Review of Regional Haze Situation for September 2020
1.1 Southwest Monsoon conditions persisted over the ASEAN region in September 2020 and the prevailing winds blew mainly from the southeast or southwest. In the northern ASEAN region, rainy weather persisted throughout most of the month, particularly during the third week when Tropical Storm Noul made landfall over the Mekong sub-region and brought widespread showers. Average daily rainfall (Figure 1) was highest in coastal areas of Vietnam, Cambodia and Myanmar. In the southern ASEAN region, shower activities were frequently observed over many areas despite this period of the year being its traditional dry season. Average daily rainfall was highest in northwestern Borneo, northern Sumatra and West Papua while generally dry conditions were observed mainly over the Java Sea region.
Figure 1: Average Daily Rainfall and Mean Wind for September 2020. (Source: JAXA GsMaP and GFS respectively)
1. 1.2 The hotspot counts in the ASEAN region for September 2020 remained relatively low when compared to the same review period in previous years due to wet weather (Figure 2 and Figure 3).
Figure 2: Hotspot counts for the southern ASEAN region for September 2016 – 2020. [Note: The hotspot counts from 2019 are based on the NOAA-20 satellite, while those from 2016-2018 are based on the Suomi-NPP satellite.]
Figure 3: Hotspot counts for the northern ASEAN region for September 2016 – 2020. [Note: The hotspot counts from 2019 are based on the NOAA-20 satellite, while those from 2016-2018 are based on the Suomi-NPP satellite.]
1.3 Isolated hotspots were detected in many parts of the ASEAN region in September 2020. In particular, persistent clusters of hotspots were detected in Viet Nam, the Lesser Sunda Islands, and some parts of Kalimantan (Figure 4). Localized smoke haze was also observed to emanate from some of the intense hotspots in Kalimantan during the second half of the month.
Figure 4: Distribution of hotspots detected based on NOAA-20 satellite surveillance for September 2020.
Figure 5: Maximum fire intensity based on NOAA-20 satellite surveillance for September 2020.