Review of Regional Haze Situation for September 2022 |

Review of Regional Haze Situation for September 2022

1.1 Southwest Monsoon conditions continued to be observed over the ASEAN region in September 2022, with the prevailing low-level winds blowing from the southeast for areas south of the Equator and mainly from the south to southwest for areas north of the Equator (Figure 1).

1.2 The weather over the ASEAN region in September 2022 was mostly rainy, except for parts of Java, Sulawesi, and the Lesser Sunda Islands where there were periods of drier conditions. During the last two weeks of the month, Typhoon Noru brought increased rainfall and strong winds to the northern part of the Philippines and the eastern and central parts of the Mekong sub-region, as it made landfall over Viet Nam on 28 September 2022 (Figure 1).

Figure 1: Average Daily Rainfall and Mean Winds for September 2022. (Source: JAXA GsMaP and GFS, respectively)

1.3 Hotspot activity in the ASEAN region was mostly subdued in September 2022 due to widespread shower activities. For the Mekong sub-region, hotspot counts were generally lower or comparable to previous years, with a majority of the hotspots detected in Viet Nam (Figure 3). Over the southern ASEAN region, despite this period of the year being its traditional dry season, hotspot counts were significantly lower compared to the same period in previous years (Figure 2).

Figure 2: Hotspot counts for the southern ASEAN region for the month of September (2018 – 2022). [Note: The hotspot counts from 2019 onwards are based on the NOAA-20 satellite, while those from 2018 are based on the Suomi-NPP satellite.]

Figure 3: Hotspot counts for the northern ASEAN region for the month of September (2018 – 2022). [Note: The hotspot counts from 2019 onwards are based on the NOAA-20 satellite, while those from 2018 are based on the Suomi-NPP satellite.]

1.4 During the review period, few to isolated hotspots were detected mainly in parts of Viet Nam, Kalimantan, Sulawesi, and the Lesser Sunda Islands on several days. In term of persistency, these hotspots were mostly short-lived and did not contribute to any significant smoke haze in September 2022 (Figure 4).

Figure 4: Distribution of hotspots detected in September 2022 based on NOAA-20 satellite surveillance.

Figure 5: Maximum fire intensity in September 2022 based on NOAA-20 satellite surveillance.

1.5 The overall fire intensity of hotspots detected over the ASEAN region was low in September 2022. No significant smoke haze was observed from satellite imageries and ground reports (Figure 5).