New Approach to Determine the Sum of the Active Temperatures (SAT) Exemplified by Weather Conditions of Western Malopolska

The paper presents results of research on thermal conditions around the town of Chrzanow in Western Malopolska (southern Poland). The conditions have been determined with the help of the parameter called “sum of active temperatures” (SAT), quite commonly used in climatology and particularly popular among wine growers. New approach in SAT concept has been performed: it’s value has been calculated based on the results of temperature measurements in selected points of environment in which grapevine (Vitis – species) vegetation takes place, that is in the air and in the soil. Moreover, various definitions of “mean temperature” have been applied. The use of different calculation formulae lead to different SAT values. In some cases, the differences in the obtained SAT values reached several percent. This demonstrates the sensitivity of this “measure” in the context of applied computational techniques. Such a conclusion leads to the discussion on the usefulness of calculation formulae used in research on regional climatic conditions, especially in comparative analysis.