Review of Regional Haze Situation for July 2023
1.1 Southwest Monsoon conditions persisted in July 2023, with the monsoon rainband located predominantly over the northern ASEAN region. The prevailing winds over areas north of the equator blew mainly from the southeast or southwest, while the prevailing winds over areas south of the equator blew mostly from the east or southeast (Figure 1). Typhoon Talim (Figure 9) and Super Typhoon Doksuri (Figure 10) brought about periods of strong winds over the northern half of the equator.
1.2 Over the southern ASEAN region, brief periods of dry weather conditions were observed for most of July 2023. Towards the end of the month, dry conditions persisted over Kalimantan with clusters of scattered hotspots and slight to moderate smoke haze observed over the western and southeastern parts of Kalimantan. On some days, smoke haze emanating from clusters of hotspots in West Kalimantan was observed to drift northwards into western Sarawak. On 28 July 2023, Alert Level 2 was activated for Kalimantan as hotspot counts were persistently high and there was an increasing risk of transboundary haze. Over the northern ASEAN region, wet weather was observed on most days during the month, subduing the overall haze situation in the region. High rainfall amounts were recorded over the northern parts of the Philippines due to Typhoon Talim which made landfall over the Philippines on July 13, 2023 and Super Typhoon Doksuri which passed the northern tip of the Philippines between July 25 and July 27, 2023.
1.3 Over the southern ASEAN region, there was a rise in overall hotspot activity due to periods of drier conditions, with the hotspot counts in the region higher or comparable to previous years (Figure 2). Notably, Kalimantan experienced the most significant rise in hotspot activity, with the highest count recorded in five years. Over the Mekong sub-region, the overall hotspot count in 2023 was mostly comparable to or lower than in previous years (Figure 3).
1.4 Towards the end of July 2023, hotspot activities were persistent in West and South Kalimantan, as well as parts of the Lesser Sunda Islands (Figure 4). The overall fire intensity for the ASEAN region was low, except for over parts of western Kalimantan where moderate fire intensity was detected (Figure 5). Slight to moderate smoke haze was observed over the western and southeastern parts of Kalimantan (Figures 6, 7 and 8).
