Fig. 1. Contours of the objective function in the three parameter planes (a) log(k_abs)–log(p_e), (b) log(k_abs)–, and (c) –log(p_e) (from Finsterle and Faybishenko, 1999). The first row shows the objective function when only cumulative outflow data are used, the second row includes only pressure data, and the third row comprises both the cumulative outflow and pressure data. The planes intersect the parameter space at the global minimum; that is, they contain the best estimate parameter set.