Distributed hydrologic modeling of a sparsely monitored basin in Sardinia, Italy, through hydrometeorological downscaling

摘要

The water resources and hydrologic extremes in Mediterranean basins areheavily influenced by climate variability. Modeling these watersheds isdifficult due to the complex nature of the hydrologic response as well asthe sparseness of hydrometeorological observations. In this work, we presenta strategy to calibrate a distributed hydrologic model, known as TIN-basedReal-time Integrated Basin Simulator (tRIBS), in the Rio Mannu basin (RMB),a medium-sized watershed (472.5 km2) located in an agricultural area inSardinia, Italy. In the RMB, precipitation, streamflow and meteorologicaldata were collected within different historical periods and at diversetemporal resolutions. We designed two statistical tools for downscalingprecipitation and potential evapotranspiration data to create the hourly,high-resolution forcing for the hydrologic model from daily records. Despitethe presence of several sources of uncertainty in the observations and modelparameterization, the use of the disaggregated forcing led to goodcalibration and validation performances for the tRIBS model, when dailydischarge observations were available. The methodology proposed here can bealso used to disaggregate outputs of climate models and conducthigh-resolution hydrologic simulations with the goal of quantifying theimpacts of climate change on water resources and the frequency of hydrologicextremes within medium-sized basins.