| Long-term analyses of Indonesia's serious smoke haze problem have been limited due to the lack of fire records or air quality measurements. In response, a monthly indicator of smoke haze has been developed for Indonesia using visibility observations. Visibility signals were developed for the fire prone regions of southern Sumatra and southern Kalimantan, and compared to several moisture indices to determine the relationship between drought and smoke haze from 1979 to 2003. Analysis of haze signals showed that (i) 1997 fire event was of an unprecedented magnitude, (ii) the 2002 haze event occurred under only moderate drought, and (iii) Indonesia's fire environment is becoming more sensitive. Nonlinear regression techniques showed that simple rainfall-based indices are preferable to complicated soil moisture models in predicting severe haze events, which have occurred historically when the 3-month total rainfall drops below 337.26mm (247.83, 404.93) in Sumatra and 414.25 mm (381.01, 467.89) in Kalimantan. |
