Estimation of Winds Over the Great Lakes.
ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MISS
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Past efforts to estimate wind speeds over a large lake have met with very limited success. The purpose of this study is to demonstrate that, with a combined theoretical-empirical approach, winds over a lake can be obtained from transformed wind speeds at nearby land stations. The theoretical results provide a basis for comparison of many empirical data sets and establish a rational means of analyzing the expected differences between winds over land and those over a marine surface. This in turn affords a means of examining systematic variations in the ratio of wind speeds over a lake to wind speeds over land. The good agreement between theory and observation indicates that wind estimates over the lake can be made for a wide range of synoptic conditions with an rms error of under 5 knots. The theoretical curve for the lake windland wind ratio provides a stable estimate of lake winds well beyond wind speeds for which there is good empirical data. Consequently, the technique presented here offers relatively good accuracy even in extreme wind conditions where there are little or no direct measurements of winds over the lake.