Average Wind Parameters Sample Clauses

Average Wind Parameters. Hourly vector (magnitude and direction) mean wind (one-minute average) is available from the Ketchikan Airport. These data have been analyzed and are the subject of a separate wind climatology report (Reference 2). Monthly joint probabilities of wind speed and direction were developed from the Ketchikan Airport wind data. Monthly joint probabilities for May, June, July, August, and September, corresponding to the cruise season in Alaska, were composited to obtain a joint probability distribution of wind speed and direction for the period May through September. This composite joint probability is for a 25-year period of record extending from 1974 through 1999. The composite joint probability is given in Appendix A to this report. The procedure for generating the parameters of a random wind are to generate a random variable, ξ1, from a uniform distribution between zero and one. This random variable is treated as a cumulative probability in order to interpolate a wind speed, U, from a table of cumulative probability of wind speed obtained from the marginal probability of wind speed which in turn is developed from the joint probability distribution given in Appendix A (Ketchikan Airport Wind Climatology [1974-1999]). Table 4.5 is the resulting cumulative probability distribution for one-minute average wind speed at the Ketchikan Airport during the period May through September. A Type-II fit of this cumulative probability distribution is shown in Figure 4.6. Once a one-minute average wind speed, U, has been determined, then the mean direction may be obtained from a double interpolation in a table of conditional probability of wind direction, U_dir, given a wind speed, U. Table 4.6 is the table of cumulative conditional probability of wind direction given wind speed. To interpolate from this table one needs the wind speed, U, obtained using random variable ξ1 and Table 4.5 as well as a new random variable ξ2, also obtained from a uniform distribution between zero and one. Following this Monte Carlo procedure, a one-minute average wind speed, U (knots), and average wind direction, U_dir (degrees true), can be generated. 0 kts 0.000000 0.083333 0.166667 0.250000 0.333333 0.416667 0.500000 0.583333 0.666667 0.750000 0.833333 0.916667 1.000000 2 kts 0.000000 0.066667 0.088889 0.133333 0.222222 0.444444 0.511111 0.600000 0.666667 0.733333 0.777778 0.844444 1.000000 4 kts 0.000000 0.013808 0.024788 0.040426 0.105473 0.306937 0.499085 0.619032 0.686741 0.736483 0.80103...