A Probabilistic Method Predicting Forest Fire Occurrence Combining Firebrands and the Weather-Fuel Complex in the Northern Part of the Daxinganling Region, China

Ping Sun,Yunlin Zhang

doi:10.3390/f9070428

Abstract

The fire danger rating method currently used in the northern part of the Daxinganling Region with the most severe forest fires in China only uses weather variables without considering firebrands. The discrepancy between fire occurrence and fire risk by FFDWR (Forest Fire-Danger Weather Rating, a method issued by the National Meteorological Bureau, that is used to predict forest fire probability through links between forest fire occurrence and weather variables) in the northern part is more obvious than that in the southern part. Great discrepancy has emerged between fire danger predicted by the method and actual fire occurrence in recent years since a strict firebrand prohibition policy has significantly reduced firebrands in the region. A probabilistic method predicting fire probability by introducing an Ignition Component (IC) in the National Fire Danger Rating System (NFDRS) adopted in the United States to depict effects of both firebrand and weather-fuel complex on fire occurrence is developed to solve the problem. The suitability and accuracy of the new method in the region were assessed. Results show that the method is suitable in the region. IC or the modified IC can be adopted to depict the effect of the weather-fuel complex on fire occurrence and to rate fire danger for periods with fewer firebrands. Fire risk classes and corresponding preparedness level can be determined from IC in the region. Methods of the same principle could be established to diminish similar discrepancy between actual fire occurrence and fire danger in other countries.

Highlights

Fire danger rating is the first step in forest fire prevention
A linear fitting of the higher than the second power form from the relationship is a major source of error in daily fire probability prediction, which resulted in under-estimation of daily fire probability at higher Ignition Component (IC) and over-estimation of daily fire probability at lower IC
Other modifications to the calculation of ignition probability and probability of an ignition spreading to a reportable fire, which maintains the linear relationship between fire probability and IC, are valid

Summary

Introduction

Fire danger rating is the first step in forest fire prevention. A fire danger rating system suited to a region would generate valuable fire risk information for forest fire prevention and suppression.The current fire danger rating assessment method adopted in China is a method developed by the National Meteorological Bureau in 2007, named Forest Fire-Danger Weather Rating (FFDWR).The method predicts forest fire probability through links between forest fire occurrence and weather variables obtained by pure statistical analysis of historical fire data and weather variables. One problem in using the method to calculate fire danger in the region is that fewer fires occur per days with higher fire danger indices, similar to that in Southern Europe [1] because tighter firebrand (the pieces of material dropped by humans) restriction measures are usually taken on these days, which results in fewer firebrands. This is contradictory to the common sense that the higher the fire danger, the more fires. The discrepancy is getting larger and more obvious in recent years since tighter fire prevention measures have been taken in the region, which strongly reduces firebrands, leading to markedly

Methods

Results

Conclusion