A model to evaluate windbreak protection efficiency |
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| Authors: | H Zhang J R Brandle G E Meyer L Hodges |
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| Institution: | (1) Department of Forestry, Fisheries and Wildlife, University of Nebraska-Lincoln, 68583-0814 Lincoln, NE, USA;(2) Present address: UCLA-DOE Laboratory, University of California, 90024-1786 Los Angeles, CA, USA;(3) Department of Biological Systems Engineering, University of Nebraska-Lincoln, 68583-0726 Lincoln, NE, USA;(4) Department of Horticulture, University of Nebraska-Lincoln, 68583-0724 Lincoln, NE, USA |
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| Abstract: | The effectiveness of windbreaks in windspeed reduction is often evaluated without regard to the objects to be protected. In fact, many objects may have different sensitivities to wind and often require different degrees of wind protection. Since commonly used indexes do not consider the sensitivity to wind, a concept of specific protection efficiency is developed. A critical windspeed is used to represent the sensitivity of each object. Windspeeds greater than this value are considered damaging. A dimensionless protection index is defined to evaluate windbreak efficiency. The maximum index value is 1 for the highest protection, and the index is negative when sheltered windspeed is greater than the critical windspeed. This index can be compared, summed, and averaged across different windbreaks, objects, and leeward locations. A sample of critical windspeed values was compiled from the literature. The index was evaluated using actual wind data measured under both sheltered and open conditions. The results indicated that the index can be used for evaluating windbreak effectiveness in terms of objects protected under various conditions. This model could be used as a tool for windbreak-related research and policy making. |
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| Keywords: | windbreaks shelterbelt wind model specific protection efficiency |
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