CLIMATE CHARACTERIZATION AND MODELLING OF PINEAPPLE GREENHOUSES IN THE AZORES ARCHIPELAGO

In the Azores Archipelago, Portugal, pineapples are cultivated on the Island of São Miguel, existing around 60 ha of glasshouses dedicated to this crop, being a very important sector for the local economy. The main goal of this work is to characterise the Azores pineapple glasshouse climate and to develop a model that allows predicting its internal air temperature. Climate data were recorded in two meteorological stations, one located inside the greenhouse and the other outside. Greenhouse climate data showed a more favourable inside air temperature after middle of March, but reaching frequently very high values during the day in all the months analysed, which is a result of traditional greenhouse management and deficient ventilation. In these greenhouses external conditions such as external air temperature, global radiation and day length greatly influenced the climate inside the greenhouses and as a con¬sequence the duration of the different crop phases and fruit quality. A climate model to simulate inside air temperature was developed based on glasshouse characteristics and external climate conditions such as air temperature, solar radiation, ventilation openings and wind velocity. Since most of the time ventilation apertures were closed it was considered an infiltration rate (varying between 1 and 3 air renovation) per hour, as a function of the wind velocity. Validation of the model was performed after calibration and showed good agreement.