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WEPS Climate Data (Cligen and Windgen)

WEPS Climate Data (Cligen and Windgen). Climate Data. Climate Generation by Stochastic Process. A stochastic process is one involving a randomly determined sequence of observations each of which is considered as a sample of one element from a probability distribution.

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WEPS Climate Data (Cligen and Windgen)

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  1. WEPS Climate Data(Cligen and Windgen)

  2. Climate Data • Climate Generation by Stochastic Process A stochastic process is one involving a randomly determined sequence of observations each of which is considered as a sample of one element from a probability distribution. By stochastically simulating a process, such as weather, one can recreate a series of weather data that statistically mimic the historic record.

  3. Consider a Normal Distribution where the Y-axis represents the probability of some measurement (height of people or wind speed) on the X-Axis.

  4. If the probabilities are cumulated, the distribution looks like the graph above. To stochastically simulate a measurement, one only needs to randomly select a probability and read the corresponding measurement (i.e., wind speed) from the X-Axis.

  5. If random numbers are repeatedly selected and measurements determined, eventually the original historic wind speed distribution will be recreated. Wind speeds typically follow a Weibull Distribution.

  6. Climate Data • Climate Generation by Stochastic Process • WEPS does not use actual data. • It uses statistically probable weather conditions. • This is more appropriate than using measured data (saves computer space) . • WEPS and WEPP use this type of data generation. • The model runs for 15 years to recreate the historical weather distribution and get a stable erosion estimate. • Two steps are used: Statistics are calculated from historic data, then the data is stochastically generated.

  7. Climate Data • WINDGEN Data • WINDGEN was developed specifically for WEPS. • The data comes from a quality-controlled hourly wind data sets. • There are 1304 stations in the 48 state data set. • Stations with less than 5 years of data were excluded to get a good representation of historical winds.

  8. Wind (Windgen) Station Data • Winds>Threshold - 8.0 m/s or 17.9 miles/hr, Units are in hours for the month. • Energy - kJ/m2/Month, stations over 1000 have fair risk of erosion. • Monthly Percent - Percent of the yearly wind energy. • Preponderance - Same as for WEQ • PWED - Prevailing Wind Erosion Direction (16 points of the compass).

  9. Climate Data • Climate Generation by Stochastic Process • Like Windgen, Cligen is a stochastic weather generator which produces daily estimates of precipitation, temperature, dewpoint, wind, and solar radiation for a single geographic point, using monthly parameters (means, SD's, skewness, etc.) derived from the historic measurements.

  10. Climate Data • Temp, Rainfall, Radiation, Dew point are used. • Wind, speed and direction are not used) • CLIGEN

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