Review of Regional Haze Situation for January 2021
1.1 Northeast Monsoon conditions prevailed over the ASEAN region in January 2021. In the northern ASEAN region, the prevailing winds blew mainly from the northeast or east, strengthening at times under the influence of high-pressure systems moving eastwards over continental Asia. Dry conditions persisted over the Mekong sub-region while wet weather conditions were observed mostly over the eastern parts of the Philippines. In the southern ASEAN region, the prevailing winds blew mainly from the northwest or northeast over areas near the Equator, and mainly from the west or northwest over areas south of the Equator. There were isolated to scattered shower activities over the region, with rainfall observed to be higher over parts of Malaysia, Singapore, North Kalimantan, central Sumatra, and Java Island.
Figure 1: Average Daily Rainfall and Mean Wind for January 2021. (Source: JAXA GsMaP and GFS respectively)
1.2 The hotspot counts in the ASEAN region for January 2021 were comparatively lower than those from the same review period in previous years, with the exception of Myanmar (Figure 2 and Figure 3).
Figure 2: Hotspot counts for the northern ASEAN region for the month of January (2017 – 2021). [Note: The hotspot counts from 2019 onwards are based on the NOAA-20 satellite, while those from 2017 – 2018 are based on the Suomi-NPP satellite.]
Figure 3: Hotspot counts for the southern ASEAN region for the month of January (2017 – 2021). [Note: The hotspot counts from 2019 onwards are based on the NOAA-20 satellite, while those from 2017 – 2018 are based on the Suomi-NPP satellite.]
1.3 In the northern ASEAN region, hotspot activities were detected in many parts of the Mekong sub-region. In particular, persistent clusters of hotspots were detected in the northeastern parts of Myanmar, and the northern and eastern parts of Cambodia (Figure 4 and Figure 5). During the first fortnight of the month, moderate smoke haze was first observed to emanate from the hotspot clusters in the northern and eastern parts of Cambodia (Figure 6).
1.4 In view of the prolonged dry conditions, increased hotspot activities and persistent hotspot clusters in the Mekong sub-region, the Alert Level was raised to Level 2 for the sub-region on 14 January 2021. The hotspot and haze situation in the Mekong sub-region further deteriorated during the second fortnight of the month when moderate smoke haze was observed over larger areas of Cambodia, as well as over parts of Thailand and Myanmar (Figure 6). In particular, dense smoke haze was detected over the northern and eastern parts of Cambodia towards the end of the month. In the southern ASEAN region, hotspot activities were subdued due to the wet weather conditions.
Figure 4: Distribution of hotspots detected based on NOAA-20 satellite surveillance for January 2021.
Figure 5: Maximum fire intensity based on NOAA-20 satellite surveillance for January 2021.
Figure 6: Number of days with moderate to dense smoke haze observed over an area based on satellite imagery, ground observations and air quality reports in January 2021.