteor. Soc.
Alkhalil, A., I. V. Litvina, R. A. Schmidt, J. R. Brandle, and E. S. Takle, 1995: Determination of shelterbelt porosity parameters from measurements and a model. Ninth Symposium on Meteorological Observations and Instrumentation, Charlotte. Amer. Meteor. Soc.
Zhou, X., J. R. Brandle, E. S. Takle, R. A. Schmidt, R. L. Jairell, E. Daningsih, and L. Hodges, 1995: A new method to estimate the aerodynamic density of field shelterbelts. Annual Meeting of the American Agronomy Society, October 29-November 3. St. Louis.
Brandle, J. R., R. A. Schmidt, E. S. Takle, I. V. Litvina, X. Ahou, D. S. Zhang, R. L. Jairell, and W. E. Easterling, 1995: Comparison of wind profiles and microclimate in a series of parallel shelterbelts. Annual Meeting of the American Agronomy Society, October 29-November 3. St. Louis.