Meteorological Conditions in South East Asia: 4 May 1999

Meteorological Conditions in SouthEast Asia

4 May 1999

After receiving reports of smoke pollution on last Friday (30 April) the Meteorological Service of Singapore reports on 3 May 1999 for the South East Asian region: “Cloudy conditions were observed over central and northern Sumatra and most parts of Kalimantan. Isolated hot spots were detected over central Sumatra”.

Fig.1. Regional Surface Winds and Haze/Hot Spot Map, 3 May 1999
(Source: Meteorological Service of Singapore)

The following NOAA14 satellite image shows hot spots in central Sumatra.

Fig.2. Latest NOAA Satellite image for Sumatra of 3 May 1999
(source: http://www.gov.sg/metsin/hazed.html)

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 2 May 1999 these parameters show various fire weather conditions over South East Asia. The ISI readings are recorded for Kalimantan (Borneo), with the highest Initial Spread Index of 16. The DMC readings in the north-western part of Thailand were also increasing up to the highest rate of 91. Observations in countries of South East Asia reveal that the fire danger situation starts to increase and can reach locally a dangerous level.

Fig.3. and 4. ISI and DMC output of the ASFWIS

The Indonesian Meteorological Agency Badan Meteorologi dan Geofisika forecasts rainy and cloudy conditions for Indonesia with maximum temperatures between 29°C (Palembang), 34°C (Samarinda), 30°C (Ujung Pandang), 31°C (Dili) and 26°C (Bandung) and relative humidity ranging from 49% up to 99%.

The Forest Fire Prevention and Control Project (FFPCP) in Palembang (Sumatra) shows an updated fire overview map of 3 May 1999 of Sumatra.

Fig.5. Fire Overview Map for 3 May 1999 of the FFPCP project in Palembang
(source: http://www.mdp.co.id/ffpcp/overview.htm)

Also no fire update information is currently provided by the Integrated Forest Fire Management (IFFM) project in Samarinda (East Kalimantan).

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.