“…Moreover, the ensemble may not bracket the measurements because all models have similar weaknesses (e.g., no mechanisms for generating infiltration-excess runoff, no vegetation submodel, no representation of the spatial variability in precipitation). Future work is also necessary to both separate errors in model inputs from errors in model structure [e.g., Clark and Slater, 2006;Kavetski et al, 2006aKavetski et al, , 2006b; J. A. Vrugt et al, Treatment of input uncertainty in hydrologic modeling: Doing hydrology backward with Markov Chain Monte Carlo simulation, submitted to Water Resources Research, 2007], and rigorously quantify the independence between different models [e.g., Abramowitz and Gupta, 2008].…”