Evaluating Skill of the Keetch–Byram Drought Index, Vapour Pressure Deficit and Water Potential for Determining Bushfire Potential in Jamaica

• Published in: Atmosphere 2022-08, Vol.13 (8), p.1267
• Main Authors: Charlton, Candice, Stephenson, Tannecia, Taylor, Michael A., Campbell, Jayaka
• Format: Article
• Language: English
• Subjects: Archives & records; Atmospheric models; bushfire potential; Caribbean; Climate change; Climate models; Climatic indexes; Climatology; Correlation; Drought; Drought index; Droughts; Environmental aspects; Evaluation; False alarms; Fire prevention; Fires; Forest & brush fires; Forest fires; Humidity; Jamaica; KBDI; Lag time; MODIS; Monitoring; Precipitation; Rain; Regression analysis; Regression models; Statistical analysis; Temperature; Vapor pressure; Vapour pressure; vapour pressure deficit; Variability; Water potential; Weather; Wildfires
• ISSN: 2073-4433; 2073-4433
• DOI: 10.3390/atmos13081267

Bushfire management which incorporates fire potential indices is still in its infancy in Jamaica and the Caribbean. In this study three bushfire potential indices—Keetch–Byram Drought Index (KBDI), Vapour Pressure Deficit (VPD) and Water Potential (Ψw)—are calculated for south-central Jamaica where bushfire frequencies are highest. The skills of the indices are evaluated using their representation of the normalised bushfire climatology, monthly and seasonal (December–March/DJFM; April–June/AMJ; July–August/JA and September–November/SON) fire variability for the periods 2013–2017, 2010–2019 and 2001–2019. Fire data are obtained from the MODIS C6 Archive and Jamaica Fire Brigade (JFB). The relationship between the fire indices and large-scale oceanic and atmospheric features are also examined. The results suggest that Ψw exhibits strong correlations with the MODIS and JFB climatologies and represents well the maxima in March and July and the local minima in May–June and October. Ψw and VPDI also show good hit rates for moderate and high-risk categories in south-central Jamaica (though with relatively high false alarm rates). Regression models premised on Ψw and VPD respectively show good skill in representing AMJ (R2 = 57–58%), SON (R2 = 57–58%) and JA (R2 = 57–60%) fire variability. Variability during DJFM is poorly captured by any fire index. Although the KBDI represents the normalised climatology reasonably well its peaks occur one month later, that is, in April and August. KBDI exhibits strong and statistically significant correlations with JFB and MODIS climatologies, but seasonal models premised on KBDI do not perform as well as for the other two indices except in JA. All indices had a statistically significant relationship on both monthly and 1 month lag time scales for NINO3 and TNA-NINO3 large-scale climate indices. The indices, and in particular Ψw, show good prospects for producing seasonal bushfire outlooks for south-central Jamaica and Jamaica in general. These results also suggest the usefulness of monitoring large-scale oceanic patterns as part of the monitoring framework for bushfires in the island.