Wind Speed Direction Research Articles

Factors Affecting the Performance of a Photovoltaic Power System (PVPS)

Abstract The paper presents a comprehensive experimental study of the effects of environmental factors on both the efficiency and the electrical power output of a 160-arrays photovoltaic power system. Direct normal (DN) isolation, ambient temperature and wind speed are considered as the key environmental parameters in this study. These environmental factors are location dependent and their effects vary accordingly.

Closure to “ Multivariate Distributions of Directional Wind Speeds ” by Emil Simiu, Erik M. Hendrickson, William A. Nolan, Ingram Olkin, and Clifford H. Spiegelman (April, 1985, Vol. 111, No. 4)

Closure to “ <i>Multivariate Distributions of Directional Wind Speeds</i> ” by Emil Simiu, Erik M. Hendrickson, William A. Nolan, Ingram Olkin, and Clifford H. Spiegelman (April, 1985, Vol. 111, No. 4)

Discussion of “ Multivariate Distributions of Directional Wind Speeds ” by Emil Simiu, Erik M. Hendrickson, William A. Nolan, Ingram Olkin, and Clifford H. Spiegelman (April, 1985, Vol. 111, No. 4)

Discussion of “ <i>Multivariate Distributions of Directional Wind Speeds</i> ” by Emil Simiu, Erik M. Hendrickson, William A. Nolan, Ingram Olkin, and Clifford H. Spiegelman (April, 1985, Vol. 111, No. 4)

Multivariate Distributions of Directional Wind Speeds

The probability of failure of a structure or structural element subjected to wind forces depends, in large part, on the distribution of extreme wind speeds acting on the structure. In the past, distributions of extreme wind speeds were based on extreme wind data without regard to wind direction, and probabilities of failure were computed accordingly. A method is presented herein for calculating failure probabilities by using directional wind speed data as obtained from weather station records. The method takes advantage of the weak correlations found among wind speeds from different directions and the property of extreme value random variables that zero correlation implies statistical independence. The method is applicable to any type of structure, including structures exhibiting aerodynamic amplification or aeroelastic effects. In addition, it is shown that, in practice, the necessary distributions can be estimated almost as accurately from data obtained from readily available published documents as from...

Trends in summer visibility in London and Southern England 1962–1979

Visibility data from five sites in London and southern England are analysed to detect long term trends. At all sites a steady deterioration in summer visibility up to 1973 has occurred, especially in the long-range categories. After 1973 a sharp improvement is evident which has been maintained to the present. It is suggested that the most likely cause of these changes is the occurrence of high concentrations of photochemically produced sulphate aerosols. Visibility improvements after 1973 do not appear to be related to changes in wind direction frequency, wind speeds, or duration of bright sunshine and it is suggested that a decrease in aerosol sulphate formation may have resulted from decreased oil consumption by power stations and industry immediately after the 1973 oil crisis.