bReeze (version 0.1-0)

monthStats: Calculation of monthly means

Description

Calculates monthly means of wind speed.

Usage

monthStats(mast, set)

Arguments

mast

Met mast object created by createMast.

set

Set used for calculation as integer value. If missing, the calculation is carried out for all datasets that contain average wind speed v.avg.

Value

• Returns a list of data frames (one for each dataset) containing monthly, annual and total means of wind speed.

encoding

UTF-8

Details

monthStats averages valid wind speed data for each month and year in the measurement period. Means strongly depend on the measurement period and the number of samples. One important requirement for a reliable wind assessment is a measurement period covering the full seasonal cycle of variations. A typical bias is a measurement limited to winter months, which usually results in overestimated wind speeds.

References

Brower, M., Marcus, M., Taylor, M., Bernadett, D., Filippelli, M., Beaucage, P., Hale, E., Elsholz, K., Doane, J., Eberhard, M., Tensen, J., Ryan, D. (2010) Wind Resource Assessment Handbook. http://www.awstruepower.com/wp-content/uploads/2012/01/10-30_wind-resource-handbook.pdf

See Also

createMast, plotMonthStats

Examples

# load and prepare data
data(winddata)
set40 <- createSet(height=40, v.avg=winddata[,2])
set30 <- createSet(height=30, v.avg=winddata[,6])
set20 <- createSet(height=20, v.avg=winddata[,10])
ts <- formatTS(winddata[,1])
neubuerg <- createMast(time.stamp=ts, loc=NULL, desc=NULL, 
	set40, set30, set20)
neubuerg <- clean(neubuerg)

# calculate monthly means
neubuerg.stats <- monthStats(neubuerg)

# calculate monthly means for one dataset
neubuerg.stats.2 <- monthStats(mast=neubuerg, set=1)

# compare output
neubuerg.stats
neubuerg.stats.2