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 All Topics | Topic "Random variation in climate variables"

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 Dr. Patrick Keys Subject: Random variation in climate variables   Posted: 7/13/2012 Viewed: 22929 times Hello, I am simulating streamflow in a sub-basin of the Volta basin, and I am trying to simulated random variation in climate, using the Random function in WEAP. I am trying to prescribe Monthly bounds for this random variation. For example, for temperature, each month has a different set of low and high bounds in which to randomly vary. Does anyone know how to use expression builder, or something else, to develop this monthly random variation? Thank you, Patrick
 Mr. Jack Sieber Subject: Re: Random variation in climate variables   Posted: 7/13/2012 Viewed: 22902 times The form of the Random function that you want is Random(LowerBound, UpperBound), where the lower and upper bounds will vary by month. If the lower temperature bound in each month is: MonthlyValues( Jan, 0, Feb, 10, Mar, 20, Apr, 40, May, 50, Jun, 60, Jul, 65, Aug, 65, Sep, 55, Oct, 45, Nov, 35, Dec, 15 ) and the upper temperature bound in each month is: MonthlyValues( Jan, 40, Feb, 50, Mar, 60, Apr, 70, May, 75, Jun, 80, Jul, 85, Aug, 85, Sep, 75, Oct, 70, Nov, 60, Dec, 50 ) Then the expression to pick a random value in each month between the lower and upper bounds is: Random( MonthlyValues( Jan, 0, Feb, 10, Mar, 20, Apr, 40, May, 50, Jun, 60, Jul, 65, Aug, 65, Sep, 55, Oct, 45, Nov, 35, Dec, 15 ), MonthlyValues( Jan, 40, Feb, 50, Mar, 60, Apr, 70, May, 75, Jun, 80, Jul, 85, Aug, 85, Sep, 75, Oct, 70, Nov, 60, Dec, 50 )) Note, however, that the Random function will give a uniform distribution of values between lower and upper bounds. This will mean that the lower and upper extremes will occur with the same frequency as the average. Depending on your choice of bounds (e.g,. historical min and max temperatures), this may give very unreasonable (extreme) values. Jack
Dr. Patrick Keys

Subject: Re: Random variation in climate variables
Posted: 7/13/2012 Viewed: 22893 times
Thanks Jack,