Meteorological Conditions in South East Asia: 1 December 1998

Meteorological Conditions in SouthEast Asia

1 December 1998


The ASEAN Fire Weather Information System (ASFWIS) 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 http://www.nofc.forestry.ca/fire/asean), and is currently tested on an experimental basis. 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 (http://www.nofc.forestry.ca/fire/asean/) for 24 November 1998 these parameters are slightly increasing almost all over South East Asia.  The highest FFMC readings are recorded for northern Vietnam, with the FFMC ranging between 90-92. Due to changed weather conditions, the ISI readings  in northern Thailand and northern Vietnam decreased over the last days.

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Fig.1. FFMC output of the ASFWIS

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 Fig.2. DMC output of the ASFWIS

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Fig.3. ISI output of the ASFWIS

These findings are consistent with the current weather reports from Badan Meteorologi dan Geofisika (http://bmg.cbn.net.id/) which records rainy and cloudy conditions for Indonesia with temperatures between 20°C (Bandung) and 34°C (Pekanbaru) with relative humidity ranging from 60% up to 97%.   The general forecast for whole Indonesia is rainy and cloudy.

The Meteorological Service of Singapore (http://www.gov.sg/metsin/hazed.html) reports for the South East Asian region “slight smoke haze observed over Singapore, Peninsular Malaysia and central Sumatera. It is expected to clear in the next 1 to 2 days”. The Meteorological Service states for the near future that: “rainfall in the region is expected to be near or above normal for the next few months. However it should be noted that many parts of Indonesia (Kalimantan and parts of Sumatera) would be in their traditional dry season in the next few months. As such, though extensive and prolonged smoke haze is unlikely for this period, occasional short periods (e.g. a few days) of slight to moderate haze in a more localised manner remain probable”.

The FFPCP project in Palembang (http://www.mdp.co.id/ffpcp/overview.htm) records  no hotspots on 30 November 1998. On  29 November 40 hotspots with   an detection threshold of 310 K were detected and on 28 November 26 hotspots with an detection threshold of 320 K. The burning activities detected by the NOAA AVHRR sensor are land clearing fires. Attention must be given to prevent the escape of these land-use fires into surrounding vegetation.

Summary: Although the current fire weather conditions do under normal conditions not favour extensive land clearing by fire or escaping wildfires, 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. It can be predicted that in November-December with only moderate fire danger new vegetation fires will occur.

See also the IFFN Country Notes.

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