FARSITE is a spatially and temporally explicit fire simulator system based on the physical statistical fire spread model of Rothermel. This simulator allows the user to describe the spread and behaviour of fire under different terrain, fuels and weather conditions. Although FARSITE was originally developed for long range simulation of prescribed fires in US National Parks and wilderness areas, currently the most common applications of the simulator involve the planning and operational phases of fire management. The use of FARSITE on areas different from those where the simulator was originally developed requires a local calibration to obtain reliable results. The local calibration and validation is particularly important to choose the fuel model and could lead to the development of custom fuel models. The shrubland vegetation across the Mediterranean basin is characterized by high specific and structural heterogeneity and complexity, determined by the interaction of sub-arid Mediterranean climate and human factors. Unlike other vegetation types, the living vegetation of shrubland is the main component of the bulk of fuel available to fire. In addition, it is more flammable than other vegetation types because of the low moisture content and the presence of volatile oils in most species. Mediterranean shrublands can sustain high intensity fires in relatively moderate environmental conditions and within a few days after rainfall. Therefore, the fuel model and the additional parameters used in FARSITE could be able to reproduce these characteristics. Finally, the capabilities of FARSITE simulator could be affected by other characteristics of fire; in Mediterranean basin, most fires are characterized by very short duration and occur in areas with complex steep terrain. Those conditions result in a great spatial variability of wind speed and direction. So, realistic predictions of fire behaviour depend on the consistency and accuracy of the weather input data needed to run the simulation. The main aim of this study was to evaluate the capabilities of FARSITE simulator in accurately forecasting the fire spread and behaviour in Mediterranean areas. The analysis was carried out on three human caused fire that occurred in North East Sardinia (Italy) during the 2003 and 2004 summer seasons. The burned areas are characterized by the sub-arid Mediterranean climate and were mainly covered by the typical shrubland Mediterranean vegetation, with plants height ranging from 1 to 4 m. Dominant species included Pistacia lentiscus L., Myrtus communis L., Cistus monspeliensis L., Calycotome spinosa, and Arbutus Unedo. Several themes were acquired and managed using Geographic Information System to obtain the spatial inputs required to run FARSITE simulator. The grid resolution of data was 15 m. Fuel and canopy cover map were identified by classification of aerial photographs and field sampling. Several simulations were run using five standard fuel models: model nos 2, 4 and 6 by Anderson, model nos 142 (SH2) and 147 (SH7) by Scott Burgan. All the FARSITE simulations overestimated the actual fire perimeter. The custom fuel model realized in this study provided the better estimation of the fire perimeters and rate of spread, whereas the standard models gave unrealistic simulation of the rate of spread. The custom fuel model reflects the structure and conditions of the mature shrubland typical of most areas of Sardinia; in these conditions the simulator exhibits a good accuracy.
Evaluation of FARSITE simulator in Mediterranean shrubland
ARCA B;DUCE P;PELLIZZARO G;SALIS M;
2006
Abstract
FARSITE is a spatially and temporally explicit fire simulator system based on the physical statistical fire spread model of Rothermel. This simulator allows the user to describe the spread and behaviour of fire under different terrain, fuels and weather conditions. Although FARSITE was originally developed for long range simulation of prescribed fires in US National Parks and wilderness areas, currently the most common applications of the simulator involve the planning and operational phases of fire management. The use of FARSITE on areas different from those where the simulator was originally developed requires a local calibration to obtain reliable results. The local calibration and validation is particularly important to choose the fuel model and could lead to the development of custom fuel models. The shrubland vegetation across the Mediterranean basin is characterized by high specific and structural heterogeneity and complexity, determined by the interaction of sub-arid Mediterranean climate and human factors. Unlike other vegetation types, the living vegetation of shrubland is the main component of the bulk of fuel available to fire. In addition, it is more flammable than other vegetation types because of the low moisture content and the presence of volatile oils in most species. Mediterranean shrublands can sustain high intensity fires in relatively moderate environmental conditions and within a few days after rainfall. Therefore, the fuel model and the additional parameters used in FARSITE could be able to reproduce these characteristics. Finally, the capabilities of FARSITE simulator could be affected by other characteristics of fire; in Mediterranean basin, most fires are characterized by very short duration and occur in areas with complex steep terrain. Those conditions result in a great spatial variability of wind speed and direction. So, realistic predictions of fire behaviour depend on the consistency and accuracy of the weather input data needed to run the simulation. The main aim of this study was to evaluate the capabilities of FARSITE simulator in accurately forecasting the fire spread and behaviour in Mediterranean areas. The analysis was carried out on three human caused fire that occurred in North East Sardinia (Italy) during the 2003 and 2004 summer seasons. The burned areas are characterized by the sub-arid Mediterranean climate and were mainly covered by the typical shrubland Mediterranean vegetation, with plants height ranging from 1 to 4 m. Dominant species included Pistacia lentiscus L., Myrtus communis L., Cistus monspeliensis L., Calycotome spinosa, and Arbutus Unedo. Several themes were acquired and managed using Geographic Information System to obtain the spatial inputs required to run FARSITE simulator. The grid resolution of data was 15 m. Fuel and canopy cover map were identified by classification of aerial photographs and field sampling. Several simulations were run using five standard fuel models: model nos 2, 4 and 6 by Anderson, model nos 142 (SH2) and 147 (SH7) by Scott Burgan. All the FARSITE simulations overestimated the actual fire perimeter. The custom fuel model realized in this study provided the better estimation of the fire perimeters and rate of spread, whereas the standard models gave unrealistic simulation of the rate of spread. The custom fuel model reflects the structure and conditions of the mature shrubland typical of most areas of Sardinia; in these conditions the simulator exhibits a good accuracy.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
