Wind-erosion Direction Factors as Influenced by Field Shape and Wind Preponderance1
- E. L. Skidmore2
This investigation expands and improves the procedure for determining median travel distance of wind in traversing a field, information used in solving the wind-erosion equation. Wind-erosion roses were simulated by the equation of an ellipse in polar coordinates. The ratio of semimajor axis to semiminor axis was varied to give preponderance values from 1.0 to 4.0. The axis was rotated to simulate field orientation from 0 to 90° relative to prevailing winderosion direction. Length/width ratio for rectangular fields was varied from 1 to 10. The wind-erosion direction factor, a number that when multiplied by field width gives median travel distance, was calculated for many combinations of variables. When preponderance was 1.0, the wind-erosion direction factor was 1.03, 1.42, 1.48, and 1.48 for rectangular fields with length/width ratios of 1, 2, 4, and 10, respectively; the factor was not influenced by field orientation. As preponderance increased, the wind-erosion direction factor approached unity for small angles of deviation and approached the length/width ratio for large angles of deviation. For circular fields surrounded by a nonerodible surface, the wind-erosion direction factor was 0.91, regardless of wind direction and preponderance.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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