Review of Regional Haze Situation for December 2022
1.1 In December 2022, the Northeast Monsoon was well established over the ASEAN region as the predominant low-level winds blew from the northeast over areas north of the Equator and blew from the west or northwest over areas south of the Equator. The northeasterly winds strengthened at times, bringing a monsoon surge over the South China Sea and parts of the Mekong sub-region (Figure 1).
1.2 During the month, dry conditions were experienced over most parts of the Mekong sub-region except for the southeastern parts of the sub-region where some rainfall was observed. Alert Level 1 for the onset of the dry season in the northern ASEAN region was issued on the 15 December 2022. Wet weather was experienced elsewhere in the ASEAN region with the highest rainfall observed over the eastern parts of the Peninsular Malaysia and the southern parts of Thailand and the Philippines (Figure 1), under the influence of the monsoon surge. Floods and landslides were also reported in these areas on several days during the month which resulted in several fatalities and displacement of people from their homes.
1.3 1.3 There was an increase in the overall hotspot activities in the Mekong sub-region following the onset of the dry conditions over the sub-region in December 2022 with the highest hotspot activity detected in Cambodia (Figure 2). In the southern ASEAN region, hotspot activities were mostly subdued due to the prevailing wet weather (Figure 3). While the hotspot activities in ASEAN region were mostly comparable to the same month in previous years, there was a noticeable increase in the hotspot activities in Cambodia compared to the last two years.
1.4 In the northern ASEAN region, isolated to scattered hotspots were detected mostly in the Mekong sub-region. The hotspots were more persistent in the northern and eastern parts of Cambodia, the southern parts of Myanmar, the northern parts of Viet Nam and the northern and central parts of Thailand (Figure 4). While the overall fire intensity of hotspots was low, localised smoke plumes were observed to emanate from hotspots in the eastern parts of Cambodia and northern parts of Viet Nam where the fire intensity was slightly higher (Figure 5). In the southern ASEAN region, hotspot activities were subdued due to the wet weather with few hotspots detected in Sumatra, Kalimantan and Sulawesi.