Original Paper

Theoretical and Applied Climatology

, Volume 102, Issue 3, pp 429-438

First online:

An integrated evaluation of thirteen modelling solutions for the generation of hourly values of air relative humidity

  • Simone BregaglioAffiliated withDepartment of Crop Science, University of MilanAgriculture Research Council, Research Centre for Industrial Crops Email author 
  • , Marcello DonatelliAffiliated withEuropean Commission Directorate General Joint Research Centre, Institute for Security and Protection of the CitizenAgriculture Research Council, Research Centre for Industrial Crops
  • , Roberto ConfalonieriAffiliated withDepartment of Crop Science, University of Milan
  • , Marco AcutisAffiliated withDepartment of Crop Science, University of Milan
  • , Simone OrlandiniAffiliated withDepartment of Agronomy and Land Management, University of Florence

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The availability of hourly air relative humidity (HARH) data is a key requirement for the estimation of epidemic dynamics of plant fungal pathogens, in particular for the simulation of both the germination of the spores and the infection process. Most of the existing epidemic forecasting models require these data as input directly or indirectly, in the latter case for the estimation of leaf wetness duration. In many cases, HARH must be generated because it is not available in historical series and when there is the need to simulate epidemics either on a wide scale or with different climate scenarios. Thirteen modelling solutions (MS) for the generation of this variable were evaluated, with different input requirements and alternative approaches, on a large dataset including several sites and years. A composite indicator was developed using fuzzy logic to compare and to evaluate the performances of the models. The indicator consists of four modules: Accuracy, Correlation, Pattern and Robustness. Results showed that when available, daily maximum and minimum air relative humidity data substantially improved the estimation of HARH. When such data are not available, the choice of the MS is crucial, given the difference in predicting skills obtained during the analysis, which allowed a clear detection of the best performing MS. This study represents the first step of the creation of a robust modelling chain coupling the MS for the generation of HARH and disease forecasting models, including the systematic validation of each step of the simulation.