STATISTICAL-ANALYSIS FOR THE SPATIAL VALIDITY OF A MODEL TO FORECAST THE DAILY NUMBER OF FOREST-FIRES

In earlier papers a qualitative and quantitative model was developed f or predicting the number of forest fires occurring per day. This model permits the forecast at 00.00 hours Universal Time Convention (UTC) o f any day (d), the number of forest fires per day for a range of sever al days (d to d+5) over a particular region, Input data are the number of forest fires in the region during two preceding days (d-2 and d-1) and the type of day (real and evaluated from radiosonde for d-2, d-1, d and predicted from meteorological medium-range forecasts, i.e. of E uropean Centre, for d+1, d+2, d+3, d+4 and d+5. As this model requires data obtained by radiosonde, particularly temperatures and geopotenti als at 850 and 700 hPa and dew points (or specific humidity) at 850 hP a, this study investigates the spatial validity of the model in relati on to the distance from the radiosonde station (RS). The highest quali ty forecast is obtained for the region immediately surrounding the RS, and diminishes with increasing distance from it, this being due to th e data obtained from the RS not being representative of the atmospheri c column over the region. Hence, the derivation of the critical distan ce for a particular quality level of measurement. Conversely, fixed qu ality level implies a specific separation between RS and the region fo r the prediction, with a higher predictive quality implying a shorter distance.