Barbero R., Moron V., Mangeas Morgan, Despinoy Marc, Hély C. (2011). Relationships between MODIS and ATSR fires and atmospheric variability in New Caledonia (SW Pacific). Journal of Geophysical Research. Atmospheres, 116, p. D21110. ISSN 0148-0227.
Titre du document
Relationships between MODIS and ATSR fires and atmospheric variability in New Caledonia (SW Pacific)
Barbero R., Moron V., Mangeas Morgan, Despinoy Marc, Hély C.
Source
Journal of Geophysical Research. Atmospheres, 2011,
116, p. D21110 ISSN 0148-0227
We examined the relationships between fires detected by the Along Track Scanning Radiometer, algorithm 2 (ATSR-2) and the Moderate Resolution Imaging Spectrometer (MODIS) sensors and local-scale atmospheric conditions in New Caledonia (SW Pacific similar to 165.5 degrees E, 21.5 degrees S) during the 1996-2008 (ATSR) and 2000-2008 (MODIS) time periods. A total of 3707 (MODIS) hotspots, representing 949 distinct fires, and 83 (ATSR) hotspots were observed during the study period. The annual mean frequency of hotspots peaks around the transition between the dry-cool season and the wet-warm season, that is, in September-December, when dry soils and fuels could be combined with increasing temperatures. The antecedent local-scale maximum temperature and rainfall anomalies recorded at the closest meteorological station were analyzed. While the signal in maximum temperature is weak and not robust among the fire records, the local-scale anomalies of rainfall are always clearly negative for at least 3 months before the fires (i.e., between June and December). The Effective Drought Index (EDI), based on rainfall only, and the Fire Weather Index (FWI), which combines rainfall, temperature, relative humidity, and wind speed, show similar behaviors before fires. This suggests that a simple rainfall index, as well as a more comprehensive one, is able to diagnose fire risks. At interannual time scale, cross-correlation analysis reveals that the seasonal June-August Nino 3.4 sea surface temperature index is strongly correlated (r = 0.78 for a second-order polynomial fit) with the monthly frequency of all MODIS hotspots in September-December, suggesting a strong potential predictability of fire variations in New Caledonia with a lead time of 1-4 months.
