Hybrid model

Using Kang's (2000) Hybrid Model, it was possible to obtain the average soil temperature in the Pelotas-RS region, mainly from average air temperature information. This model is based on an empirical relationship between air and soil temperature, as well as on the physics of heat transfer. The results generated by the model were compared with data collected at the UFPel Agroclimatological Station, located in Capão do Leão-RS, between 1966 and 1988. The results of the estimated average soil temperature at depths of 5, 10, and 20 cm were analyzed. For a depth of 5 cm, the model generated the best results for average daily temperatures in relation to the observed data. The season best represented was winter, with summer being the most discrepant. The standard deviation of the data for the entire observation period was identical to the value of the simulated data. In addition, the model reproduced the same pattern of variability and average values of the observed data, although there was an underestimation of temperature values for depths of 10 and 20 cm, despite the lower dispersion observed in relation to the measured values.