Prediction of the daily number of forest fires

Abstract

On the basis of a qualitative index (Daily Fire Risk) for the meteorological severity, a model for predicting the daily number of forest fires over a zone is developed. DFR is obtained for each day from (e, D) values, where e is the parameter of stability in the lowest atmospheric layer (850–700 hPa) and D is the saturation deficit at lowest level (850 hPa). Both e and D are evaluated at 00.00 UTC from radwindsonde data. Four types of day may be described: I, II, III and IV-type if a classification on (e, D) values is established. Very High fire activity is associated with type-I days; High with Type-III; Low with type IV and Very Low with type-II days. As in the case of other qualitative indices, two days which present an identical index may register a very different number of forest fires. This is due to the fact that the fire activity on a day d does not depend exclusively upon meteorological parameters of the day d. A second question to consider is related to the prediction of the daily number of fires PNF(d). In this way, an initial hypothesis may be PNF(d) = PW(d) W(d), in which PW(d) and W(d) are the Past Weather and the (present) Weather for each day d. If several considerations such as PW(d) ≈ PW(d–1) are introduced, a working expression for the daily number of forest fires results. The results obtained confirm the utility of the model and, consequently, it should be used to establish correct antifire management.