NASA STI Repository (National Aeronautics and Space Administration) · 1976 · 10 citations · 0 references
Open access
EngineeringAerospace EngineeringMeteorologyAerodynamicsNumerical Weather PredictionWind EngineeringComputational Wind EngineeringWind ShearBivariate DistributionsConditional Probability ModelsMultivariate Normal DistributionWindWind Direction StatisticsWind Profile AnalysisWind Shear ProfilesWind Speed Statistics
The techniques are presented to derive several statistical wind models. The techniques are from the properties of the multivariate normal probability function. Assuming that the winds can be considered as bivariate normally distributed, then (1) the wind components and conditional wind components are univariate normally distributed, (2) the wind speed is Rayleigh distributed, (3) the conditional distribution of wind speed given a wind direction is Rayleigh distributed, and (4) the frequency of wind direction can be derived. All of these distributions are derived from the 5-sample parameter of wind for the bivariate normal distribution. By further assuming that the winds at two altitudes are quadravariate normally distributed, then the vector wind shear is bivariate normally distributed and the modulus of the vector wind shear is Rayleigh distributed. The conditional probability of wind component shears given a wind component is normally distributed. Examples of these and other properties of the multivariate normal probability distribution function as applied to Cape Kennedy, Florida, and Vandenberg AFB, California, wind data samples are given. A technique to develop a synthetic vector wind profile model of interest to aerospace vehicle applications is presented.