MARINE METEOROLOGY: INVESTIGATIONS INTO A METHOD OF SHEARING STRESS DETERMINATIONS FROM AN AIRPLANE IN FLIGHT

A method is described for measuring shearing stresses and eddy viscosities of the atmosphere in regions which are not accessible to ground- based instruments. An airplane is used both as a meteorological instrument and an observation base. The method is based upon determining the average of the cross products of the horizontal and vertical components of the wind fluctuations. The eddy viscosity, wind shear, and shearing stress are obtained by analyzing and accounting for the flight and lift characteristics of the airplane together with the readings from a pressure gage anemometer, a vertical accelerometer, a gyroscope, and a drift sight meter. The probable errors of the shearing-stress determination are discussed, and the computed errors indicate that in rough air with large shearing stresses the probable errors are about 5 of the stresses. For very smooth air, the probable error may be 100. The airplane responded completely only to gusts larger than 50 m and failed to measure reliably horizontal gusts larger than 500 to 1000 m this limited the contributions to the shearing stress to gusts within this size range.