Sensitivity analysis of a land surface scheme using multicriteria methods

Attempts to model surface-atmosphere interactions with greater physical rea lism have resulted in complex land surface schemes (LSS) with large numbers of parameters. A companion paper describes a multicriteria calibration pro cedure for extracting plot-scale estimates of the preferred ranges of these parameters from the various observational data sets that are now available . A complementary procedure is presented in this paper that provides an obj ective determination of the multicriteria sensitivity of the modeled variab les to the parameters, thereby allowing the number of calibration parameter s and hence the computational effort to be reduced. Two case studies are re ported for the BATS model using data sets of typical quality but very diffe rent location and climatological regime (ARM-CART and Tucson). The sensitiv ity results were found to be consistent with the physical properties of the different environments, thereby supporting the reasonableness of the model formulation. Further, when the insensitive parameters are omitted from the calibration process, there is little degradation in the quality of the mod el description and little change in the preferred range of the remaining pa rameters.