Volumetric Efficiency
Volumetric efficiency between sim and obs, with treatment of missing values.
VE(sim, obs, ...) ## Default S3 method: VE(sim, obs, na.rm=TRUE, ...) ## S3 method for class 'data.frame' VE(sim, obs, na.rm=TRUE, ...) ## S3 method for class 'matrix' VE(sim, obs, na.rm=TRUE, ...) ## S3 method for class 'zoo' VE(sim, obs, na.rm=TRUE, ...)
sim |
numeric, zoo, matrix or data.frame with simulated values |
obs |
numeric, zoo, matrix or data.frame with observed values |
na.rm |
a logical value indicating whether 'NA' should be stripped before the computation proceeds. |
... |
further arguments passed to or from other methods. |
VE = 1 - ( sum( abs(obs - sim) ) / sum( obs ) )
Volumetric efficiency was proposed in order to circumvent some problems associated to the Nash-Sutcliffe efficiency. It ranges from 0 to 1 and represents the fraction of water delivered at the proper time; its compliment represents the fractional volumetric mistmach (Criss and Winston, 2008).
Volumetric efficiency between sim and obs.
If sim and obs are matrixes, the returned value is a vector, with the Volumetric efficiency between each column of sim and obs.
obs and sim have to have the same length/dimension
The missing values in obs and sim are removed before the computation proceeds, and only those positions with non-missing values in obs and sim are considered in the computation
Mauricio Zambrano Bigiarini <mzb.devel@gmail.com>
Criss, R. E. and Winston, W. E. (2008), Do Nash values have value? Discussion and alternate proposals. Hydrological Processes, 22: 2723-2725. doi: 10.1002/hyp.7072
obs <- 1:10 sim <- 1:10 VE(sim, obs) obs <- 1:10 sim <- 2:11 VE(sim, obs) ################## # Loading daily streamflows of the Ega River (Spain), from 1961 to 1970 require(zoo) data(EgaEnEstellaQts) obs <- EgaEnEstellaQts # Generating a simulated daily time series, initially equal to the observed series sim <- obs # Computing the volumetric efficiency for the "best" case VE(sim=sim, obs=obs) # Randomly changing the first 2000 elements of 'sim', by using a normal distribution # with mean 10 and standard deviation equal to 1 (default of 'rnorm'). sim[1:2000] <- obs[1:2000] + rnorm(2000, mean=10) # Computing the new volumetric efficiency VE(sim=sim, obs=obs)
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