Fire Regime Analysis in Lebanon (2001–2020): Combining Remote Sensing Data in a Scarcely Documented Area

Abstract

Fire is a recurrent disturbance in Mediterranean ecosystems. Data assemblage from forest fire services can provide useful information for understanding climate controls on daily fire hazard or long term trends. Located at the driest range of the Mediterranean bioclimate, and with contrasting socio-political systems compared to the European area, the southern Mediterranean ecosystems are subjected to more extreme climate and social events. This could potentially lead to unique fire regimes and trends worth being characterized for prevention plans and ecosystem management. However, the region is far less documented, due to missing or inhomogeneous fire records, leaving local authorities with no management strategies when large fires happen. We filled this knowledge gap for Lebanon by combining high spatial resolution Landsat data with high temporal resolution VIIRS (S-NPP and NOAA-20) and MODIS (MCD14ML) hotspots to characterize the seasonal and interannual fire regime over the 2001–2020 period. Numerous small fires were hardly detected by global remote sensing. We estimated that 2044 ha burn annually, representing 0.58% of the wildland cover, with no significant trend over the period, but with non climate-related fires detected during the year experiencing socio-political troubles. The spatial and temporal resolution of this dataset identified a particular prolonged fire season up to November, and an unusual bimodal fire season peaking in July and November. We related these features to the prolonged autumnal soil drought and high August air humidity in the region. This updated fire regime in Lebanon illustrates the benefits of this combined approach for data-scarce regions and provides new insights on the variability of fire weather types in the Mediterranean basin.

Constructing a Comprehensive National Wildfire Database from Incomplete Sources: Israel as a Case Study

“…In turn, the wildfire size distribution in the database should reflect as closely as possible the actual wildfire distribution: most of the wildfires are small, few are large, and large wildfires account for the most damage and area burned [61,68]. We found that 10 ha was the minimal burned area that we could detect using multiple independent approaches (both field-based and remotely sensed), and which at the same time corresponded to the actual wildfire size distribution in Israel, which is similar to the size (6.3 ha) found in Lebanon (Israel's neighboring country to the north, which has a similar climate [45]). We stress that the choice of minimal burned area threshold is not straightforward and reflects a tradeoff between detectability and outcome.…”

“…Unfortunately, global fire datasets are not relevant for regions where most fires are small and have a short duration, as they go undetected by NASA's active fire products [33,45]. Taking Israel as an example, the global fire atlas [14] for the years 2015 and 2016 had only 37 and 38 wildfires, with a median area of 21 and 42 ha and a total burned area of 1759 and 2981 ha, respectively.…”

“…However, more than 96% of the burnt area resulted from fires larger than 10 ha, highlighting the disproportional effect of fires larger than 10 ha on fire outcomes. In a recent study of wildfires in Lebanon, the minimum fire size properly captured by remote sensing approaches was 6.3 ha [45]. Following a similar approach, we identified for wildfires in Israel a threshold of 10 ha, which created a right-skewed distribution for all years that corresponds with the actual size distribution of wildfires, i.e., most wildfires are small and few are large, with a power law probability distribution [61,62].…”

“…During this period, the synoptic systems that cause major forest fires are the North African ('Sharav') cyclone and the Red Sea trough system, as they both carry hot and dry air [50]. There is an especially high probability for large fires in the fall, when fuel moisture is especially low after a few months without precipitation [45,79]. The ability of the unified database to reflect these patterns confirms it general validity, opening the door to future analyses that may deliver novel insights about the fire regime in general, and, as importantly, providing information for wildfire management and policy both at local and national scales.…”

40-Year Fire History Reconstruction from Landsat Data in a Mediterranean Area of North Africa Following International Standards

“…These fires may seriously degrade forest habitats in this country, a large part of which may not be restored [9]. However, accurate and spatially explicit BA data about this region, as in several middle-eastern and north-African countries, are scarce or even lacking [10].…”