Review of Regional Haze Situation for June 2023
1.1 Southwest Monsoon conditions were fully established in June 2023, with the passage of the monsoon rainband north of the Equator. The prevailing winds over areas north of the equator blew mainly from the southeast or southwest, while the prevailing winds blew mostly from the east or southeast (Figure 1).
1.2 Brief periods of dry weather conditions were observed over parts of southern Sumatra, southern Kalimantan, Java, and the Lesser Sunda Islands. Elsewhere in the ASEAN region, shower activities were observed on most days during the month (Figure 1).
1.3 There was an increase in overall hotspot activity in June 2023 over the southern ASEAN region due to brief periods of dry conditions, with the hotspot counts in the region higher or comparable to previous years (Figure 2). In particular, the highest hotspot activity was detected in Sumatra, and the hotspot counts for both Sumatra and Kalimantan were the highest in 5 years. Over the Mekong sub-region, the overall hotspot count was mostly lower than in previous years (Figure 3).
1.4 Hotspot activities were more persistent in parts of western and central Sumatra, as well as West Kalimantan during the review period of June 2023. Localised smoke plumes were also observed to emanate from a few hotspots in Sumatra and Kalimantan on some days (Figures 6 and 7). However, the overall fire intensity has generally remained low.