3.1. Validation results
Comparisons between wind speeds derived from the model and that obtained from the measurements were examined for various averaging periods at the hourly, 3-hourly, monthly and yearly scales. The comparisons are summarized in Table 1. It can be seen that the discrepancies decrease with increasing time averaging periods. High errors are observed in hourly averages, especially at Chiang Mai and Khonkaen. Lower differences between estimated wind speed and measurements are found at Bangkok and Songkhla stations. From Table 1, it is also noticed that the distances between the wind measurement masts and the radiosonde stations have no systematic effect on the differences.