VALIDATION AND SENSITIVITY TESTS ON IMPROVED PARAMETRIZATIONS OF A LAND-SURFACE PROCESS MODEL (LSPM) IN THE PO VALLEY

The Land Surface Process Model (LSPM) has been improved with respect t o the Ist version of 1994. The modifications have involved the paramet rizations of the radiation terms and of turbulent heat fluxes. A param etrization of runoff has also been developed, in order to close the hy drologic balance. This 2nd version of LSPM has been validated against experimental data gathered at Mottarone (Verbania, Northern Italy) dur ing a field experiment. The results of this validation show that this new version is able to apportionate the energy into sensible and laten t heat fluxes. LSPM has also been submitted to a series of sensitivity tests in order to investigate the hydrological part of the model. The physical quantities selected in these sensitivity experiments have be en the initial soil moisture content and the rainfall intensity. In ea ch experiment, the model has been forced by using the observations car ried out at the synoptic stations of San Pietro Capofiume (Po Valley, Italy). The observed characteristics of soil and vegetation (not invol ved in the sensitivity tests) have been used as initial and boundary c onditions. The results of the simulation show that LSPM can reproduce well the energy, heat and water budgets and their behaviours with vary ing the selected parameters. A careful analysis of the LSPM output sho ws also the importance to identify the effective soil type.