The Meteorological Service of Singapore reports on 18 May 1999 for the South East Asian region: “Cloudy conditions were observed over northern Sumatra and most parts of Borneo. The region is free of smoke haze”.
Fig.1. Regional Surface Winds and Haze/Hot Spot Map, 18 May 1999
(Source: Meteorological Service of Singapore)
The ASEAN Fire Weather Information System (ASFWIS) is a co-operation between ASEAN and the Canadian Forest Service. It provides maps describing the current fire weather situation in South East Asia. This system is based upon the Canadian Forest Fire Danger Rating System (CFFDRS) (for further infomation to the CFFDRS refer to ASFWIS). Studies have shown that the CFFDRS is applicable outside of Canada. Currently it is also used in a modified form in New Zealand (see References). In New Zealand the Fire Weather Indices Fine Fuel Moisture Code (FFMC) and the Initial Spread Index (ISI) represent the fire danger in the scrublands. The Duff Moisture Code (DMC) is also applicable in South East Asia, because it potentially describes the moisture state of the upper peat layers in peat and peat swamp forests. All three parameters may serve as a suitable indicator of forest fire danger in South East Asia.
According to the ASFWIS for 18 May 1999 these parameters show various fire weather conditions over South East Asia. The FFMC, ISI and DMC are high in Java.
Fig.2., 3.and 4. FFMC, ISI and DMC output of the ASFWIS
The Indonesian Meteorological Agency Badan Meteorologi dan Geofisika forecasts cloudy to rainy conditions for Indonesia. Relative humidity is ranging from 52% up to 98%, and maximum temperatures were measured representative for following areas:
Palembang Samarinda Ujung Pandang Dili Bandung 33°C 32°C 32°C 32°C 30°C
The Forest Fire Prevention and Control Project (FFPCP) in Palembang (Sumatra) provides a new map on 18 May, however no hot spots were detected. For the last map showing hot spots see 5 May fire update.
Summary: Although the current fire weather conditions do under normal conditions not favour extensive land clearing by fire or escaping wildfires in Indonesia, the consequences of the large wildfires of 1997-98 must been taken into consideration. These fires had caused extensive degradation of primary and secondary forests along with the spreading of “alang-alang” (Imperata cylindrica) grasslands. These grasslands facilitate the spread of uncontrolled fires over large areas.