|
*Extrema |
 
|
*Extrema
|
*Extrema |
|
To specify the procedure and input parameters to be used in the computation of extreme values.
Refer to Extreme Values for further information on this feature.
A block of two lines of data. The first line defines the procedure to be used in the computation of extreme values. The second line defines the necessary input parameters.
Line defining the extreme value calculation procedure:
TYPE=Calculation Procedure
The next line defines the parameters required for extreme value postprocessing. The format depends on the Calculation Procedure specified – the options are RAYLEIGH (the default) and WEIBULL. For RAYLEIGH extrema postprocessing, the line takes the following format:
DATA=[Storm Duration] [, Probability] [, Calculation Start Time]
For WEIBULL extrema postprocessing, it takes the following format:
DATA=[Storm Duration] [, Probability] [, Threshold] [, Calculation Start Time]
Calculation Procedure can be RAYLEIGH or WEIBULL. Storm Duration defaults to 3 hours and Probability to 0.01 (1%). Threshold defaults to 1. Calculation Start Time defaults to the analysis start time.
Input: |
Description |
Storm Duration: |
The storm duration in hours to be used when calculating extreme values. The default is 3 hours. |
Probability: |
The exceedance probability to be used when calculating extreme values. The default is 0.01 (= 1%). |
Start Time: |
The time in the analysis to start the extreme value calculation. Use this entry to exclude initial transients from the calculation. The default is the database output start time. See Note (b). |
Input: |
Description |
Storm Duration: |
The storm duration in hours to be used when calculating extreme values. The default is 3 hours. |
Probability: |
The exceedance probability to be used when calculating extreme values. The default is 0.01 (= 1%). |
Threshold: |
The proportion of largest maximums /smallest minimums to be used when calculating extreme values. The default is 1. See Note (c). |
Start Time: |
The time in the analysis to start the extreme value calculation. Use this entry to exclude initial transients from the calculation. The default is the database output start time. See Note (b). |
(a)Refer to Extreme Values for a detailed discussion of all aspects of specifying data relating to extreme value postprocessing.
(b)The duration of the timetrace (end time minus start time) can be less than the storm duration.
(c)A threshold equal to 1 denotes all the maximums/minimums in the timetrace will be used to calculate the extreme values. A threshold equal to 1/n (e.g. 1/3) uses the upper 1/n of largest maximums and lowest 1/n of smallest minimums to calculate the extreme value.
(d)Note that the Extreme Values – Rayleigh and Extreme Values – Weibull tables are mutually exclusive. Specification of data in either table indicates the extreme value postprocessing approach which you wish to use.