Review of Regional Haze Situation for October 2022 |

Review of Regional Haze Situation for October 2022

1.1 Southwest Monsoon conditions transitioned to the inter-monsoon in late October 2022 as the monsoon rainband moved over the Equator and the prevailing winds gradually weakened and turned light and variable over the equatorial ASEAN region (Figure 1).

1.2 Rainy conditions prevailed over most parts of the ASEAN region in October 2022, except for parts of northeastern Mekong sub-region. In the 3rd week of October, Typhoon Nesat made landfall in the Philippines and contributed to the heavy rainfall over northern parts of the country. It also brought increased rainfall over central Viet Nam as it weakened into a tropical depression before making landfall (Figure 1). The southern ASEAN region experienced continued shower activities during the review period and Alert Level 0 was issued for the region on 12 October 2022, signaling the end of its traditional dry season.

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

1.3 In October 2022, overall hotspot activity in the ASEAN region was subdued under wet weather conditions. While majority of the hotspots in the Mekong sub-region were detected in Viet Nam, the hotspot counts for northern ASEAN region were generally lower or comparable to the counts in previous years (Figure 2). For the southern ASEAN region, hotspot counts were significantly lower compared to the same period in previous years (Figure 3).

Figure 2: Hotspot counts for the northern ASEAN region for the month of October (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 southern ASEAN region for the month of October (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 For the October 2022 review period, few to isolated hotspots were detected in the ASEAN region on most days. In term of persistency, these hotspots were mostly short-lived and did not contribute to any significant smoke haze in October 2022 (Figure 4).

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

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

1.5 The overall fire intensity of hotspots detected over the ASEAN region was low in October 2022. On most days, no smoke plumes were discernable from satellite imagery (Figure 5).